Knowledge and preference for breast conservation therapy among women without breast cancer

Article Knowledge and Preference for Breast Conservation Therapy among Women Without Breast Cancer DeAnn Lazovich, PhD*‡ Kristin K. Raab, MPH* James G. Gurney, PhD*†‡ Hegang Chen, PhD*‡ *Division of Epidemiology School of Public Health †Division of Epidemiology/Clinical Research Department of Pediatrics ‡University of Minnesota Cancer Center University of Minnesota Minneapolis, Minnesota

Abstract We interviewed 419 adult women in Minnesota, who were selected at random and without a history of breast cancer, to ascertain what percentage could correctly report that cure was the same for breast conservation therapy and mastectomy, what percentage would state a preference for breast conservation therapy rather than mastectomy, and characteristics associated with these outcomes. Nearly all women (n ⫽ 360; 86%) had heard of both mastectomy and breast conservation therapy; among these women, 37% correctly reported that the two treatments were equally efficacious. Given a scenario where they were diagnosed with breast cancer amenable to either treatment, 58% of participants stated a preference for breast conservation therapy. Older women were less likely than younger women to know that cure was the same for breast conservation therapy and mastectomy (adjusted OR ⫽ 0.5, 95% CI 0.2, 1.0), and women residing in urban areas were more likely to prefer breast conservation therapy over mastectomy compared to rural residents (adjusted OR ⫽ 2.2, 95% CI 1.3, 3.8). Comparing these findings to women diagnosed with breast cancer in Minnesota, breast conservation therapy was found to be performed less frequently than preference for such therapy among women in our study would suggest. Educating women prior to diagnosis about breast cancer treatment options, and exploring reasons for the gap between actual utilization of breast conservation therapy and prediagnosis preference, may be indicated.

I

n 1990, a National Institutes of Health Consensus Development Conference1 recommended breast conservation therapy, rather than mastectomy, for the majority of women with Stage I or II invasive breast cancer. This recommendation was based on numerous randomized controlled trials that demonstrated equivalent survival for women with either type of surgery.2–7 In addition to certain disease characteristics to determine eligibility for breast conservation therapy, the Conference acknowledged the importance

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of a woman’s preference for type of surgery when making the surgical treatment decision. Studies to evaluate women’s choice of surgery have typically been conducted after breast cancer surgery;8 –13 there are no recent studies which have sought to learn what women without breast cancer know about the disease and its treatment. Consequently, we undertook a crosssectional study of women without breast cancer to evaluate their knowledge of surgical options for breast cancer and their preference for breast conservation therapy or mastectomy should they ever face such an experience. Although we acknowledge that women may feel differently about treatment preference if diagnosed with breast cancer, such information may be helpful to clinicians to understand women’s knowledge and perceptions about breast cancer surgery, which may be brought to discussions about surgical treatment options.

METHODS The University of Minnesota conducts an annual statewide telephone survey on a range of special interest topics. The survey sample consists of households selected randomly from all Minnesota telephone exchanges. Selection procedures guarantee that every telephone household in the state has an equal chance to be included in the survey and once the household is sampled, every adult has an equal chance to be included. A total of 2,488 telephone exchanges were initially called for the 1998 survey. Of these, 978 (40%) were eliminated due to being nonworking or nonhousehold numbers. Among identified households, 40 were ineligible due to a physical or language problem. Among the 1,470 remaining households, 7% were not reached after 6 or more attempts, 38% declined to participate (reasons unknown), and 55%, men and women, agreed to be interviewed. Men were not asked questions pertaining to breast cancer treatment. Of the 430 women respondents, we excluded 11 who reported a history of breast cancer. We asked the remaining women (n ⫽ 419) questions about whether they had ever heard of mastectomy or breast conservation therapy. Only those women who had heard of both procedures (n ⫽ 360; 86%) were asked what they knew about the comparative efficacy of the two treatments, the total number of their friends and relatives with breast cancer, how many of them had undergone mastectomy (as an indicator of social influence on treatment decisions), which surgery they would choose if they were ever diagnosed with breast cancer, and the reasons for their choice (an open-ended response with up to three reasons). We also collected information on age, race, income, education, martial status, county of residence, and past history of mammography for all study participants. We classified women as knowledgeable about the efficacy of breast conservation therapy relative to mastectomy if they reported that the two treatments were equally likely to result in cure. Before asking women about their preference for type of surgery, we provided them with a scenario in which they had been diagnosed with breast cancer and their physician told them they had a choice between breast conservation therapy or mastectomy. We then compared women who stated a preference for breast conservation therapy to those who would choose mastectomy. The small percentage of women (13%) who elected an alternative therapy or who did not know which treatment they would choose were excluded from this comparison. We examined whether the likelihood that women had accurate knowledge about efficacy of the surgical options, relative to those who did not, was associated with age, marital status, residence in an urban or rural region, education, income, prior mammography, or the treatment experience of friends or relatives with breast cancer (either no friends or relatives with breast

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cancer, or among those with breast cancer, the proportion who had mastectomy). We similarly assessed the likelihood that women preferred breast conservation therapy versus mastectomy for these same characteristics. We included all women, regardless of race, in our analyses. However, due to the small proportion of women who were non-Caucasian (7.2%), we were unable to examine the associations between race and our outcomes of interest. We used logistic regression14 to calculate odds ratios (OR) and 95% confidence intervals (CI) for each of these associations, while controlling for age, residence, education, and income, unless one of these potential confounders was the factor of interest, in which case the ORs were adjusted for the other three.

