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Women's preferences for contralateral prophylactic mastectomy following unilateral breast cancer: What risk-reduction makes it worthwhile?
The Breast 31 (2017) 233e240
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Original article
Women's preferences for contralateral prophylactic mastectomy following unilateral breast cancer: What risk-reduction makes it worthwhile? Stephanie Tesson a, b, *, Imogen Richards a, David Porter c, Kelly-Anne Phillips d, e, f, g, Nicole Rankin h, Daniel Costa i, Toni Musiello j, Michelle Marven k, Phyllis Butow b, l a
School of Psychology, The University of Sydney, NSW, Australia Psycho-Oncology Co-operative Research Group (PoCoG), The University of Sydney, NSW, Australia Department of Oncology, Auckland Hospital, Auckland, New Zealand d Division of Cancer Medicine, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia e Department of Oncology, Peter MacCallum Cancer Centre, The University of Melbourne, Melbourne, VIC, Australia f Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, Australia g Department of Medicine, St Vincent's Hospital, The University of Melbourne, Melbourne, VIC, Australia h Sydney Catalyst Cancer Translational Cancer Centre, The University of Sydney, NSW, Australia i Pain Management Research Institute, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia j University of Western Australia, Perth, WA, Australia k Breast Cancer Network Australia (BCNA), Melbourne, VIC, Australia l Centre for Medical Psychology and Evidence-based Decision-making (CeMPED), The University of Sydney, NSW, Australia b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 20 July 2016 Received in revised form 23 October 2016 Accepted 30 November 2016
Objectives: Contralateral prophylactic mastectomy (CPM) reduces the risk of contralateral breast cancer (BC) following unilateral BC, but may not increase survival in BRCA1/2 mutation negative women. Despite this, and the risk for adverse physical and psychological impact, uptake is increasing in BRCA1/2 mutation negative women. We aimed to quantify the degree of reduction in lifetime contralateral BC risk women required to justify CPM, and to explore demographic, disease and psychosocial predictors of preferences using Protection Motivation Theory (PMT) as a theoretical framework. Reasoning behind preferences was also examined. Materials and methods: 388 women previously diagnosed with unilateral BC, of negative or unknown BRCA1/2 status, were recruited from an advocacy group research database. Two hypothetical risk tradeoff scenarios were used to quantify the reduction in lifetime contralateral BC risk that women judged necessary to justify CPM, using a 5% and 20% baseline. Demographic, disease and PMT measures were assessed using a questionnaire. Results: Most women required their risk to be more than halved from a 5% or 20% baseline to justify CPM. Polarised preferences were also common, with some women consistently accepting or refusing CPM independent of risk/benefit trade-offs. Preferences were associated with coping self-efficacy and having a prior CPM. Explanations for judging CPM worthwhile included reducing or eliminating contralateral BC risk, attaining breast symmetry and reducing worry. Conclusion: Risk-reduction preferences were highly variable. Decisive factors in women's preferences for CPM related to clinical, psychological and cosmetic outcomes, but not to demographic or disease characteristics. © 2016 Elsevier Ltd. All rights reserved.
Keywords: Breast cancer Contralateral breast cancer Contralateral prophylactic mastectomy Decision-making Patient preferences
1. Introduction * Corresponding author. School of Psychology, Chris O'Brien Lifehouse, Level 6 North (C39Z), The University of Sydney, Camperdown, NSW, 2006, Australia. E-mail address: [email protected] (S. Tesson). http://dx.doi.org/10.1016/j.breast.2016.11.025 0960-9776/© 2016 Elsevier Ltd. All rights reserved.
Women diagnosed with unilateral breast cancer (BC) are increasingly undergoing contralateral prophylactic mastectomy (CPM) worldwide [1,2]. Amongst 1.1 million American BC patients,
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CPM rates rose from 2.0% to 12.3% from 1998 to 2011 [3]. CPM reduces risk of contralateral breast cancer (CBC) [4] and may increase life expectancy for BRCA1/2 carriers, who have a 3e4% annual risk of CBC [5,6]. For women without BRCA1/2 mutations, however, CBC risk is often much lower, estimated in contemporary reports at 0.19e0.5% per annum on average [7,8], and CPM is unlikely to improve life expectancy, thus uptake is controversial. Close surveillance often facilitates early detection and curative treatment of any occurring CBC's [9]. Furthermore, CPM cannot prevent metastatic disease from the first BC, which often poses a substantially higher risk than CBC and principally determines overall survival [10]. CPM carries a risk of postoperative complications [11], and can negatively impact on body image, perceived femininity and sexual intimacy [12], leading to post-surgical regret [13]. Despite this, women without BRCA1/2 mutations are increasingly undergoing CPM. A study of 2695 BC patients reported 24.2% CPM uptake, yet only 13% had documented BRCA1/2 mutations [14], leading to concerns about potential overtreatment without objective medical necessity [15]. Research has explored clinical, demographic and psychological predictors of CPM uptake, including overestimated perceptions of CBC risk and CPM's survival benefit [16], avoidance of future breast surveillance [2,16], and desire for breast symmetry after unilateral mastectomy [17]. Social-cognitive and emotional factors identified as influential in CPM decision-making include women's expectations of positive or negative CPM outcomes, avoiding uncertainty and regret, reducing recurrence-related anxiety, and social norms [17e19]. Demographically, women who are younger, with higher education, Caucasian ethnicity, a family history of BC, and intentions for breast reconstruction, are more likely to undergo CPM [20,21]. However, research has typically focused on high-risk mutation carriers, or failed to identify mutation status [22]. Thus, findings may not generalise to lower-risk women. Reviews highlight the need for more evidence about factors prompting CPM uptake in BRCA1/2 negative women [22,23]. Risk-trade off scenarios provide insight into how patients weigh treatment benefits against treatment harms or inconveniences [24]. Understanding the minimum benefit needed to justify CPM is important to guide ethical, preference-sensitive discussion of CPM. Studies of early BC patients find that many women accept adjuvant endocrine and chemotherapy for 0.1e2% absolute gains in survival [25,26]. Yet no published study has quantified the amount of riskreduction women require to justify CPM. Protection Motivation Theory [27] is a theoretical framework that aims to explain patient preferences, emphasising: perceived: severity and vulnerability to a disease threat, efficacy of a healthprotective behaviour in reducing threat, self-efficacy to undertake the behaviour, and response costs or negative behavioural consequences [27]. PMT has shown utility in explaining intentions for numerous cancer preventative behaviours including adjuvant therapy uptake [28], breast self-examination [29], gene mutation screening [30], and CPM [18]. Accordingly, we aimed to determine the minimum degree of CBC risk-reduction that women of negative or unknown BRCA1/2 status required to justify CPM. We also aimed to identify demographic, clinical and psychosocial predictors of women's riskreduction preferences using PMT as a theoretical framework. Participants reporting greater severity, vulnerability, self-efficacy, response efficacy, and lower response cost scores, were expected to require less risk-reduction.
