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Relationships of mood disturbance and social support to symptom experience in Korean women with breast cancer
Vol. 27 No. 5 May 2004
Journal of Pain and Symptom Management
425
Original Article
Relationships of Mood Disturbance and Social Support to Symptom Experience in Korean Women with Breast Cancer Eun-Hyun Lee, PhD, RN, Bok Yae Chung, PhD, RN, Hee Boog Park, PhD, MD, and Ki Hong Chun, PhD, MD School of Medicine, Ajou University (E.-H.L., H.B.P., K.H.C.), Suwon; and Division of Nursing (B.Y.C.), Kyungpook National University, Taegu, South Korea
Abstract The purpose of this study was to identify how mood disturbance and social support were related to the symptoms experienced by Korean women with breast cancer. A cross-sectional, correlational design was used for the study. A convenience sample of 134 Korean women receiving chemotherapy for breast cancer was recruited. The participants completed questionnaires on symptom experience using the Symptom Experience Scale, mood disturbance using the Linear Analogue Self-Assessment Scale, and social support using the Social Support Scale. Mood disturbance and social support had a significant interaction effect on symptom experience. A higher level of mood disturbance led to a higher level of symptoms when the level of social support was average or low, which implies that clinical interventions for attenuating the impact of mood disturbance on symptom experience might be effective only for women perceiving average or low levels of social support. J Pain Symptom Manage 2004;27:425–433. 쑖 2004 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Breast cancer, symptom experience, mood disturbance, social support, interaction effect
Introduction In the past, the low prevalence of breast cancer in Asia led to the condition being considered a ‘Western affliction.’ However, in recent times, the number of Korean women diagnosed with breast cancer has increased rapidly. According to the Korean Ministry of Health and Welfare,1 breast cancer is now the most common type of cancer in Korean women.
Address reprint requests to: Eun-Hyun Lee, PhD, RN, Ajou University School of Medicine, San 5, WonchonDong, Paldal-Gu, Suwon 442-721, South Korea. Accepted for publication: October 6, 2003.
쑖 2004 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved.
The primary treatment for breast cancer involves surgery. Based upon surgical findings and pathology, adjuvant treatment such as radiation therapy or chemotherapy is given.2 In many breast cancer patients, adjuvant chemotherapy has side effects of multiple symptoms which interfere with daily activities,3 social independence,4 self-care,5 adjustment,6 and quality of life.7 Considering their negative impact, symptoms are a major focus in the care of patients with breast cancer. In their theory of unpleasant symptoms (TOUS), Lenz et al.8 characterized symptoms as the perceived indicators of change in normal functioning, as experienced by patients. Symptoms can occur alone or in isolation from each 0885-3924/04/$–see front matter doi:10.1016/j.jpainsymman.2003.10.007
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other, but in many cases multiple symptoms are experienced simultaneously. Symptoms are also characterized as consisting of common shared dimensions—such as frequency, intensity, and distress—across symptoms that are not limited to one symptom. Women with breast cancer, especially those undergoing adjuvant therapy, experience multiple adverse symptoms such as nausea, vomiting, fatigue, anorexia, and hair loss.9 Some investigators have reported that nausea and vomiting can occur more than 24 hours after chemotherapy in 60–80% of patients.10,11 Portenoy et al. reported that the most frequently experienced symptoms in 297 patients with cancer (of whom 32% had breast cancer) were lack of energy, lack of appetite, and pain.12 In a one-year longitudinal study of 93 breast cancer patients, Hoskins, Budin, and Maislin13 found that fatigue was a common experience that prevailed throughout the recovery period from 30 days to 6 months postsurgery, but was relieved after one year. Nausea, vomiting, and hair loss were also present from approximately 30 days to 6 months. Meyerowitz, Watkins, and Sparks14 interviewed 50 women during treatment with adjuvant chemotherapy for breast cancer, and reported fatigue, nausea, and irritability as the most distressing symptoms. Hair loss is also reported as one of the most upsetting experiences for women undergoing chemotherapy for breast cancer.2 It is, therefore, clear that women with breast cancer experience multiple unpleasant symptoms related to chemotherapy. The TOUS8 noted that psychological and situational factors directly influence the symptoms that patients experience. Psychological factors refer to mood, the affective reaction to illness, and the degree of uncertainty and knowledge about the symptoms and their meaning. Various psychological issues are associated with breast cancer and its treatment, of which mood disturbance (such as anxiety and depression) has been noted as a serious psychological problem. Some investigators have stated that many women with breast cancer experience mild to severe forms of anxiety, depression, hostility, sadness, frustration, and anger as responses to the disease and its treatment.15,16 In the study by Cimprich17 on women newly diagnosed with breast cancer, mood disturbance was significantly correlated with the number of