RESULTS Among the 86% of women who had heard of both treatment options, 37% accurately reported that the two treatments were equally efficacious. The remaining women either did not know how the treatments compared (23%) or responded that one or the other treatment was superior (40%). After hearing the breast cancer scenario, 58% (95% CI 53– 63%) of women stated a preference for breast conservation therapy. This percentage did not vary by their prior knowledge of the efficacy of the two treatments. The primary two reasons women listed for choosing breast conservation therapy were to preserve the breast (52%) and/or to have less aggressive treatment (46%). Among women who preferred mastectomy over breast conservation therapy, 41% expressed fear of recurrence, 27% would not want radiation, and 17% would choose mastectomy because of the experience of others. Relative to younger women (Table 1), women age 65 or older were less likely to report that the two treatments provided equivalent cure rates (adjusted OR ⫽ 0.5, 95% CI 0.2, 1.0) and were somewhat less likely to prefer breast conservation therapy than mastectomy (adjusted OR ⫽ 0.8, 95% CI 0.4, 1.6). Women residing in an urban area of the state appeared to be more familiar than women in rural regions that breast conservation therapy was equal to mastectomy for curing breast cancer (adjusted OR ⫽ 1.4, 95% CI 0.8, 2.3), and they strongly preferred breast conservation therapy relative to mastectomy (adjusted OR ⫽ 2.2, 95% CI 1.3, 3.8). Neither knowledge nor preference varied among women according to the percentage of their friends or relatives who had been treated by mastectomy compared with women who had no such personal experience. No discernable patterns for knowledge or preference were observed with marital status, education, income, or prior mammography.

86% of women respondents had . . . heard of mastectomy and breast conservation therapy

DISCUSSION The National Cancer Institute last surveyed women without breast cancer almost 20 years ago,15 and we could find only one other report16 in which women without breast cancer were queried about breast cancer treatment preferences. Although these now dated reports preceded major changes in breast cancer treatment, our findings are remarkably consistent for the percentage of women who had heard of mastectomy, the percentage who would worry about breast cancer recurrence, if diagnosed, and the percentage who would choose breast conservation therapy. A finding unique to our study is that most women had heard of breast conservation therapy, yet only 37% reported that the treatment was as efficacious as mastectomy for cure of breast cancer. Interestingly, we found that few demographic characteristics were strongly associated with either knowledge about the efficacy of breast conser212

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37% accurately reported that the two treatments were equally efficacious

Table 1. CHARACTERISTICS ASSOCIATED WITH KNOWLEDGE OF OR PREFERENCE FOR BREAST CONSERVATION THERAPY AMONG HEALTHY WOMEN IN MINNESOTA Knowledge* (n ⫽ 360)

Characteristics

Age (years) ⬍50 50–64 65⫹ Marital status Married Single, divorced, or separated Widowed Residence Rural Urban Education ⱕHigh school Some college College degree Income ⬍$35,000 $35,000–59,000 $60,000⫹ Ever had mammogram Yes No Surgical experience of friends/ relatives with breast cancer None with cancer ⬍50% had mastectomy 50%⫹ had mastectomy

Preference† (n ⫽ 312)

N‡

% Preferred Breast Conservation Therapy

Adj. OR§

95% CI

(0.4, 1.4) (0.2, 1.0)

185 62 65

69 73 57

1.0 1.5 0.8

(0.7, 3.1) (0.4, 1.6)

1.0 1.0 0.7

(0.5, 1.8) (0.3, 1.8)

187 89 34

65 74 65

1.0 2.0 1.8

(1.0, 4.1) (0.7, 5.0)

34 38

1.0 1.4

(0.8, 2.3)

139 173

60 73

1.0 2.2

(1.3, 3.8)

115 130 113

34 39 37

1.0 0.9 0.7

(0.5, 1.6) (0.4, 1.5)

97 116 99

58 69 73

1.0 1.7 1.6

(0.9, 3.3) (0.7, 3.3)

115 111 82

34 43 34

1.0 1.3 0.8

(0.7, 2.3) (0.4, 1.6)

103 100 72

64 66 74

1.0 0.8 0.9

(0.4, 1.6) (0.4, 2.0)

232 128

32 44

1.0 1.5

(0.9, 2.6)

202 110

69 36

1.0 0.7

(0.4, 1.3)

90 66 184

33 41 39

1.0 1.2 1.1

(0.6, 2.4) (0.6, 2.0)

80 58 160

65 71 66

1.0 1.1 1.2

(0.5, 2.3) (0.6, 2.2)