2. Method 2.1. Participants Participants were members of Breast Cancer Network Australia's (BCNA) Review and Survey Group database. BCNA is Australia's largest BC advocacy organisation, comprising over 110,000 members. Participants were aged 18e70, and had completed primary treatment (i.e., surgery, chemotherapy, radiotherapy) for a unilateral BC diagnosis 0e10 years prior. Participants could be continuing endocrine therapy. Exclusion criteria included: (i) a diagnosis of metastatic or second primary BC, (ii) known BRCA1/2 positive status, and/or (iii) inadequate English language skills to complete the questionnaire. 2.2. Procedure BCNA database members were sent an introductory email including eligibility criteria, a participant information sheet and survey web-link. Individuals could anonymously complete the questionnaire after providing online consent or seek clarification from the research team. Reminder emails were sent twice, two weeks apart. Participants completed demographic and disease items, then read a fact sheet and hypothetical scenario. The fact sheet was based on National Cancer Institute online materials [31], designed in liaison with two medical oncologists, and outlined risks and benefits of different CBC risk-management options (CPM, chemoprevention, hormone therapy, surveillance), to ensure all participants responded with similar knowledge. The hypothetical scenario described a pre-menopausal 48-year-old woman (Mary) diagnosed with early-stage unilateral BC, deliberating her CBC-risk management options after a unilateral mastectomy and chemotherapy. This hypothetical scenario aimed to minimise distress by distancing women from personal treatment decisions. Participants were asked to complete PMT and risk trade-off measures considering Mary's scenario, alongside their own values. 2.3. Measures 2.3.1. Demographic and disease variables Demographic variables assessed included: age, ethnicity, language/s spoken, Aboriginal or Torres Strait Islander background, current children, plans for future children, dependents, marital status, education and residential location. Disease variables included age at unilateral BC diagnosis, primary unilateral BC treatment, lymph node surgery, hormone treatment, private health insurance, CPM status (having had a prior CPM vs. not), and intentions for breast reconstruction if CPM were undertaken. 2.3.2. Risk-reduction preferences Risk-reduction preferences were assessed using two risk tradeoff scenarios adapted from Simes and Coates [32], aiming to determine the minimum degree of risk-reduction required to justify CPM. Participants were asked to sequentially indicate whether they would, or would not, have CPM for increasing degrees of reduction in lifetime CBC risk from a 5% or 20% baseline (the two separate scenarios). These baselines were chosen to cover the range of risks likely in the modern treatment context. For example, in the 5% scenario, participants sequentially indicated whether they would, or would not, have CPM if it reduced their risk from a baseline of 5%e0% (i.e., completely eliminated risk) then to 0.5%, 1%, 1.5% (and so on by 0.5% increments to 5%, at which point CPM offers no risk-reduction). Free-text questions then asked
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participants to list the six primary factors (three incentives, three barriers) influencing their decision-making. 2.3.3. Psychosocial constructs 2.3.3.1. PMT constructs. PMT constructs were assessed using multiitem subscales adapted from other PMT studies or informed by the CPM literature [16,19,33]. Responses were ranked on 5-point Likert scales; subscale scores were generated by summing component subscale items. These measures are discussed in-depth elsewhere [18], and were operationalised as follows: Severity: Two item assessed whether developing CBC would be serious and life threatening. Vulnerability: Two items assessed perceived susceptibility to CBC, based on absolute and comparative risk. Response efficacy: Seven items assessed beliefs about CPM's potential cosmetic, medical and emotional advantages. Self-efficacy: Seven items investigated perceived capability to undergo CPM given certain obstacles. Response costs: Seven items assessed perceptions of CPM's potential disadvantages. 2.3.3.2. Other psychosocial variables. Screening capability (4 items) assessed a woman's ability to continue surveillance, cope with risk, further treatment and breast asymmetry. Fear of CBC was assessed using the 9-item Fear of Cancer Recurrence Inventory Severity subscale [34], examining the frequency and duration of CBC-related thoughts and images, scored on a 5-point scale (0 ¼ Not at all/Never, 4 ¼ A great deal/Several times). 2.3.4. Statistical analysis Descriptive statistics are reported for demographic, disease, psychosocial variables, and risk-reduction preferences (RRP). Two RRPs were computed for each participant; one for the 5% scenario, and one for the 20% scenario. This was calculated by subtracting the risk percentage where a participant switched from indicating a preference for not having to having CPM, from the corresponding 5% or 20% baseline risk. Lower RRPs indicated that participants required less risk-reduction to choose CPM. For example, a score of 0 was assigned to a participant consistently choosing CPM, indicating they required 0% risk-reduction from a 5% or 20% baseline. Scores of 5.0 or 20.0 were assigned to participants who only chose CPM if it completely eliminated risk, requiring 5% or 20% risk-reduction from the corresponding baseline risk. Scores of 5.5 or 22.0 (i.e., 10% of the maximum possible score) were assigned for participants who declined CPM irrespective of benefit, requiring more than the highest risk-reduction possible. The primary outcome variable was calculated by summing the two RRPs for the 5% and 20% scenario together proportionally (i.e., riskreductions of 2.5% from a 5% baseline, and 10% from a 20% baseline were considered equivalent). Inappropriate or inconsistent responses were excluded from analyses. Statistical analyses were conducted using IBM SPSS version 20.0. Associations between demographic, clinical and psychosocial variables and total RRP scores were assessed using Pearson's correlations, with variables correlated at the >0.1 level (p < 0.05) used as predictors in multiple linear regression (MLR) analyses. Categorical independent variables with more than two categories were dichotomised. Assumptions of MLR (i.e., normality, linearity, homogeneity of variance) were satisfied; multicollinearity was not problematic. Assuming 21 predictors in the multivariate models, with a Type 1 error rate of a ¼ 0.05, power ¼ 0.90, and Cohen's [35] standardised regression effect size of f2 ¼ 0.15 (medium effect size), the required sample size was calculated as N ¼ 195 using G-power [36].
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Categorisation of free-text qualitative responses was undertaken by two independent coders based on thematic similarity, and refined iteratively until unanimous agreement was reached [37]. Responses covering multiple categories were coded twice to retain fidelity to original answers. 3. Results Table 1 shows participant demographic and disease characteristics. Participants included 388 women with a mean age of 53.2 years (SD ¼ 8.2). Most participants were married/de-facto (79%), had children (79%) and attended university (49%). Mean age at diagnosis was 50.1 years (SD ¼ 8.3). Most participants underwent lumpectomy (36%) or unilateral mastectomy without reconstruction (30%) as primary treatment, and received endocrine therapy (76%). Table 2 shows participant scores on PMT and treatmentrelated measures. 3.1. Risk-reduction preferences Fig. 1 illustrates the proportion of participants choosing CPM for various magnitudes of CBC risk-reduction. For the 5% scenario, over half of women judged that a 2.5% risk-reduction was sufficient to make CPM worthwhile. In the 20% scenario, most women required that their risk be reduced to 14% to justify CPM. Approximately 15% of women in both scenarios would never undergo CPM, even if it completely eliminated CBC risk. Furthermore, 27% of women would undergo CPM for no risk-reduction, qualitatively citing non-clinical benefits, discussed below. 3.2. Bivariate correlations and multivariate analysis Bivariate correlations indicated significant associations between RRP and prior CPM status, perceived screening capability, fear of CBC, severity, response efficacy, self-efficacy and response costs (Table 3). In MLR, only prior CPM and self-efficacy remained significant predictors. That is, women with a prior CPM required 0.56% less risk-reduction to justify CPM, on average, than those without a prior CPM. For each one-point increase in coping self-efficacy (M ¼ 26.8, range: 7e35), women required 0.03% less riskreduction, on average, to justify CPM. 3.3. Qualitative responses Content analysis revealed 32 factors (15 incentives, 17 barriers) influencing women's decision-making. Table 4 summarises the five most influential incentives and barriers to undergoing CPM. CBC risk-reduction or elimination was the most frequently cited incentive, alongside breast symmetry and reducing worry or fear. Avoiding surgery and post-operative risks/consequences was the most commonly reported barrier to CPM, alongside financial cost and time off work. Ambivalence about medical necessity was an additional concern for women who never or sometimes chose CPM. 4. Discussion Most women required their lifetime CBC risk to be more than halved, to 2.5% (from a 5% baseline) or 14% (from a 20% baseline) to justify CPM. Polarised views surrounding CPM were common, with around half of women unwilling to make risk/benefit trade-offs. Specifically, 27% of women consistently chose CPM for no riskreduction. Breast symmetry and fear reduction were influential factors in decision-making, substantiating findings that chest balance [17] and peace of mind [16,38] motivate women's requests for CPM. Clinically, this highlights the importance of discussing less
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Table 1 Participant demographic and disease characteristics. Variable
Age (years) Age at diagnosis (years) Time since diagnosis (years)
Highest educational attainment Incomplete secondary schooling Completed secondary school Non-university tertiary certificate Undergraduate degree Postgraduate degree Martial status Single Married/de facto Widowed Divorced/Separated Undisclosed Continent of birth Australia/New Zealand Europe Asia Africa North/South America ATSIa Background Yes No Language spoken in addition to English Yes No Have offspring Yes No Plans for future offspring Yes No Unsure Dependents Yes No Location of residence Metropolitan city Regional town Rural area Remote area Unilateral breast cancer surgeryb Lumpectomy Mastectomy Mastectomy with reconstruction Bilateral mastectomy Bilateral mastectomy with reconstruction Lymph node surgeryc No Sentinel node biopsy Axillary lymph node dissection Unsure Adjuvant endocrine treatment No Yes N/A (ER negative breast cancer) Unsure Private health insurance No Yes
Did not have CPM (n ¼ 286)
Had CPM (n ¼ 102)
Total (N ¼ 388)
M (SD)
M (SD)
M (SD)
53.7 (8.1) 50.7 (8.1) 3.0 (2.2)
51.7 (8.1) 48.5 (8.6) 3.3 (2.1)
53.2 (8.2) 50.1 (8.3) 3.1 (2.2)
n (%)
n (%)
n (%)
29 31 86 74 66
9 (8.8) 8 (7.8) 34 (33.3) 24 (23.5) 27 (26.5)
38 (9.8) 39 (10.1) 120 (30.9) 98 (25.2) 93 (24.0)
26 (9.1) 229 (80.1) 1 (0.3) 29 (10.1) 1 (0.3)
8 (7.8) 77 (75.5) 0 (0) 17 (16.7) 0 (0)
34 (8.7) 306 (78.9) 1 (0.3) 46 (11.8) 1 (0.3)
245 (85.7) 32 (11.2) 3 (1.0) 3 (1.0) 3 (1.0)
86 (84.3) 14 (13.7) 0 (0) 1 (1.0) 1 (1.0)
331 (85.3) 46 (11.9) 3 (0.8) 4 (1.0) 4 (1.0)
1 (0.3) 285 (99.7)
0 (0) 102 (100)
1 (0.3) 387 (99.7)
17 (5.9) 269 (94.1)
1 (1.0) 101 (99.0)
18 (4.6) 370 (95.4)
223 (78.0) 63 (22.0)
87 (85.3) 15 (14.7)
310 (79.9) 78 (20.1)
5 (1.7) 276 (96.5) 5 (1.7)
0 (0) 101 (99.0) 1 (1.0)
5 (1.3) 377 (97.2) 6 (1.5)
114 (39.9) 172 (60.1)
53 (52.0) 49 (48.0)
167 (43.0) 221 (57.0)
157 (54.0) 78 (27.3) 44 (15.4) 7 (2.4)
61 (59.8) 26 (25.5) 15 (14.7) 0 (0)
218 (56.2) 104 (26.8) 59 (15.2) 7 (1.8)
137 (47.9) 95 (33.2) 48 (16.8) 2 (0.7) 4 (1.4)
1 (1.0) 22 (21.6) 4 (3.9) 31 (30.4) 44 (43.1)
138 (35.6) 117 (30.2) 52 (13.4) 33 (8.5) 48 (12.3)
14 (4.9) 166 (58.0) 104 (36.4) 2 (0.7)
5 (4.9) 50 (49.0) 46 (45.1) 1 (1.0)
19 (4.9) 216 (55.7) 150 (38.7) 3 (0.7)
52 (18.2) 224 (78.3) 9 (3.0) 1 (1.0)
25 (24.5) 72 (70.6) 5 (5.0) 0 (0)
77 (19.8) 296 (76.3) 14 (4.0) 1 (1)
76 (26.6) 210 (73.4)
25 (24.5) 77 (75.5)
101 (26.0) 287 (74.0)
(10.1) (10.8) (30.1) (25.9) (23.1)
a
Aboriginal or Torres Strait Islander Background. 81 women reported having bilateral mastectomy, while 102 women reported having CPM. This discrepancy is likely due to some women reporting unilateral mastectomy as their primary unilateral breast cancer surgery, who later had CPM. c Participants with multiple axillary surgeries are categorised according to the most extensive axillary surgery. b
invasive alternatives for breast symmetry (e.g., breast prostheses) and managing anxiety during clinical consultations to promote informed decision-making. Lowering or eliminating CBC risk was
another primary motive. While this finding may indicate misunderstanding, given their choice offered no risk-reduction, it may also represent a desire to assert control, overcome helplessness and
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Table 2 Participant scores and reliability coefficients (a) for psychosocial and treatment-related variables. Measures
M
SD
Possible Range
Observed Range
Number of Items
Cronbach's a
Psychosocial variables Severity Vulnerability Response Efficacy Self-Efficacy Response Costs Fear of CBCa Screening capability
8.01 6.17 26.63 26.78 22.40 17.40 14.77
1.49 1.72 4.40 5.10 3.76 5.82 3.37
2e10 2e10 7e35 7e35 7e35 0e36 4e20
2e10 2e10 7e35 7e35 8e33 3e32 4e20
2 2 7 7 7 9 4
0.78 0.75 0.77 0.87 0.66 0.78 0.77
Treatment-related variables Breast reconstruction intention
3.78
1.22
1e5
1e5
1
e
a
CBC ¼ Contralateral Breast Cancer.