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symptoms experienced (r ⫽ 0.65, P ⬍ 0.01). In a similar vein, Piper demonstrated that the intensity and frequency of fatigue was moderately correlated with mood disturbance in women with breast cancer.18 Situational factors in the TOUS8 refer to aspects of the social environment, such as social support, and of the physical environment, such as noise and light. In women with breast cancer, social support has emerged as an important situational resource that can relieve symptoms,7 because patients tend to feel better when social support is available.19,20 Social support has been broadly defined as the resources provided by others.21 The term social support is often specified by its source components, such as kinship, the professional network, and the community.22,23 In their qualitative studies, Jun24 and Chung25 noted that family members are pivotal in supporting Korean women with breast cancer, and healthcare professionals are also an important source of support, especially during the period of adjuvant treatment for breast cancer. In the study by Budin6 involving 101 unmarried women with breast cancer, perceived social support was related to symptom distress (r ⫽ ⫺0.22, P ⬍ 0.01), which is a dimension of symptom experience. Lenz et al. also asserted that the psychological and situational factors in the TOUS8 are related to each other, and that these factors interact in their correlation with symptom experience. In 93 Korean women undergoing chemotherapy for breast cancer, it was found that family support was negatively related with anxiety (r ⫽ ⫺0.23, P ⬍ 0.05).26 Similarly, in a study on Korean patients receiving chemotherapy or radiation therapy, Tae27 reported that perceived professional medical support was significantly and negatively related to depression (r ⫽ ⫺0.15, P ⬍ 0.001). Although a negative relationship between social support and mood disturbance in women with breast cancer has been reported, the interaction effect of social support and mood disturbance on symptom experience has never been tested. Based upon the TOUS and a literature review on breast cancer, the purpose of this study was to identify the relationships of mood disturbance and social support on the symptom experience of women undergoing chemotherapy for breast cancer. The specific hypotheses were as follows: 1) there will be a direct relationship of
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mood disturbance to symptom experience; 2) there will be a direct relationship of social support to symptom experience; 3) there will be a negative relationship between social support and mood disturbance; and 4) there will be an interaction effect of mood disturbance and social support on symptom experience.
Methods Design and Sample A cross-sectional, correlational design was used to examine the relationships of mood distribution and social support to symptom experience in Korean women with breast cancer. The convenience sample used in this study comprised 134 women with a diagnosis of breast cancer who were undergoing adjuvant chemotherapy, prescribed antiemetic medicine, over 18 years of age, and literate in Korean. Based upon the guideline by Cohen,28 the sample size met the requirement for a Pearson’s correlation analysis to detect a medium effect size (r ⫽ 0.30) at an alpha of 0.05 with a statistical power of 0.8, and for a multiple regression analysis with two predictors and one cross-product term (mood disturbance ⫻ social support) to detect a medium effect size (f 2 ⫽ 0.15) at an alpha of 0.05 with a statistical power of 0.8. Table 1 presents the general characteristics and medical information of the sample population. The age ranged from 26 years to 69 years, with a mean of 45.29 years (SD ⫽ 8.75). Most of the subjects were married (84.3%), had at least a high school degree (66.4%), and were predominantly Buddhist (37.3%) or Protestant (25.4%). The monthly income of 49 of the women (36.6%) was 1,000,000–1,999,999 South Korean won (US$ 830–1,670). Ninety-three women (69.4%) had received a modified radical mastectomy, and approximately two-thirds of the sample had Stage II breast cancer.
Instruments Symptom experience was measured using the Symptom Experience Scale (SES).29 The SES has never been applied to a Korean population, and thus it was translated into Korean using a back-translation technique which is the most common and highly recommended procedure for translating such an instrument.30,31 The SES was first translated from English into Korean
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Table 1 General Characteristics and Medical Information (n ⫽ 134) Variable Age (years) 26–29 30–39 40–49 50–59 60–69 Marital status Single, never married Married Divorced Widow Separated Missing Education completed Elementary school Middle school High school Baccalaureate degree and over Missing Religion Buddhist Protestant Roman Catholic None Missing Monthly incomea ⬍1,000,000 and ⱖ 3,000,000 won 1,000,000–1,999,999 won 2,000,000–2,999,999 won ⱕ3,000,000 won Missing Type of surgery Modified radical mastectomy Partial mastectomy Stage of disease Stage I Stage II Stage III
n
Percent
1 36 61 25 11
0.8 27.3 46.1 19.1 7.7
3 113 3 9 4 2
2.2 84.3 2.2 6.7 3.0 1.5
16 24 65 24 5
11.9 17.9 48.5 17.9 3.7
50 34 16 31 3
37.3 25.4 11.9 23.1 2.2
30 49 27 21 7
22.4 36.6 20.1 15.7 5.2
93 41
69.4 30.6
26 96 12
19.4 71.7 9.0
a
The approximate exchange rate is 1,200 South Korean won to US$ 1.