N‡

% Knowledgeable

Adj. OR§

95% CI

208 70 82

41 36 26

1.0 0.8 0.5

216 96 41

39 40 22

167 193

*Knowledge defined as the percentage of women who reported that breast conservation therapy and mastectomy were equally efficacious for treatment of breast cancer. †Preference defined as the percentage of women who stated a preference for breast conservation therapy rather than mastectomy. ‡Column totals may not equal total N due to missing data for some characteristics. §Adjusted for age, residence, education, income. Abbreviations: OR ⫽ odds ratio; CI ⫽ confidence interval.

vation therapy relative to mastectomy or preference for such treatment. We hypothesized that one reason the majority of women undergo mastectomy is that the procedure is familiar and perceived to be standard treatment for breast cancer. If this were true, we would have expected that knowledge and preference for breast conservation therapy would depend upon a respondent’s experience with breast cancer and its treatment among her friends and relatives. We found no association, however, with either outcome. The strongest associations with knowledge and preference for breast conservation therapy were for age and residence: with increasing age, women were less able to correctly report how the efficacy of the two surgical options compared and older women tended to be less likely to prefer breast conservation therapy relative to younger women, whereas women in an urban region were much more likely to prefer breast conservation therapy than residents of rural areas. These findings are consistent with what is known about utilization of breast conservation therapy among women with breast cancer.13,17–22

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Because it has been suggested that women’s treatment preference may be a factor in the variation in utilization of breast conservation therapy observed nationally,22 we were curious about how our results compared to treatment of women diagnosed with breast cancer in Minnesota. Subsequently, we obtained data from the Minnesota Cancer Surveillance System for all women diagnosed with American Joint Commission on Cancer (AJCC)23 Stage I or II breast cancer in 1996, the most recent year for which data were available. Overall, 36.2% of women with Stage I or II breast cancer underwent breast conservation therapy in that year, a figure lower than the percentage of sampled women stating a preference for such treatment (58%) in our 1998 survey. Among women with breast cancer residing in urban areas, 41% underwent breast conservation therapy compared with 32% of such women in rural areas, and use of the procedure was greater among breast cancer cases under age 65 (43%) compared with those who were older (27%). For each of these subgroups, however, preference for breast conservation therapy among women without breast cancer exceeded the frequency with which breast conservation therapy was performed. It has been estimated in one study24 that approximately 20% of women with Stage I or II breast cancer may be ineligible for breast conservation therapy; taking eligibility into account, the frequency of breast conservation therapy would still fall below preference for such therapy among women in our study. These data raise interesting questions on whether a substantial number of women are undergoing surgical treatment for breast cancer that is inconsistent with their prediagnosis treatment preference or whether women feel differently about the surgery they prefer, once confronted with a breast cancer diagnosis. Similar to what has been reported for women with breast cancer,8,13 women without breast cancer would choose mastectomy out of fear of recurrence whereas 27% would opt for mastectomy to avoid radiation. In reviewing the open-ended responses from our participants choosing mastectomy, a commonly expressed theme was that a mastectomy would “get rid of all the cancer.” Based on the trials, however, women with mastectomy are just as likely to experience a local recurrence on the chest wall as women with breast conservation therapy are likely to have a recurrence in the breast.2–7 It is not clear to what extent women with or without breast cancer understand this fact and how this knowledge might affect their decision. Furthermore, having a mastectomy apparently does not mitigate concerns about cancer recurrence—in a recent meta-analysis of 40 quality-of-life studies among breast cancer patients12 it was concluded that women undergoing mastectomy were more likely to experience cancer-related fears and concerns after surgery than those with breast conservation therapy. Unfortunately, we could not discern from the open-ended responses the precise reasons that women did not want radiation therapy. In general, they simply stated that they would not want such treatment. Although survey respondents were similar to Minnesota census estimates for age, gender, and residence, only 55% of individuals in eligible households completed the survey. Consequently, some of our results could be biased if respondents differed from nonrespondents on their knowledge of or preference for breast cancer surgery for the characteristics we examined. However, since potential participants were informed in an introductory letter that the survey concerned education, quality of life, and the environment, but did not specifically mention breast cancer, differences between those who did or did not participate seem unlikely for our particular focus. A strength of our study is that it represents women’s knowledge and preference for breast conservation therapy unaffected by the presence of disease or a physician’s treatment recommendation. In summary, almost all women in our sample population know that breast 214

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58% stated a preference for breast conservation therapy

conservation therapy exists but most do not know how it compares to mastectomy as a treatment choice and they state a preference for breast conservation therapy more frequently than it is performed in Minnesota. Our results could be interpreted to suggest that women need to be better informed prior to a diagnosis of breast cancer to better equip them for participation in future treatment decisions. The reasons for an apparent gap between the level of breast conservation therapy performed in Minnesota and women’s prediagnosis preference for such treatment deserve further exploration, to ensure that women diagnosed with breast cancer receive treatment consistent with their preference, as recommended by the National Institutes of Health Consensus Development Conference.

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