Fig. 1. Cumulative proportions of women considering whether CPM would be worthwhile for varying reductions in lifetime CBC risk from a (a) 5% baseline and (b) 20% baseline (n ¼ 214). Note: Participants who continually declined CPM (representing 15% of the total sample) are not shown in these graphs.
actively cope with recurrence risk, given similar findings in patient preference studies of adjuvant chemotherapy [39]. Consideration of social-cognitive and psychological factors including emotion regulation, coping styles and cosmetic motives, in addition to
clinical outcomes, thus appears important to comprehensively understand CPM decision-making [18,19]. Approximately 15% of women consistently refused CPM, even if the surgery completely eliminated their CBC risk. Pragmatic factors were most influential in decision-making, including avoiding surgery and complications, and financial/employment concerns, as well as doubts about CPM's medical necessity. Many women would consider CPM only if it more than halved their 5% or 20% CBC risk. This appears larger than the 0.1e2% absolute gains in survival required by early BC patients from 65 to 85% baselines for adjuvant endocrine and chemotherapy, indicated in previous studies employing similar methodology [25,26]. Adjuvant therapies are often recommended to BC patients in standard care and confer a known survival benefit to BRCA1/2 negative women [40], whereas CPM is an invasive surgery offering an unproven survival benefit. These discrepant treatment contexts may explain why women contemplating CPM appear to require greater riskreduction. Risk-reduction also appeared to be one of numerous factors determining the magnitude of benefit required. For example, reducing worry and fear, breast symmetry, circumventing other risk-management strategies and future treatment were other important factors, consistent with literature that cosmetic appearance [16], surveillance difficulties [23] and avoiding preventative strategies [2] motivate CPM decision-making. Minimising discomfort while screening, while communicating the efficacy of screening in detecting CBCs while at an early and potentially curable stage [9], would appear important. Furthermore, as endocrine therapy reduces the risk of metastatic disease and results in improved BC survival and reduced CBC incidence [23], this finding may indicate that women lack understanding of the relative merits of each treatment, reinforcing the need for educational informational resources for patients considering CPM. Previous research implicates younger age, higher education, and intentions for breast reconstruction in predicting CPM uptake [20,41]. Yet we found no association between these characteristics and risk-reduction preferences. Of disease and demographic variables, only prior CPM was associated with preferences, likely reflecting more favourable evaluations of the risk-benefit ratio amongst women who underwent CPM surgery. Cognitive dissonance reduction may have also influenced preferences, whereby women rationalized their satisfaction with CPM to reduce regret and view their decision most positively [42]. Of PMT variables, only coping self-efficacy (encapsulating an individual's capacity to cope with physical changes, surgical complications or costs) influenced the magnitude of risk-reduction required, although only marginally, limiting the clinical significance of this finding.
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Table 3 Demographic, disease and psychosocial variables associated with CPM risk-reduction preferences in bivariate and multivariate analyses. Bivariate analysisa (n ¼ 214)
p
Demographic factors Current age Educationc Marital statusc Current children Plans for future children Dependents Location of residencec
0.098 -0.001 0.035 0.123 -0.007 -0.001 -0.027
0.152 0.990 0.612 0.072 0.921 0.993 0.696
Disease and treatment factors Age at diagnosis Time since diagnosis Current CPM Lymph node surgeryc Adjuvant endocrine treatmentc Private health insurance Reconstruction intention
0.069 0.103 -0.440 -0.023 0.047 0.102 -0.056
0.314 0.132 <0.001*** 0.743 0.493 0.135 0.413
Psychosocial factors Severity Vulnerability Response efficacy Self-efficacy Response costs Screening capability Fear of CBC
-0.167 0.006 -0.321 -0.365 0.276 0.210 -0.151
0.014* 0.925 <0.001*** <0.001*** <0.001*** 0.002** 0.027*
Multivariate analysisb (n ¼ 214)
p
-0.559
<0.001**
-0.014
0.694
-0.023 -0.027 0.019 -0.008 -0.017
0.068 0.018* 0.238 0.639 0.086
a
Data obtained with Pearson's r test. Data obtained with multiple linear regression; unstandardized B values shown. *p < .05,**p < .01,***p < .001. c Variables were dichotomised as follows: Education [university vs. no university qualifications], marital status [married/defacto vs. other], location of residence [metropolitan vs. other], lymph node surgery [sentinel/axillary biopsy vs. no biopsy] and adjuvant endocrine treatment [yes vs. no/unsure]. b
Table 4 Thematic breakdown of five most influential incentives and barriers women considered in CPM decision-making. Always chose CPM (n ¼ 58)
Never chose CPM (n ¼ 31)
Incentives 1. Risk-reduction/elimination
n 53
2. Breast symmetry and balance 3. Reduce worry and fear
38 26
4. Avoid other risk-management strategies
22
5. Breast reconstruction intention
14
Barriers 1. Avoid surgery or post-operative risks/consequences 2. Cost and time off work 3. Physician opposition 4. Pragmatic or health reasons
n 55 27 12 8
5. Breast reconstruction
7
Sometimes chose CPM (n ¼ 125)
1. Risk-reduction/elimination Breast symmetry and balance 2. Reduce worry and fear 3. Actual CBCa or breast scare Extend life expectancy Avoid other risk-management strategies 4. Body-image and appearance Perceived high risk Physician recommendation 5. Doing everything I can
1. Avoid surgery or post-operative risks/consequences 2. Ambivalent about medical necessity 3. Cost and time off work 4. Perceived low risk Self-esteem, body-image and/or femininity 5. Secondary cancer risks higher
n 14
1. Risk-reduction/elimination
n 89
10 5
2. Breast symmetry and balance 3. Reduce worry and fear
60 58
4
4. Avoid other risk-management strategies
34
3
5. Perceived high risk
31
n 26
n 119
22 10 8
1. Avoid surgery or post operative risks/consequences 2. Cost and time off work 3. Ambivalent about medical necessity 4. Perceived low risk
32 31 29
6
5. Risk/benefit ratio insufficient
23
Note: Women were asked to report 3 incentives and 3 barriers for their choice for or against CPM. a CBC ¼ Contralateral breast cancer. n ¼ number of responses.