independently by two bilingual translators who were aware of the intent and concepts underlying the instrument. The two preliminarily translated Korean versions of the SES and were reviewed by one of the researchers in this study, and these Korean versions of the SES were sent to two bilinguals to translate it back to English. Two bilingual individuals who are experts in the intent of the measures and the concepts compared the original and back-translated versions to validate the translations. Based upon the results from the comparison, the two versions were combined into a final Korean version of the SES. The SES consists of eight common symptoms associated with treatment for breast cancer: nausea, pain, appetite, sleep, fatigue,
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bowel pattern, concentration, and appearance. Each symptom is measured for its frequency, intensity, and associated distress; thus, the SES consists of a total of 24 items. The items are measured on a 5-point Likert-type scale, which contains descriptions of the frequency, intensity, and distress of symptoms. Cronbach’s alpha of the SES was reported as 0.94 and the initial construct validity was established. In this study, Cronbach’s alpha was 0.93. A total score (range 0–96) is obtained by summing all the item scores, with higher scores indicating a more negative symptom experience. Mood disturbance was measured using the Linear Analogue Self-Assessment Scale,32,33 which consists of six 10-mm linear analogue scales for quantifying the following aspects of mood: anxiety, confusion, depression, fatigue, anger, and energy. Tests of concurrent validity with the Profile of Mood Status yielded Spearman rank correlation coefficients of 0.79–0.83. Cronbach’s alpha in a longitudinal study with six time points involving 121 women with breast cancer ranged from 0.74 to 0.87.34 In the present study, Cronbach’s alpha was 0.85. A total score is obtained by summing the scores for the six items, with the score of energy weighted negatively. In the present study, the item measuring fatigue was not included in the scoring because there was a conceptual overlap between this item and items in the SES.29 A higher score indicates a higher level of mood disturbance. Social support was measured using the Social Support Scale (SSS),27 which consists of family support (eight items) and professional health team support (eight items) scales scored using a 5-point Likert-type scale, where a score of 1 indicates “not at all” and a score of 5 indicates “always.” Content validity of the SSS was established by a panel of three experts on social support. Cronbach’s alpha of family support and professional health team support were reported as 0.82 and 0.84, respectively, in 247 Korean patients with cancer. In another study with Korean patients with breast cancer,26 Cronbach’s alpha of the SSS was 0.88. In the present study, Cronbach’s alpha was 0.94. A total score was obtained by averaging all item scores, and a higher score indicates a higher level of social support.
Data Collection Procedures After approval of an institutional review board from each medical center located in the
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cities of Suwon and Daegu in South Korea, participants were recruited from outpatient clinics of the medical centers. Potential participants were identified by the physicians or nurses providing care. Those who meet the inclusion criteria and were interested in participating were asked to contact a researcher or research assistant. Those who wished to participate were met in a waiting room or a small private room while waiting to be seen by the physician or while waiting for the administration of chemotherapy. During the contact, the purpose of the study and the nature of participation were outlined. If a patient articulated an understanding of the study and agreed to participate, the patient signed a consent form and was given a packet containing questionnaires and a stamped, selfaddressed return envelope. The questionnaires were completed at home, and the were returned in the stamped, self-addressed envelope. A followup letter emphasizing the importance of participating in the study was sent four days after each questionnaire had been handed out. A total of 176 patients agreed to participate and signed an informed consent form. Of those, 134 questionnaires were returned. The response rate of the questionnaires was 76.14%.
Data Analysis The Statistical Package for the Social Sciences (SPSS for Windows, version 10) was used to analyze the data. Descriptive statistics were computed for the study variables. The following aspects of the data were also assessed using regression analysis: homocedasticity, normality, linearity, no multivariate outliers of residuals, and multicollinearity.35 However, neither case deletion nor data transformation was required. Hypotheses 1–3 were tested using Pearson correlation analyses. Hypothesis 4 was tested using hierarchical multiple regression, since the predictor variables (mood disturbance and social support) were continuous.36,37
Results Descriptive statistics of the main study variables are presented in Table 2. The mean scores of the symptom experience and mood disturbance were 32.44 (SD ⫽ 14.91) and 108.06 (SD ⫽ 89.51), respectively, indicating that the majority of the sample experienced low-to-moderate levels of symptom and mood disturbance.
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Table 2 Results of Symptom Experience, Mood Disturbance, and Social Support Variable/Subdomain or Subitems Symptom experience Nausea Pain Appetite Sleep Fatigue Bowel pattern Concentration Appearance Mood disturbance Anxiety Confusion Depression Fatigue Anger Energy Social support Family Health Professional
M
SD
Possible Range
Actual Range
Skewness/SE Skewness
32.44 4.68 4.01 4.34 3.60 4.92 3.98 3.10 3.81 108.06a 40.47 34.12 39.23 44.66 35.62 41.43b 3.71 4.07 3.67
14.91 2.71 2.47 3.44 2.91 2.26 3.12 2.30 2.70 89.51 25.98 24.67 27.05 24.59 27.04 23.66 .99 .94 1.30
0–96 0–12 0–12 0–12 0–12 0–12 0–12 0–12 0–12 ⫺100.00 to 400.00 0–100 0–100 0–100 0–100 0–100 0–100 1–5 1–5 1–5
0–68 0–11 0–12 0–12 0–12 0–12 0–12 0–9 0–12 ⫺71.00 to 312.00 2–92 1–88 2–92 2–94 0–93 2–99 1.25–5.00 1.38–5.00 1.00–5.00
0.92
0.17
⫺1.91
SE skew ⫽ standard error of skewness. a The score of fatigue was not included in the total score because of conceptual overlap with symptom experience. b Energy was negatively weighted when scoring the mood disturbance.
However, most of the sample perceived a moderately high level of social support (M ⫽ 3.71, SD ⫽ 0.99) with a possible range of 1 to 5. There was little skewness in the distributions of symptom experience, mood disturbance, and social support, meaning that they were relatively symmetrical in distribution. The first hypothesis of the relationship of mood disturbance to symptom experience was statistically significant (r ⫽ 0.43, P ⫽ 0.00), indicating the first hypothesis was supported. However, social support was not correlated with symptom experience, and hence the second hypothesis was not supported. Regarding the third hypothesis, there was a significant negative but low correlation between social support and mood disturbance (r ⫽ ⫺0.25, P ⫽ 0.004). To test the fourth hypothesis, a hierarchical multiple regression analysis was performed. A cross-product term was calculated by multiplying the scores of mood disturbance by social support. Mood disturbance and social support were entered simultaneously in the regression equation, and the cross-product term of mood disturbance and social support was entered later in the regression equation. In the hierarchical multiple regression process, the direction of the β term of mood disturbance shifted from positive (0.464) to negative (⫺0.437) when the cross-product term was entered into the multiple regression equation consisting of
mood disturbance and social support. This might have been due to multicollinearity between predictor variables (mood disturbance in this study) and the cross-product term, resulting in “bouncing betas” when the uncentered variables were multiplied to form a cross-product term.38,39 To solve this problem, the predictor variables (mood disturbance and social support) were centered by subtracting the respective means from each of the variables.40 After centering, the multicollinearity between mood disturbance and cross-product term decreased from r ⫽ 0.92 to r ⫽ 0.21. Table 3 displays R, overall F, R2, and F change from the hierarchical multiple regression analysis. At Step 2, the value of R was statistically significant [F(3,130) ⫽ 16.24, P ⫽ 0.000]. Mood disturbance, social support, and the crossproduct term together significantly accounted for 27% of the variance in symptom experience. The R2 change for the cross-product form was 0.05 (P ⫽ 0.005). Thus, the fourth hypothesis was supported. Statistically significant interactions are interpreted by simple regression equations for high, average, and low values of a moderator variable.38,41 The simple regression equations were derived using a multiple regression equation including the terms for two main effects (centered mood disturbance and social support) and the cross-product term (centered
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Table 3 Hierarchical Multiple Regression of Mood Disturbance, Social Support, and Cross-Product Term on Symptom Experience Step
Overall F
R
R2
F change
B a
1. Mood disturbance Social support 2. Cross-product term Constant
0.52 0.50
F (2, 131) ⫽ 18.71a F (3, 130) ⫽ 16.24a
0.22 0.27
18.71a 9.01a
0.018 0.445 0.010a 8.098
SE
b
0.003 0.282 0.003 0.278
0.44 0.12 0.23
P ⬍ 0.01.
a
mood disturbance ⫻ centered social support), along with the corresponding unstandardized regression coefficients (b) and a constant (Table 3). From the multiple regression, simple regression equations for mood disturbance were computed at plus one standard deviation, at the mean, and at minus one standard deviation for high, average, and low levels of social support.37,42 Table 4 displays the unstandardized simple regression coefficients for mood disturbance on symptom experience at low, average, and high levels of social support. To identify whether or not the simple regression coefficients were statistically different from zero, the coefficients were divided by their associated standard error (for a more detailed calculation of standard error refer to Aiken and West40) using a Bonferroni procedure38 at an alpha level of 0.01. The coefficients at the low and average levels of social support were statistically different from zero. When mood disturbance increased by one unit, symptom experience increased by 0.028 units at low levels of social support and by 0.018 units at average levels of social support. However, the coefficient did not differ statistically from zero when social support was high, indicating that there was no relationship between mood disturbance and symptom experience when the level of social support was high.