4.1. Clinical implications Reducing risk influenced decision-making for all women contemplating CPM. However, the magnitude of risk-reduction required varied considerably and polarised preferences were common. Decreasing fear, attaining breast symmetry and avoiding other surveillance and treatment modalities were other frequently cited incentives. Barriers were typically more pragmatic, including anticipating negative surgical consequences, and employment or financial concerns. Given that women may possess inflated views of CPM's impact on their future cancer risk and life expectancy [18,19],
addressing realistic and unrealistic beliefs about CBC risk and CPM survival benefits (if any) [9,16] is important. Women may also developed fixed opinions about prophylactic surgery, thus communication about the likely benefits and risks is critical, particularly the irreversible loss of breast function and sensation [9], and potential for cosmetic dissatisfaction [12]. Given the salience of avoiding screening and other preventative strategies in women's CPM decision-making despite their proven efficacy, further exploration of women's understanding of the relative merits of these treatments is warranted. Integrating these findings with those of existing studies investigating social-cognitive models
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of CPM decision-making, psychological factors beyond physical levels of risk appearing influential in women's CPM decisionmaking, particularly avoiding negative emotional states, situations, and appearance-related concerns [18]. The development of decisional support tools is indicated to improve women's knowledge, reduce decisional conflict [43] and improve supportive care for unilateral BC survivors.
drive women's CPM preferences, and assist women to consider viable alternatives that take into consideration these individual concerns and priorities.
4.2. Sampling and methodological limitations
Disclosure
Several sampling and methodological limitations warrant consideration. While data on Australian CPM rates are lacking, the 26% prevalence of CPM in the present sample was higher than reported by a national US study (12.3%) [3]. Women within cancer networks are generally health-motivated thus pro-CPM views may be overrepresented [44]. Furthermore, this predominantly tertiaryeducated sample may not be representative of the general population with regards to socioeconomic status and health literacy. Non-respondents’ demographic and disease data could not be collected, making it difficult to determine the proportion of women initially contacted who met exclusion criteria (i.e., individuals with BRCA1/2 genes, metastatic cancer or a second primary diagnosis), thus preventing calculation of an accurate non-response rate. Recruitment of a larger sample, diverse in demographic and disease characteristics, may partly mitigate this potential sampling bias. Furthermore, as 47.7% reported having no prior discussion of CPM, this sample was likely to include women unaware of CPM, as well as those already having had or currently contemplating CPM. Prospective sampling in clinical settings, however, is needed to more comprehensively assess women's views around CPM. The use of a hypothetical scenario likely reduced the impact of demographic and disease differences, as women responded to Mary's circumstances. This may explain why younger age and higher education are demographic predictors of CPM uptake in the literature [20], but had little relation to risk-reduction preferences. Qualitative responses, however, suggested that women did apply their own values, beliefs and experiences when responding to the hypothetical scenario. The risk-reduction preference instrument was the last task embedded within a larger questionnaire. The cognitively demanding nature of the task, and questionnaire length, may have decreased participant willingness to complete the survey or certain survey components. Online administration also limited our ability to check understanding, potentially resulting in some women misunderstanding the risk-reduction preference scenarios. Finally, considering CPM decision-making in isolation does not reflect clinical practice, where women are typically presented with multiple cancer-related competing risks (i.e., risk of metastases, local recurrence, CBC), treatment decisions (e.g., breast reconstruction) and risk-management strategies. Future research should explore decisions for CPM considering related curative and preventative treatment decisions.
KAP is an Australian National Breast Cancer Foundation Practitioner Fellow. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.
5. Conclusions The magnitude of risk-reduction women required to make CPM worthwhile varied, although polarized preferences were common. Overall, these findings highlight the need to consider women's attitudes and judgements, beyond objective disease and demographic variables, to holistically understand women's riskmanagement preferences. Preferences for CPM were influenced by appraisals of risk-reduction benefits, as well as attaining breast symmetry, avoiding emotional distress, and perceptions of surgery and other risk-management strategies. Clinicians should accordingly be conscious that factors beyond CBC risk-reduction may
Conflicts of interest None declared.
Ethical approval Ethics approval was granted by the University of Sydney Human Research Ethics Committee (Project Number: 2014/437). Acknowledgements We warmly thank the women who generously dedicated their time to completing this survey. We would also like to thank the administrative staff of Breast Cancer Network Australia and our consumer representatives who provided valuable input into the study. References [1] McDonnell SK, Schaid DJ, Myers JL, et al. Efficacy of contralateral prophylactic mastectomy in women with a personal and family history of breast cancer. J Clin Oncol 2001;19:3938e43. [2] Soran A, Polat AK, Johnson R, McGuire KP. Increasing trend of contralateral prophylactic mastectomy: what are the factors behind this phenomenon? Surgeon 2014;12:316e22. [3] Kurian AW, Lichtensztajn DY, Keegan TH, et al. Use of and mortality after bilateral mastectomy compared with other surgical treatments for breast cancer in California, 1998-2011. JAMA 2014;312:902e14. [4] Meijers-Heijboer H, van Geel B, van Putten WL, et al. Breast cancer after prophylactic bilateral mastectomy in women with a BRCA1 or BRCA2 mutation. N Engl J Med 2001;345:159e64. [5] Metcalfe K, Gershman S, Ghadirian P, et al. Contralateral mastectomy and survival after breast cancer in carriers of BRCA1 and BRCA2 mutations: retrospective analysis. BMJ 2014:348. [6] Narod SA. Bilateral breast cancers. Nat Rev Clin Oncol 2014;11:157e66. [7] Beckmann K, Buckingham J, Craft P, et al. Clinical characteristics and outcomes of bilateral breast cancer in an Australian cohort. Breast 2011;20:158e64. [8] Brenner DJ. Contralateral second breast cancers: prediction and prevention. J Natl Cancer Inst 2010;102:444e5. [9] Lostumbo L, Carbine NE, Wallace J, Ezzo J. Prophylactic mastectomy for the prevention of breast cancer. Cochrane Database Syst Rev 2010:11. [10] Kennecke H, Yerushalmi R, Woods R, et al. Metastatic behavior of breast cancer subtypes. J Clin Oncol 2010;28:3271e7. [11] Barton MB, West CN, Liu I-LA, et al. Complications following bilateral prophylactic mastectomy. J Natl Cancer Inst Monogr 2005;2005:61e6. [12] Frost MH, Hoskin TL, Hartmann LC, et al. Contralateral prophylactic mastectomy: long-term consistency of satisfaction and adverse effects and the significance of informed decision-making, quality of life, and personality traits. Ann Surg Oncol 2011;18:3110e6. [13] Montgomery LL, Tran KN, Heelan MC, et al. Issues of regret in women with contralateral prophylactic mastectomies. Ann Surg Oncol 1999;6:546e52. [14] King TA, Sakr R, Patil S, et al. Clinical management factors contribute to the decision for contralateral prophylactic mastectomy. J Clin Oncol 2011;29: 2158e64. [15] Burke EE, Portschy PR, Tuttle TM. Contralateral prophylactic mastectomy: are we overtreating patients? Expert Rev Anticancer Ther 2014;14:491e4. [16] Rosenberg SM, Tracy MS, Meyer ME, et al. Perceptions, knowledge, and satisfaction with contralateral prophylactic mastectomy among young women with breast cancer: a cross-sectional survey. Ann Intern Med 2013;159:373e81. [17] Beesley H, Holcombe C, Brown SL, Salmon P. Risk, worry and cosmesis in decision-making for contralateral risk-reducing mastectomy: analysis of 60 consecutive cases in a specialist breast unit. Breast 2013;22:179e84. [18] Tesson S, Richards I, Porter D, et al. Women's preferences for contralateral prophylactic mastectomy: an investigation using protection motivation theory. Patient Educ Couns 2016;99:814e22.
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[19] Richards I, Tesson S, Porter D, et al. Predicting women's intentions for contralateral prophylactic mastectomy: an application of an extended theory of planned behaviour. Eur J Oncol Nurs 2016;21:57e65. [20] Yi M, Hunt KK, Arun BK, et al. Factors affecting the decision of breast cancer patients to undergo contralateral prophylactic mastectomy. Cancer Prev Res 2010;3:1026e34. [21] Ashfaq A, McGhan LJ, Pockaj BA, et al. Impact of breast reconstruction on the decision to undergo contralateral prophylactic mastectomy. Ann Surg Oncol 2014:1e7. [22] Baker SK, Mayer DK, Esposito N. The contralateral prophylactic mastectomy decision-making process. Plast Surg Nurs 2013;33:11e21. [23] Murphy JA, Milner TD, O'Donoghue JM. Contralateral risk-reducing mastectomy in sporadic breast cancer. Lancet Oncol 2013;14:e262e9. [24] Blinman P, King M, Norman R, et al. Preferences for cancer treatments: an overview of methods and applications in oncology. Ann Oncol 2012;23(5): 1104e10. [25] Thewes B, Meiser B, Duric VM, et al. What survival benefits do premenopausal patients with early breast cancer need to make endocrine therapy worthwhile? lancet Oncol 2005;6:581e8. [26] Duric V, Stockler M, Heritier S, et al. Patients' preferences for adjuvant chemotherapy in early breast cancer: what makes AC and CMF worthwhile now? Ann Oncol 2005;16:1786e94. [27] Rogers RW. Cognitive and physiological processes in fear appeals and attitude change: a revised theory of protection motivation. Soc Psychophysiol 1983: 153e76. [28] Ralph AF, Ager B, Bell ML, et al. Women's preferences for selective estrogen reuptake modulators: an investigation using the time trade off technique. SpringerPlus 2014;3:264. [29] Hodgkins S, Orbell S. Can protection motivation theory predict behaviour? A longitudinal test exploring the role of previous behaviour. Psychol Health 1998;13:237e50. [30] Helmes AW. Application of the protection motivation theory to genetic testing for breast cancer risk. Prev Med 2002;35:453e62. [31] Institute NC. NCI dictionary of cancer terms. In. http://cancer.gov/dictionary: 2012.
[32] Simes RJ, Coates AS. Patient preferences for adjuvant chemotherapy of early breast cancer: how much benefit is needed? J Natl Cancer Inst Monogr 2001 2001:146e52. [33] Gu C, Chan CW, Twinn S, Choi KC. The influence of knowledge and perception of the risk of cervical cancer on screening behavior in mainland Chinese women. Psycho-Oncology 2012;21:1299e308. [34] Simard S, Savard J. Fear of Cancer Recurrence Inventory: development and initial validation of a multidimensional measure of fear of cancer recurrence. Support Care Cancer 2009;17:241e51. [35] Cohen J. Statistical power analysis for the behavioral sciences. Routledge Acad 2013. [36] Erdfelder E, Faul F, Buchner A. GPOWER: a general power analysis program. Behav Res methods, Instrum Comput 1996;28:1e11. [37] Viera AJ, Garrett JM. Understanding interobserver agreement: the kappa statistic. Fam Med 2005;37:360e3. [38] Musiello T, Bornhammar E, Saunders C. Breast surgeons' perceptions and attitudes towards contralateral prophylactic mastectomy. ANZ J Surg 2012;83: 527e32. [39] Jansen S, Kievit J, Nooij M, et al. Patients' preferences for adjuvant chemotherapy in early-stage breast cancer: is treatment worthwhile? Br J Cancer 2001;84:1577. [40] NIoHCD Panel. National institutes of health consensus development conference statement: adjuvant therapy for breast cancer, November 1e3, 2000. J Natl Cancer Inst 2001;93:979e89. [41] Tuttle TM, Abbott A, Arrington A, Rueth N. The increasing use of prophylactic mastectomy in the prevention of breast cancer. Curr Oncol Rep 2010;12: 16e21. [42] Festinger L. A theory of cognitive dissonance. Stanford University Press; 1962. [43] O'Brien MA, Whelan TJ, Villasis-Keever M, et al. Are cancer-related decision aids effective? A systematic review and meta-analysis. J Clin Oncol 2009;27: 974e85. [44] Meiser B, Butow P, Price M, et al. Attitudes to prophylactic surgery and chemoprevention in Australian women at increased risk for breast cancer. J Womens Health 2003;12:769e78.
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The Breast journal homepage: www.elsevier.com/brst
Original article
Women's preferences for contralateral prophylactic mastectomy following unilateral breast cancer: What risk-reduction makes it worthwhile? Stephanie Tesson a, b, *, Imogen Richards a, David Porter c, Kelly-Anne Phillips d, e, f, g, Nicole Rankin h, Daniel Costa i, Toni Musiello j, Michelle Marven k, Phyllis Butow b, l a
School of Psychology, The University of Sydney, NSW, Australia Psycho-Oncology Co-operative Research Group (PoCoG), The University of Sydney, NSW, Australia Department of Oncology, Auckland Hospital, Auckland, New Zealand d Division of Cancer Medicine, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia e Department of Oncology, Peter MacCallum Cancer Centre, The University of Melbourne, Melbourne, VIC, Australia f Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, Australia g Department of Medicine, St Vincent's Hospital, The University of Melbourne, Melbourne, VIC, Australia h Sydney Catalyst Cancer Translational Cancer Centre, The University of Sydney, NSW, Australia i Pain Management Research Institute, The University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia j University of Western Australia, Perth, WA, Australia k Breast Cancer Network Australia (BCNA), Melbourne, VIC, Australia l Centre for Medical Psychology and Evidence-based Decision-making (CeMPED), The University of Sydney, NSW, Australia b c
a r t i c l e i n f o
a b s t r a c t
Article history: Received 20 July 2016 Received in revised form 23 October 2016 Accepted 30 November 2016
Objectives: Contralateral prophylactic mastectomy (CPM) reduces the risk of contralateral breast cancer (BC) following unilateral BC, but may not increase survival in BRCA1/2 mutation negative women. Despite this, and the risk for adverse physical and psychological impact, uptake is increasing in BRCA1/2 mutation negative women. We aimed to quantify the degree of reduction in lifetime contralateral BC risk women required to justify CPM, and to explore demographic, disease and psychosocial predictors of preferences using Protection Motivation Theory (PMT) as a theoretical framework. Reasoning behind preferences was also examined. Materials and methods: 388 women previously diagnosed with unilateral BC, of negative or unknown BRCA1/2 status, were recruited from an advocacy group research database. Two hypothetical risk tradeoff scenarios were used to quantify the reduction in lifetime contralateral BC risk that women judged necessary to justify CPM, using a 5% and 20% baseline. Demographic, disease and PMT measures were assessed using a questionnaire. Results: Most women required their risk to be more than halved from a 5% or 20% baseline to justify CPM. Polarised preferences were also common, with some women consistently accepting or refusing CPM independent of risk/benefit trade-offs. Preferences were associated with coping self-efficacy and having a prior CPM. Explanations for judging CPM worthwhile included reducing or eliminating contralateral BC risk, attaining breast symmetry and reducing worry. Conclusion: Risk-reduction preferences were highly variable. Decisive factors in women's preferences for CPM related to clinical, psychological and cosmetic outcomes, but not to demographic or disease characteristics. © 2016 Elsevier Ltd. All rights reserved.
Keywords: Breast cancer Contralateral breast cancer Contralateral prophylactic mastectomy Decision-making Patient preferences
1. Introduction * Corresponding author. School of Psychology, Chris O'Brien Lifehouse, Level 6 North (C39Z), The University of Sydney, Camperdown, NSW, 2006, Australia. E-mail address: [email protected] (S. Tesson). http://dx.doi.org/10.1016/j.breast.2016.11.025 0960-9776/© 2016 Elsevier Ltd. All rights reserved.
Women diagnosed with unilateral breast cancer (BC) are increasingly undergoing contralateral prophylactic mastectomy (CPM) worldwide [1,2]. Amongst 1.1 million American BC patients,
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CPM rates rose from 2.0% to 12.3% from 1998 to 2011 [3]. CPM reduces risk of contralateral breast cancer (CBC) [4] and may increase life expectancy for BRCA1/2 carriers, who have a 3e4% annual risk of CBC [5,6]. For women without BRCA1/2 mutations, however, CBC risk is often much lower, estimated in contemporary reports at 0.19e0.5% per annum on average [7,8], and CPM is unlikely to improve life expectancy, thus uptake is controversial. Close surveillance often facilitates early detection and curative treatment of any occurring CBC's [9]. Furthermore, CPM cannot prevent metastatic disease from the first BC, which often poses a substantially higher risk than CBC and principally determines overall survival [10]. CPM carries a risk of postoperative complications [11], and can negatively impact on body image, perceived femininity and sexual intimacy [12], leading to post-surgical regret [13]. Despite this, women without BRCA1/2 mutations are increasingly undergoing CPM. A study of 2695 BC patients reported 24.2% CPM uptake, yet only 13% had documented BRCA1/2 mutations [14], leading to concerns about potential overtreatment without objective medical necessity [15]. Research has explored clinical, demographic and psychological predictors of CPM uptake, including overestimated perceptions of CBC risk and CPM's survival benefit [16], avoidance of future breast surveillance [2,16], and desire for breast symmetry after unilateral mastectomy [17]. Social-cognitive and emotional factors identified as influential in CPM decision-making include women's expectations of positive or negative CPM outcomes, avoiding uncertainty and regret, reducing recurrence-related anxiety, and social norms [17e19]. Demographically, women who are younger, with higher education, Caucasian ethnicity, a family history of BC, and intentions for breast reconstruction, are more likely to undergo CPM [20,21]. However, research has typically focused on high-risk mutation carriers, or failed to identify mutation status [22]. Thus, findings may not generalise to lower-risk women. Reviews highlight the need for more evidence about factors prompting CPM uptake in BRCA1/2 negative women [22,23]. Risk-trade off scenarios provide insight into how patients weigh treatment benefits against treatment harms or inconveniences [24]. Understanding the minimum benefit needed to justify CPM is important to guide ethical, preference-sensitive discussion of CPM. Studies of early BC patients find that many women accept adjuvant endocrine and chemotherapy for 0.1e2% absolute gains in survival [25,26]. Yet no published study has quantified the amount of riskreduction women require to justify CPM. Protection Motivation Theory [27] is a theoretical framework that aims to explain patient preferences, emphasising: perceived: severity and vulnerability to a disease threat, efficacy of a healthprotective behaviour in reducing threat, self-efficacy to undertake the behaviour, and response costs or negative behavioural consequences [27]. PMT has shown utility in explaining intentions for numerous cancer preventative behaviours including adjuvant therapy uptake [28], breast self-examination [29], gene mutation screening [30], and CPM [18]. Accordingly, we aimed to determine the minimum degree of CBC risk-reduction that women of negative or unknown BRCA1/2 status required to justify CPM. We also aimed to identify demographic, clinical and psychosocial predictors of women's riskreduction preferences using PMT as a theoretical framework. Participants reporting greater severity, vulnerability, self-efficacy, response efficacy, and lower response cost scores, were expected to require less risk-reduction.