Discussion The present study identified how mood disturbance and social support were related to Table 4 Unstandardized Regression Coefficients for Mood Disturbance on Symptom Experience at Low, Average, and High Levels of Social Support Social Support Low Average High P ⬍ 0.001
a
b
SE
0.028 0.018 0.008
0.004 0.003 0.005
t 7.0a 6.0a 1.6
symptom experience of Korean women undergoing chemotherapy for breast cancer based upon a middle-range TOUS and a literature review on breast cancer. In the present study, 46.1% of the participants were 40–49 years old, which is consistent with the National Statistical Report that the highest proportion of Korean patients diagnosed with breast cancer (39.4%) are in this age group.1 The score of total symptom experience in this study was twice the score of 17.93 in a study of 252 American women by Samarel et al.29 This difference may be attributable to all the participants in the present study receiving chemotherapy, whereas only 43% of the women were receiving treatments in the American study. The highest score in the subdomains of symptom experience was for fatigue, which is consistent with the studies by Hur and colleagues43 involving 301 Korean cancer patients, and that by Berger.44 The women in the present study experienced a low-to-moderate level of mood disturbance. This was consistent with the study by Irvine et al.34 involving women receiving radiation therapy for breast cancer. In this study, the overall mean score for social support was 3.71 (on a scale of 1–5), indicating that the majority of the participants received a moderately high level of social support. In particular, the mean score for the domain of family support from spouse, parents, siblings, sisters, children, or other extended family was 4.07 (SD ⫽ 0.94), which is similar with a previous study of Korean women undergoing chemotherapy for breast cancer.26 It can be conjectured that women receive a high level of family support but a relatively low level of professional support while undergoing chemotherapy for breast cancer. Consistent with previous studies,17,18 mood disturbance was positively correlated with the symptoms experienced by women in this study.
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However, the strength of the relationship was moderated by social support. Mood disturbance was positively influenced by the symptom experience of women who perceived an average and low level of social support, but it was not influenced in women receiving a high level of social support. In other words, a higher level of mood disturbance led to a higher level of symptoms when they received average or low levels of social support. These findings are both theoretically and clinically important. One of the roles of a theory—particularly a middle-range theory—is to guide practice; hence health professionals have been placing more emphasis on using theory for knowledgebased practice. However, testing whether or not a theory is pragmatic is required before implementing it in a particular population. Even though the TOUS is thought to be pragmatic in the care of cancer patients,45 it has not actually been tested with this population.46 The present study is the first to test the TOUS with cancer patients, and it provides support for the proposition that psychological and situational factors interact with symptom experience. One of the most important contributions of this study is quantifying the applicability of parts of the TOUS to cancer patients in practice. Lewis and Kliewer47 noted that testing a potential interaction effect is clinically important because an interaction effect leads to the identification of subgroups that are more resilient or vulnerable under certain conditions. From the testing of an interaction effect in this study, it was found that women with a higher level of mood disturbance were at higher risk of experiencing symptoms when the level of social support was average or low. This finding indicates that clinical professionals in practice must consider the levels of social support when applying interventions to decrease the impact of mood disturbance on symptoms for women undergoing chemotherapy for breast cancer. In addition, the present study revealed a low and negative relationship between social support and mood disturbance, which is consistent with previous studies involving breast cancer patients.26,27 However, studies involving patients with testicular,48 lung,49 and head and neck50 cancer have revealed no relationship between social support and psychologic problems, such as mood disturbance or depression. The discrepancy indicates the need to investigate
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further if the relationship between social support and mood disturbance depends on the type of cancer. The findings of this study should be interpreted cautiously due to the presence of some limitations. First, internal validity may be an issue due to the use of instrument developed for American cancer patients in English. Even though the validity and reliability of the SES has been established with American cancer patients, it has never been tested with Korean cancer patients. In this study, the SES was translated into Korean and then back-translated to verify the translation. Internal consistency reliability of the SES in this study was established by a Cronbach’s alpha of 0.93. However, the validity of the SES was not tested with Korean cancer patients—this requires further investigation. Second, the findings were based upon cross-sectional and correctional data, not allowing for inference of causality. The predictive power of mood disturbance and social support would be strengthened through the use of a longitudinal design. In summary, this study shows that the impact of mood disturbance on symptom experience depends on the level of social support. This suggests that clinical interventions for attenuating the impact of mood disturbance on symptom experience might be effective only in women receiving average or low levels of social support.
Acknowledgments The authors would like to thank the patients who willingly participated in this study. The authors also acknowledge the ONS/Ortho Biotech Inc. for financial support. Finally, the authors wish to thank M. Bok, RN, and J.-H. Lee, RN, for their help with the collection of data and H.-J. Lee for their assistance in the preparation of the manuscript.