2. Method 2.1. Participants Participants were members of Breast Cancer Network Australia's (BCNA) Review and Survey Group database. BCNA is Australia's largest BC advocacy organisation, comprising over 110,000 members. Participants were aged 18e70, and had completed primary treatment (i.e., surgery, chemotherapy, radiotherapy) for a unilateral BC diagnosis 0e10 years prior. Participants could be continuing endocrine therapy. Exclusion criteria included: (i) a diagnosis of metastatic or second primary BC, (ii) known BRCA1/2 positive status, and/or (iii) inadequate English language skills to complete the questionnaire. 2.2. Procedure BCNA database members were sent an introductory email including eligibility criteria, a participant information sheet and survey web-link. Individuals could anonymously complete the questionnaire after providing online consent or seek clarification from the research team. Reminder emails were sent twice, two weeks apart. Participants completed demographic and disease items, then read a fact sheet and hypothetical scenario. The fact sheet was based on National Cancer Institute online materials [31], designed in liaison with two medical oncologists, and outlined risks and benefits of different CBC risk-management options (CPM, chemoprevention, hormone therapy, surveillance), to ensure all participants responded with similar knowledge. The hypothetical scenario described a pre-menopausal 48-year-old woman (Mary) diagnosed with early-stage unilateral BC, deliberating her CBC-risk management options after a unilateral mastectomy and chemotherapy. This hypothetical scenario aimed to minimise distress by distancing women from personal treatment decisions. Participants were asked to complete PMT and risk trade-off measures considering Mary's scenario, alongside their own values. 2.3. Measures 2.3.1. Demographic and disease variables Demographic variables assessed included: age, ethnicity, language/s spoken, Aboriginal or Torres Strait Islander background, current children, plans for future children, dependents, marital status, education and residential location. Disease variables included age at unilateral BC diagnosis, primary unilateral BC treatment, lymph node surgery, hormone treatment, private health insurance, CPM status (having had a prior CPM vs. not), and intentions for breast reconstruction if CPM were undertaken. 2.3.2. Risk-reduction preferences Risk-reduction preferences were assessed using two risk tradeoff scenarios adapted from Simes and Coates [32], aiming to determine the minimum degree of risk-reduction required to justify CPM. Participants were asked to sequentially indicate whether they would, or would not, have CPM for increasing degrees of reduction in lifetime CBC risk from a 5% or 20% baseline (the two separate scenarios). These baselines were chosen to cover the range of risks likely in the modern treatment context. For example, in the 5% scenario, participants sequentially indicated whether they would, or would not, have CPM if it reduced their risk from a baseline of 5%e0% (i.e., completely eliminated risk) then to 0.5%, 1%, 1.5% (and so on by 0.5% increments to 5%, at which point CPM offers no risk-reduction). Free-text questions then asked
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participants to list the six primary factors (three incentives, three barriers) influencing their decision-making. 2.3.3. Psychosocial constructs 2.3.3.1. PMT constructs. PMT constructs were assessed using multiitem subscales adapted from other PMT studies or informed by the CPM literature [16,19,33]. Responses were ranked on 5-point Likert scales; subscale scores were generated by summing component subscale items. These measures are discussed in-depth elsewhere [18], and were operationalised as follows: Severity: Two item assessed whether developing CBC would be serious and life threatening. Vulnerability: Two items assessed perceived susceptibility to CBC, based on absolute and comparative risk. Response efficacy: Seven items assessed beliefs about CPM's potential cosmetic, medical and emotional advantages. Self-efficacy: Seven items investigated perceived capability to undergo CPM given certain obstacles. Response costs: Seven items assessed perceptions of CPM's potential disadvantages. 2.3.3.2. Other psychosocial variables. Screening capability (4 items) assessed a woman's ability to continue surveillance, cope with risk, further treatment and breast asymmetry. Fear of CBC was assessed using the 9-item Fear of Cancer Recurrence Inventory Severity subscale [34], examining the frequency and duration of CBC-related thoughts and images, scored on a 5-point scale (0 ¼ Not at all/Never, 4 ¼ A great deal/Several times). 2.3.4. Statistical analysis Descriptive statistics are reported for demographic, disease, psychosocial variables, and risk-reduction preferences (RRP). Two RRPs were computed for each participant; one for the 5% scenario, and one for the 20% scenario. This was calculated by subtracting the risk percentage where a participant switched from indicating a preference for not having to having CPM, from the corresponding 5% or 20% baseline risk. Lower RRPs indicated that participants required less risk-reduction to choose CPM. For example, a score of 0 was assigned to a participant consistently choosing CPM, indicating they required 0% risk-reduction from a 5% or 20% baseline. Scores of 5.0 or 20.0 were assigned to participants who only chose CPM if it completely eliminated risk, requiring 5% or 20% risk-reduction from the corresponding baseline risk. Scores of 5.5 or 22.0 (i.e., 10% of the maximum possible score) were assigned for participants who declined CPM irrespective of benefit, requiring more than the highest risk-reduction possible. The primary outcome variable was calculated by summing the two RRPs for the 5% and 20% scenario together proportionally (i.e., riskreductions of 2.5% from a 5% baseline, and 10% from a 20% baseline were considered equivalent). Inappropriate or inconsistent responses were excluded from analyses. Statistical analyses were conducted using IBM SPSS version 20.0. Associations between demographic, clinical and psychosocial variables and total RRP scores were assessed using Pearson's correlations, with variables correlated at the >0.1 level (p < 0.05) used as predictors in multiple linear regression (MLR) analyses. Categorical independent variables with more than two categories were dichotomised. Assumptions of MLR (i.e., normality, linearity, homogeneity of variance) were satisfied; multicollinearity was not problematic. Assuming 21 predictors in the multivariate models, with a Type 1 error rate of a ¼ 0.05, power ¼ 0.90, and Cohen's [35] standardised regression effect size of f2 ¼ 0.15 (medium effect size), the required sample size was calculated as N ¼ 195 using G-power [36].
235
Categorisation of free-text qualitative responses was undertaken by two independent coders based on thematic similarity, and refined iteratively until unanimous agreement was reached [37]. Responses covering multiple categories were coded twice to retain fidelity to original answers. 3. Results Table 1 shows participant demographic and disease characteristics. Participants included 388 women with a mean age of 53.2 years (SD ¼ 8.2). Most participants were married/de-facto (79%), had children (79%) and attended university (49%). Mean age at diagnosis was 50.1 years (SD ¼ 8.3). Most participants underwent lumpectomy (36%) or unilateral mastectomy without reconstruction (30%) as primary treatment, and received endocrine therapy (76%). Table 2 shows participant scores on PMT and treatmentrelated measures. 3.1. Risk-reduction preferences Fig. 1 illustrates the proportion of participants choosing CPM for various magnitudes of CBC risk-reduction. For the 5% scenario, over half of women judged that a 2.5% risk-reduction was sufficient to make CPM worthwhile. In the 20% scenario, most women required that their risk be reduced to 14% to justify CPM. Approximately 15% of women in both scenarios would never undergo CPM, even if it completely eliminated CBC risk. Furthermore, 27% of women would undergo CPM for no risk-reduction, qualitatively citing non-clinical benefits, discussed below. 3.2. Bivariate correlations and multivariate analysis Bivariate correlations indicated significant associations between RRP and prior CPM status, perceived screening capability, fear of CBC, severity, response efficacy, self-efficacy and response costs (Table 3). In MLR, only prior CPM and self-efficacy remained significant predictors. That is, women with a prior CPM required 0.56% less risk-reduction to justify CPM, on average, than those without a prior CPM. For each one-point increase in coping self-efficacy (M ¼ 26.8, range: 7e35), women required 0.03% less riskreduction, on average, to justify CPM. 3.3. Qualitative responses Content analysis revealed 32 factors (15 incentives, 17 barriers) influencing women's decision-making. Table 4 summarises the five most influential incentives and barriers to undergoing CPM. CBC risk-reduction or elimination was the most frequently cited incentive, alongside breast symmetry and reducing worry or fear. Avoiding surgery and post-operative risks/consequences was the most commonly reported barrier to CPM, alongside financial cost and time off work. Ambivalence about medical necessity was an additional concern for women who never or sometimes chose CPM. 4. Discussion Most women required their lifetime CBC risk to be more than halved, to 2.5% (from a 5% baseline) or 14% (from a 20% baseline) to justify CPM. Polarised views surrounding CPM were common, with around half of women unwilling to make risk/benefit trade-offs. Specifically, 27% of women consistently chose CPM for no riskreduction. Breast symmetry and fear reduction were influential factors in decision-making, substantiating findings that chest balance [17] and peace of mind [16,38] motivate women's requests for CPM. Clinically, this highlights the importance of discussing less
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Table 1 Participant demographic and disease characteristics. Variable
Age (years) Age at diagnosis (years) Time since diagnosis (years)
Highest educational attainment Incomplete secondary schooling Completed secondary school Non-university tertiary certificate Undergraduate degree Postgraduate degree Martial status Single Married/de facto Widowed Divorced/Separated Undisclosed Continent of birth Australia/New Zealand Europe Asia Africa North/South America ATSIa Background Yes No Language spoken in addition to English Yes No Have offspring Yes No Plans for future offspring Yes No Unsure Dependents Yes No Location of residence Metropolitan city Regional town Rural area Remote area Unilateral breast cancer surgeryb Lumpectomy Mastectomy Mastectomy with reconstruction Bilateral mastectomy Bilateral mastectomy with reconstruction Lymph node surgeryc No Sentinel node biopsy Axillary lymph node dissection Unsure Adjuvant endocrine treatment No Yes N/A (ER negative breast cancer) Unsure Private health insurance No Yes
Did not have CPM (n ¼ 286)
Had CPM (n ¼ 102)
Total (N ¼ 388)
M (SD)
M (SD)
M (SD)
53.7 (8.1) 50.7 (8.1) 3.0 (2.2)
51.7 (8.1) 48.5 (8.6) 3.3 (2.1)
53.2 (8.2) 50.1 (8.3) 3.1 (2.2)
n (%)
n (%)
n (%)
29 31 86 74 66
9 (8.8) 8 (7.8) 34 (33.3) 24 (23.5) 27 (26.5)
38 (9.8) 39 (10.1) 120 (30.9) 98 (25.2) 93 (24.0)
26 (9.1) 229 (80.1) 1 (0.3) 29 (10.1) 1 (0.3)
8 (7.8) 77 (75.5) 0 (0) 17 (16.7) 0 (0)
34 (8.7) 306 (78.9) 1 (0.3) 46 (11.8) 1 (0.3)
245 (85.7) 32 (11.2) 3 (1.0) 3 (1.0) 3 (1.0)
86 (84.3) 14 (13.7) 0 (0) 1 (1.0) 1 (1.0)
331 (85.3) 46 (11.9) 3 (0.8) 4 (1.0) 4 (1.0)
1 (0.3) 285 (99.7)
0 (0) 102 (100)
1 (0.3) 387 (99.7)
17 (5.9) 269 (94.1)
1 (1.0) 101 (99.0)
18 (4.6) 370 (95.4)
223 (78.0) 63 (22.0)
87 (85.3) 15 (14.7)
310 (79.9) 78 (20.1)
5 (1.7) 276 (96.5) 5 (1.7)
0 (0) 101 (99.0) 1 (1.0)
5 (1.3) 377 (97.2) 6 (1.5)
114 (39.9) 172 (60.1)
53 (52.0) 49 (48.0)
167 (43.0) 221 (57.0)
157 (54.0) 78 (27.3) 44 (15.4) 7 (2.4)
61 (59.8) 26 (25.5) 15 (14.7) 0 (0)
218 (56.2) 104 (26.8) 59 (15.2) 7 (1.8)
137 (47.9) 95 (33.2) 48 (16.8) 2 (0.7) 4 (1.4)
1 (1.0) 22 (21.6) 4 (3.9) 31 (30.4) 44 (43.1)
138 (35.6) 117 (30.2) 52 (13.4) 33 (8.5) 48 (12.3)
14 (4.9) 166 (58.0) 104 (36.4) 2 (0.7)
5 (4.9) 50 (49.0) 46 (45.1) 1 (1.0)
19 (4.9) 216 (55.7) 150 (38.7) 3 (0.7)
52 (18.2) 224 (78.3) 9 (3.0) 1 (1.0)
25 (24.5) 72 (70.6) 5 (5.0) 0 (0)
77 (19.8) 296 (76.3) 14 (4.0) 1 (1)
76 (26.6) 210 (73.4)
25 (24.5) 77 (75.5)
101 (26.0) 287 (74.0)
(10.1) (10.8) (30.1) (25.9) (23.1)
a
Aboriginal or Torres Strait Islander Background. 81 women reported having bilateral mastectomy, while 102 women reported having CPM. This discrepancy is likely due to some women reporting unilateral mastectomy as their primary unilateral breast cancer surgery, who later had CPM. c Participants with multiple axillary surgeries are categorised according to the most extensive axillary surgery. b
invasive alternatives for breast symmetry (e.g., breast prostheses) and managing anxiety during clinical consultations to promote informed decision-making. Lowering or eliminating CBC risk was
another primary motive. While this finding may indicate misunderstanding, given their choice offered no risk-reduction, it may also represent a desire to assert control, overcome helplessness and
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Table 2 Participant scores and reliability coefficients (a) for psychosocial and treatment-related variables. Measures
M
SD
Possible Range
Observed Range
Number of Items
Cronbach's a
Psychosocial variables Severity Vulnerability Response Efficacy Self-Efficacy Response Costs Fear of CBCa Screening capability
8.01 6.17 26.63 26.78 22.40 17.40 14.77
1.49 1.72 4.40 5.10 3.76 5.82 3.37
2e10 2e10 7e35 7e35 7e35 0e36 4e20
2e10 2e10 7e35 7e35 8e33 3e32 4e20
2 2 7 7 7 9 4
0.78 0.75 0.77 0.87 0.66 0.78 0.77
Treatment-related variables Breast reconstruction intention
3.78
1.22
1e5
1e5
1
e
a
CBC ¼ Contralateral Breast Cancer.
Fig. 1. Cumulative proportions of women considering whether CPM would be worthwhile for varying reductions in lifetime CBC risk from a (a) 5% baseline and (b) 20% baseline (n ¼ 214). Note: Participants who continually declined CPM (representing 15% of the total sample) are not shown in these graphs.
actively cope with recurrence risk, given similar findings in patient preference studies of adjuvant chemotherapy [39]. Consideration of social-cognitive and psychological factors including emotion regulation, coping styles and cosmetic motives, in addition to
clinical outcomes, thus appears important to comprehensively understand CPM decision-making [18,19]. Approximately 15% of women consistently refused CPM, even if the surgery completely eliminated their CBC risk. Pragmatic factors were most influential in decision-making, including avoiding surgery and complications, and financial/employment concerns, as well as doubts about CPM's medical necessity. Many women would consider CPM only if it more than halved their 5% or 20% CBC risk. This appears larger than the 0.1e2% absolute gains in survival required by early BC patients from 65 to 85% baselines for adjuvant endocrine and chemotherapy, indicated in previous studies employing similar methodology [25,26]. Adjuvant therapies are often recommended to BC patients in standard care and confer a known survival benefit to BRCA1/2 negative women [40], whereas CPM is an invasive surgery offering an unproven survival benefit. These discrepant treatment contexts may explain why women contemplating CPM appear to require greater riskreduction. Risk-reduction also appeared to be one of numerous factors determining the magnitude of benefit required. For example, reducing worry and fear, breast symmetry, circumventing other risk-management strategies and future treatment were other important factors, consistent with literature that cosmetic appearance [16], surveillance difficulties [23] and avoiding preventative strategies [2] motivate CPM decision-making. Minimising discomfort while screening, while communicating the efficacy of screening in detecting CBCs while at an early and potentially curable stage [9], would appear important. Furthermore, as endocrine therapy reduces the risk of metastatic disease and results in improved BC survival and reduced CBC incidence [23], this finding may indicate that women lack understanding of the relative merits of each treatment, reinforcing the need for educational informational resources for patients considering CPM. Previous research implicates younger age, higher education, and intentions for breast reconstruction in predicting CPM uptake [20,41]. Yet we found no association between these characteristics and risk-reduction preferences. Of disease and demographic variables, only prior CPM was associated with preferences, likely reflecting more favourable evaluations of the risk-benefit ratio amongst women who underwent CPM surgery. Cognitive dissonance reduction may have also influenced preferences, whereby women rationalized their satisfaction with CPM to reduce regret and view their decision most positively [42]. Of PMT variables, only coping self-efficacy (encapsulating an individual's capacity to cope with physical changes, surgical complications or costs) influenced the magnitude of risk-reduction required, although only marginally, limiting the clinical significance of this finding.
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Table 3 Demographic, disease and psychosocial variables associated with CPM risk-reduction preferences in bivariate and multivariate analyses. Bivariate analysisa (n ¼ 214)
p
Demographic factors Current age Educationc Marital statusc Current children Plans for future children Dependents Location of residencec
0.098 -0.001 0.035 0.123 -0.007 -0.001 -0.027
0.152 0.990 0.612 0.072 0.921 0.993 0.696
Disease and treatment factors Age at diagnosis Time since diagnosis Current CPM Lymph node surgeryc Adjuvant endocrine treatmentc Private health insurance Reconstruction intention
0.069 0.103 -0.440 -0.023 0.047 0.102 -0.056
0.314 0.132 <0.001*** 0.743 0.493 0.135 0.413
Psychosocial factors Severity Vulnerability Response efficacy Self-efficacy Response costs Screening capability Fear of CBC
-0.167 0.006 -0.321 -0.365 0.276 0.210 -0.151
0.014* 0.925 <0.001*** <0.001*** <0.001*** 0.002** 0.027*
Multivariate analysisb (n ¼ 214)
p
-0.559
<0.001**
-0.014
0.694
-0.023 -0.027 0.019 -0.008 -0.017
0.068 0.018* 0.238 0.639 0.086
a
Data obtained with Pearson's r test. Data obtained with multiple linear regression; unstandardized B values shown. *p < .05,**p < .01,***p < .001. c Variables were dichotomised as follows: Education [university vs. no university qualifications], marital status [married/defacto vs. other], location of residence [metropolitan vs. other], lymph node surgery [sentinel/axillary biopsy vs. no biopsy] and adjuvant endocrine treatment [yes vs. no/unsure]. b
Table 4 Thematic breakdown of five most influential incentives and barriers women considered in CPM decision-making. Always chose CPM (n ¼ 58)
Never chose CPM (n ¼ 31)
Incentives 1. Risk-reduction/elimination
n 53
2. Breast symmetry and balance 3. Reduce worry and fear
38 26
4. Avoid other risk-management strategies
22
5. Breast reconstruction intention
14
Barriers 1. Avoid surgery or post-operative risks/consequences 2. Cost and time off work 3. Physician opposition 4. Pragmatic or health reasons
n 55 27 12 8
5. Breast reconstruction
7
Sometimes chose CPM (n ¼ 125)
1. Risk-reduction/elimination Breast symmetry and balance 2. Reduce worry and fear 3. Actual CBCa or breast scare Extend life expectancy Avoid other risk-management strategies 4. Body-image and appearance Perceived high risk Physician recommendation 5. Doing everything I can
1. Avoid surgery or post-operative risks/consequences 2. Ambivalent about medical necessity 3. Cost and time off work 4. Perceived low risk Self-esteem, body-image and/or femininity 5. Secondary cancer risks higher
n 14
1. Risk-reduction/elimination
n 89
10 5
2. Breast symmetry and balance 3. Reduce worry and fear
60 58
4
4. Avoid other risk-management strategies
34
3
5. Perceived high risk
31
n 26
n 119
22 10 8
1. Avoid surgery or post operative risks/consequences 2. Cost and time off work 3. Ambivalent about medical necessity 4. Perceived low risk
32 31 29
6
5. Risk/benefit ratio insufficient
23
Note: Women were asked to report 3 incentives and 3 barriers for their choice for or against CPM. a CBC ¼ Contralateral breast cancer. n ¼ number of responses.