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44. Berger AM. Patterns of fatigue, activity and rest during adjuvant breast cancer chemotherapy. Oncol Nurs Forum 1998;25:51–62. 45. Lenz ER, Gift AG. Response to the theory of unpleasant symptoms and Alzheimer’s disease. Image 1998;12:159–162. 46. Lee E. Evaluation and analysis of the Theory of Unpleasant Symptoms. J Korean Acad Nurs 2000;30: 1627–1635. 47. Lewis H, Kliewer W. Hope, coping and adjustment among child with sickle cell disease: testing of mediator and moderator model. J Ped Psychol 1996; 21:25–41. 48. Ord-Lawson S, Fitch M. The relationship between perceived social support and mood of testicular cancer patients. Can Oncol Nurs J 1997;7(2):90–95. 49. Uchitomi Y, Mikami I, Kugaya A, et al. Physician support and patient psychologic responses after surgery for nonsmall cell lung carcinoma: a prospective observational study. Cancer 2001;92(7):1926–1935. 50. Kugaya A, Akechi T, Okamura H, et al. Correlates of depressed mood in ambulatory head and neck cancer patients. PsychoOncology 1999;8(6):494–499.
Journal of Pain and Symptom Management
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Original Article
Relationships of Mood Disturbance and Social Support to Symptom Experience in Korean Women with Breast Cancer Eun-Hyun Lee, PhD, RN, Bok Yae Chung, PhD, RN, Hee Boog Park, PhD, MD, and Ki Hong Chun, PhD, MD School of Medicine, Ajou University (E.-H.L., H.B.P., K.H.C.), Suwon; and Division of Nursing (B.Y.C.), Kyungpook National University, Taegu, South Korea
Abstract The purpose of this study was to identify how mood disturbance and social support were related to the symptoms experienced by Korean women with breast cancer. A cross-sectional, correlational design was used for the study. A convenience sample of 134 Korean women receiving chemotherapy for breast cancer was recruited. The participants completed questionnaires on symptom experience using the Symptom Experience Scale, mood disturbance using the Linear Analogue Self-Assessment Scale, and social support using the Social Support Scale. Mood disturbance and social support had a significant interaction effect on symptom experience. A higher level of mood disturbance led to a higher level of symptoms when the level of social support was average or low, which implies that clinical interventions for attenuating the impact of mood disturbance on symptom experience might be effective only for women perceiving average or low levels of social support. J Pain Symptom Manage 2004;27:425–433. 쑖 2004 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Breast cancer, symptom experience, mood disturbance, social support, interaction effect
Introduction In the past, the low prevalence of breast cancer in Asia led to the condition being considered a ‘Western affliction.’ However, in recent times, the number of Korean women diagnosed with breast cancer has increased rapidly. According to the Korean Ministry of Health and Welfare,1 breast cancer is now the most common type of cancer in Korean women.
Address reprint requests to: Eun-Hyun Lee, PhD, RN, Ajou University School of Medicine, San 5, WonchonDong, Paldal-Gu, Suwon 442-721, South Korea. Accepted for publication: October 6, 2003.
쑖 2004 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved.
The primary treatment for breast cancer involves surgery. Based upon surgical findings and pathology, adjuvant treatment such as radiation therapy or chemotherapy is given.2 In many breast cancer patients, adjuvant chemotherapy has side effects of multiple symptoms which interfere with daily activities,3 social independence,4 self-care,5 adjustment,6 and quality of life.7 Considering their negative impact, symptoms are a major focus in the care of patients with breast cancer. In their theory of unpleasant symptoms (TOUS), Lenz et al.8 characterized symptoms as the perceived indicators of change in normal functioning, as experienced by patients. Symptoms can occur alone or in isolation from each 0885-3924/04/$–see front matter doi:10.1016/j.jpainsymman.2003.10.007
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other, but in many cases multiple symptoms are experienced simultaneously. Symptoms are also characterized as consisting of common shared dimensions—such as frequency, intensity, and distress—across symptoms that are not limited to one symptom. Women with breast cancer, especially those undergoing adjuvant therapy, experience multiple adverse symptoms such as nausea, vomiting, fatigue, anorexia, and hair loss.9 Some investigators have reported that nausea and vomiting can occur more than 24 hours after chemotherapy in 60–80% of patients.10,11 Portenoy et al. reported that the most frequently experienced symptoms in 297 patients with cancer (of whom 32% had breast cancer) were lack of energy, lack of appetite, and pain.12 In a one-year longitudinal study of 93 breast cancer patients, Hoskins, Budin, and Maislin13 found that fatigue was a common experience that prevailed throughout the recovery period from 30 days to 6 months postsurgery, but was relieved after one year. Nausea, vomiting, and hair loss were also present from approximately 30 days to 6 months. Meyerowitz, Watkins, and Sparks14 interviewed 50 women during treatment with adjuvant chemotherapy for breast cancer, and reported fatigue, nausea, and irritability as the most distressing symptoms. Hair loss is also reported as one of the most upsetting experiences for women undergoing chemotherapy for breast cancer.2 It is, therefore, clear that women with breast cancer experience multiple unpleasant symptoms related to chemotherapy. The TOUS8 noted that psychological and situational factors directly influence the symptoms that patients experience. Psychological factors refer to mood, the affective reaction to illness, and the degree of uncertainty and knowledge about the symptoms and their meaning. Various psychological issues are associated with breast cancer and its treatment, of which mood disturbance (such as anxiety and depression) has been noted as a serious psychological problem. Some investigators have stated that many women with breast cancer experience mild to severe forms of anxiety, depression, hostility, sadness, frustration, and anger as responses to the disease and its treatment.15,16 In the study by Cimprich17 on women newly diagnosed with breast cancer, mood disturbance was significantly correlated with the number of