4.1. Clinical implications Reducing risk influenced decision-making for all women contemplating CPM. However, the magnitude of risk-reduction required varied considerably and polarised preferences were common. Decreasing fear, attaining breast symmetry and avoiding other surveillance and treatment modalities were other frequently cited incentives. Barriers were typically more pragmatic, including anticipating negative surgical consequences, and employment or financial concerns. Given that women may possess inflated views of CPM's impact on their future cancer risk and life expectancy [18,19],
addressing realistic and unrealistic beliefs about CBC risk and CPM survival benefits (if any) [9,16] is important. Women may also developed fixed opinions about prophylactic surgery, thus communication about the likely benefits and risks is critical, particularly the irreversible loss of breast function and sensation [9], and potential for cosmetic dissatisfaction [12]. Given the salience of avoiding screening and other preventative strategies in women's CPM decision-making despite their proven efficacy, further exploration of women's understanding of the relative merits of these treatments is warranted. Integrating these findings with those of existing studies investigating social-cognitive models
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239
of CPM decision-making, psychological factors beyond physical levels of risk appearing influential in women's CPM decisionmaking, particularly avoiding negative emotional states, situations, and appearance-related concerns [18]. The development of decisional support tools is indicated to improve women's knowledge, reduce decisional conflict [43] and improve supportive care for unilateral BC survivors.
drive women's CPM preferences, and assist women to consider viable alternatives that take into consideration these individual concerns and priorities.
4.2. Sampling and methodological limitations
Disclosure
Several sampling and methodological limitations warrant consideration. While data on Australian CPM rates are lacking, the 26% prevalence of CPM in the present sample was higher than reported by a national US study (12.3%) [3]. Women within cancer networks are generally health-motivated thus pro-CPM views may be overrepresented [44]. Furthermore, this predominantly tertiaryeducated sample may not be representative of the general population with regards to socioeconomic status and health literacy. Non-respondents’ demographic and disease data could not be collected, making it difficult to determine the proportion of women initially contacted who met exclusion criteria (i.e., individuals with BRCA1/2 genes, metastatic cancer or a second primary diagnosis), thus preventing calculation of an accurate non-response rate. Recruitment of a larger sample, diverse in demographic and disease characteristics, may partly mitigate this potential sampling bias. Furthermore, as 47.7% reported having no prior discussion of CPM, this sample was likely to include women unaware of CPM, as well as those already having had or currently contemplating CPM. Prospective sampling in clinical settings, however, is needed to more comprehensively assess women's views around CPM. The use of a hypothetical scenario likely reduced the impact of demographic and disease differences, as women responded to Mary's circumstances. This may explain why younger age and higher education are demographic predictors of CPM uptake in the literature [20], but had little relation to risk-reduction preferences. Qualitative responses, however, suggested that women did apply their own values, beliefs and experiences when responding to the hypothetical scenario. The risk-reduction preference instrument was the last task embedded within a larger questionnaire. The cognitively demanding nature of the task, and questionnaire length, may have decreased participant willingness to complete the survey or certain survey components. Online administration also limited our ability to check understanding, potentially resulting in some women misunderstanding the risk-reduction preference scenarios. Finally, considering CPM decision-making in isolation does not reflect clinical practice, where women are typically presented with multiple cancer-related competing risks (i.e., risk of metastases, local recurrence, CBC), treatment decisions (e.g., breast reconstruction) and risk-management strategies. Future research should explore decisions for CPM considering related curative and preventative treatment decisions.
KAP is an Australian National Breast Cancer Foundation Practitioner Fellow. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.
5. Conclusions The magnitude of risk-reduction women required to make CPM worthwhile varied, although polarized preferences were common. Overall, these findings highlight the need to consider women's attitudes and judgements, beyond objective disease and demographic variables, to holistically understand women's riskmanagement preferences. Preferences for CPM were influenced by appraisals of risk-reduction benefits, as well as attaining breast symmetry, avoiding emotional distress, and perceptions of surgery and other risk-management strategies. Clinicians should accordingly be conscious that factors beyond CBC risk-reduction may
Conflicts of interest None declared.
Ethical approval Ethics approval was granted by the University of Sydney Human Research Ethics Committee (Project Number: 2014/437). Acknowledgements We warmly thank the women who generously dedicated their time to completing this survey. We would also like to thank the administrative staff of Breast Cancer Network Australia and our consumer representatives who provided valuable input into the study. References [1] McDonnell SK, Schaid DJ, Myers JL, et al. Efficacy of contralateral prophylactic mastectomy in women with a personal and family history of breast cancer. J Clin Oncol 2001;19:3938e43. [2] Soran A, Polat AK, Johnson R, McGuire KP. Increasing trend of contralateral prophylactic mastectomy: what are the factors behind this phenomenon? Surgeon 2014;12:316e22. [3] Kurian AW, Lichtensztajn DY, Keegan TH, et al. Use of and mortality after bilateral mastectomy compared with other surgical treatments for breast cancer in California, 1998-2011. JAMA 2014;312:902e14. [4] Meijers-Heijboer H, van Geel B, van Putten WL, et al. Breast cancer after prophylactic bilateral mastectomy in women with a BRCA1 or BRCA2 mutation. N Engl J Med 2001;345:159e64. [5] Metcalfe K, Gershman S, Ghadirian P, et al. Contralateral mastectomy and survival after breast cancer in carriers of BRCA1 and BRCA2 mutations: retrospective analysis. BMJ 2014:348. [6] Narod SA. Bilateral breast cancers. Nat Rev Clin Oncol 2014;11:157e66. [7] Beckmann K, Buckingham J, Craft P, et al. Clinical characteristics and outcomes of bilateral breast cancer in an Australian cohort. Breast 2011;20:158e64. [8] Brenner DJ. Contralateral second breast cancers: prediction and prevention. J Natl Cancer Inst 2010;102:444e5. [9] Lostumbo L, Carbine NE, Wallace J, Ezzo J. Prophylactic mastectomy for the prevention of breast cancer. Cochrane Database Syst Rev 2010:11. [10] Kennecke H, Yerushalmi R, Woods R, et al. Metastatic behavior of breast cancer subtypes. J Clin Oncol 2010;28:3271e7. [11] Barton MB, West CN, Liu I-LA, et al. Complications following bilateral prophylactic mastectomy. J Natl Cancer Inst Monogr 2005;2005:61e6. [12] Frost MH, Hoskin TL, Hartmann LC, et al. Contralateral prophylactic mastectomy: long-term consistency of satisfaction and adverse effects and the significance of informed decision-making, quality of life, and personality traits. Ann Surg Oncol 2011;18:3110e6. [13] Montgomery LL, Tran KN, Heelan MC, et al. Issues of regret in women with contralateral prophylactic mastectomies. Ann Surg Oncol 1999;6:546e52. [14] King TA, Sakr R, Patil S, et al. Clinical management factors contribute to the decision for contralateral prophylactic mastectomy. J Clin Oncol 2011;29: 2158e64. [15] Burke EE, Portschy PR, Tuttle TM. Contralateral prophylactic mastectomy: are we overtreating patients? Expert Rev Anticancer Ther 2014;14:491e4. [16] Rosenberg SM, Tracy MS, Meyer ME, et al. Perceptions, knowledge, and satisfaction with contralateral prophylactic mastectomy among young women with breast cancer: a cross-sectional survey. Ann Intern Med 2013;159:373e81. [17] Beesley H, Holcombe C, Brown SL, Salmon P. Risk, worry and cosmesis in decision-making for contralateral risk-reducing mastectomy: analysis of 60 consecutive cases in a specialist breast unit. Breast 2013;22:179e84. [18] Tesson S, Richards I, Porter D, et al. Women's preferences for contralateral prophylactic mastectomy: an investigation using protection motivation theory. Patient Educ Couns 2016;99:814e22.
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