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symptoms experienced (r ⫽ 0.65, P ⬍ 0.01). In a similar vein, Piper demonstrated that the intensity and frequency of fatigue was moderately correlated with mood disturbance in women with breast cancer.18 Situational factors in the TOUS8 refer to aspects of the social environment, such as social support, and of the physical environment, such as noise and light. In women with breast cancer, social support has emerged as an important situational resource that can relieve symptoms,7 because patients tend to feel better when social support is available.19,20 Social support has been broadly defined as the resources provided by others.21 The term social support is often specified by its source components, such as kinship, the professional network, and the community.22,23 In their qualitative studies, Jun24 and Chung25 noted that family members are pivotal in supporting Korean women with breast cancer, and healthcare professionals are also an important source of support, especially during the period of adjuvant treatment for breast cancer. In the study by Budin6 involving 101 unmarried women with breast cancer, perceived social support was related to symptom distress (r ⫽ ⫺0.22, P ⬍ 0.01), which is a dimension of symptom experience. Lenz et al. also asserted that the psychological and situational factors in the TOUS8 are related to each other, and that these factors interact in their correlation with symptom experience. In 93 Korean women undergoing chemotherapy for breast cancer, it was found that family support was negatively related with anxiety (r ⫽ ⫺0.23, P ⬍ 0.05).26 Similarly, in a study on Korean patients receiving chemotherapy or radiation therapy, Tae27 reported that perceived professional medical support was significantly and negatively related to depression (r ⫽ ⫺0.15, P ⬍ 0.001). Although a negative relationship between social support and mood disturbance in women with breast cancer has been reported, the interaction effect of social support and mood disturbance on symptom experience has never been tested. Based upon the TOUS and a literature review on breast cancer, the purpose of this study was to identify the relationships of mood disturbance and social support on the symptom experience of women undergoing chemotherapy for breast cancer. The specific hypotheses were as follows: 1) there will be a direct relationship of
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mood disturbance to symptom experience; 2) there will be a direct relationship of social support to symptom experience; 3) there will be a negative relationship between social support and mood disturbance; and 4) there will be an interaction effect of mood disturbance and social support on symptom experience.
Methods Design and Sample A cross-sectional, correlational design was used to examine the relationships of mood distribution and social support to symptom experience in Korean women with breast cancer. The convenience sample used in this study comprised 134 women with a diagnosis of breast cancer who were undergoing adjuvant chemotherapy, prescribed antiemetic medicine, over 18 years of age, and literate in Korean. Based upon the guideline by Cohen,28 the sample size met the requirement for a Pearson’s correlation analysis to detect a medium effect size (r ⫽ 0.30) at an alpha of 0.05 with a statistical power of 0.8, and for a multiple regression analysis with two predictors and one cross-product term (mood disturbance ⫻ social support) to detect a medium effect size (f 2 ⫽ 0.15) at an alpha of 0.05 with a statistical power of 0.8. Table 1 presents the general characteristics and medical information of the sample population. The age ranged from 26 years to 69 years, with a mean of 45.29 years (SD ⫽ 8.75). Most of the subjects were married (84.3%), had at least a high school degree (66.4%), and were predominantly Buddhist (37.3%) or Protestant (25.4%). The monthly income of 49 of the women (36.6%) was 1,000,000–1,999,999 South Korean won (US$ 830–1,670). Ninety-three women (69.4%) had received a modified radical mastectomy, and approximately two-thirds of the sample had Stage II breast cancer.
Instruments Symptom experience was measured using the Symptom Experience Scale (SES).29 The SES has never been applied to a Korean population, and thus it was translated into Korean using a back-translation technique which is the most common and highly recommended procedure for translating such an instrument.30,31 The SES was first translated from English into Korean
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Table 1 General Characteristics and Medical Information (n ⫽ 134) Variable Age (years) 26–29 30–39 40–49 50–59 60–69 Marital status Single, never married Married Divorced Widow Separated Missing Education completed Elementary school Middle school High school Baccalaureate degree and over Missing Religion Buddhist Protestant Roman Catholic None Missing Monthly incomea ⬍1,000,000 and ⱖ 3,000,000 won 1,000,000–1,999,999 won 2,000,000–2,999,999 won ⱕ3,000,000 won Missing Type of surgery Modified radical mastectomy Partial mastectomy Stage of disease Stage I Stage II Stage III
n
Percent
1 36 61 25 11
0.8 27.3 46.1 19.1 7.7
3 113 3 9 4 2
2.2 84.3 2.2 6.7 3.0 1.5
16 24 65 24 5
11.9 17.9 48.5 17.9 3.7
50 34 16 31 3
37.3 25.4 11.9 23.1 2.2
30 49 27 21 7
22.4 36.6 20.1 15.7 5.2
93 41
69.4 30.6
26 96 12
19.4 71.7 9.0
a
The approximate exchange rate is 1,200 South Korean won to US$ 1.
independently by two bilingual translators who were aware of the intent and concepts underlying the instrument. The two preliminarily translated Korean versions of the SES and were reviewed by one of the researchers in this study, and these Korean versions of the SES were sent to two bilinguals to translate it back to English. Two bilingual individuals who are experts in the intent of the measures and the concepts compared the original and back-translated versions to validate the translations. Based upon the results from the comparison, the two versions were combined into a final Korean version of the SES. The SES consists of eight common symptoms associated with treatment for breast cancer: nausea, pain, appetite, sleep, fatigue,
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bowel pattern, concentration, and appearance. Each symptom is measured for its frequency, intensity, and associated distress; thus, the SES consists of a total of 24 items. The items are measured on a 5-point Likert-type scale, which contains descriptions of the frequency, intensity, and distress of symptoms. Cronbach’s alpha of the SES was reported as 0.94 and the initial construct validity was established. In this study, Cronbach’s alpha was 0.93. A total score (range 0–96) is obtained by summing all the item scores, with higher scores indicating a more negative symptom experience. Mood disturbance was measured using the Linear Analogue Self-Assessment Scale,32,33 which consists of six 10-mm linear analogue scales for quantifying the following aspects of mood: anxiety, confusion, depression, fatigue, anger, and energy. Tests of concurrent validity with the Profile of Mood Status yielded Spearman rank correlation coefficients of 0.79–0.83. Cronbach’s alpha in a longitudinal study with six time points involving 121 women with breast cancer ranged from 0.74 to 0.87.34 In the present study, Cronbach’s alpha was 0.85. A total score is obtained by summing the scores for the six items, with the score of energy weighted negatively. In the present study, the item measuring fatigue was not included in the scoring because there was a conceptual overlap between this item and items in the SES.29 A higher score indicates a higher level of mood disturbance. Social support was measured using the Social Support Scale (SSS),27 which consists of family support (eight items) and professional health team support (eight items) scales scored using a 5-point Likert-type scale, where a score of 1 indicates “not at all” and a score of 5 indicates “always.” Content validity of the SSS was established by a panel of three experts on social support. Cronbach’s alpha of family support and professional health team support were reported as 0.82 and 0.84, respectively, in 247 Korean patients with cancer. In another study with Korean patients with breast cancer,26 Cronbach’s alpha of the SSS was 0.88. In the present study, Cronbach’s alpha was 0.94. A total score was obtained by averaging all item scores, and a higher score indicates a higher level of social support.
Data Collection Procedures After approval of an institutional review board from each medical center located in the
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cities of Suwon and Daegu in South Korea, participants were recruited from outpatient clinics of the medical centers. Potential participants were identified by the physicians or nurses providing care. Those who meet the inclusion criteria and were interested in participating were asked to contact a researcher or research assistant. Those who wished to participate were met in a waiting room or a small private room while waiting to be seen by the physician or while waiting for the administration of chemotherapy. During the contact, the purpose of the study and the nature of participation were outlined. If a patient articulated an understanding of the study and agreed to participate, the patient signed a consent form and was given a packet containing questionnaires and a stamped, selfaddressed return envelope. The questionnaires were completed at home, and the were returned in the stamped, self-addressed envelope. A followup letter emphasizing the importance of participating in the study was sent four days after each questionnaire had been handed out. A total of 176 patients agreed to participate and signed an informed consent form. Of those, 134 questionnaires were returned. The response rate of the questionnaires was 76.14%.
Data Analysis The Statistical Package for the Social Sciences (SPSS for Windows, version 10) was used to analyze the data. Descriptive statistics were computed for the study variables. The following aspects of the data were also assessed using regression analysis: homocedasticity, normality, linearity, no multivariate outliers of residuals, and multicollinearity.35 However, neither case deletion nor data transformation was required. Hypotheses 1–3 were tested using Pearson correlation analyses. Hypothesis 4 was tested using hierarchical multiple regression, since the predictor variables (mood disturbance and social support) were continuous.36,37
Results Descriptive statistics of the main study variables are presented in Table 2. The mean scores of the symptom experience and mood disturbance were 32.44 (SD ⫽ 14.91) and 108.06 (SD ⫽ 89.51), respectively, indicating that the majority of the sample experienced low-to-moderate levels of symptom and mood disturbance.
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Table 2 Results of Symptom Experience, Mood Disturbance, and Social Support Variable/Subdomain or Subitems Symptom experience Nausea Pain Appetite Sleep Fatigue Bowel pattern Concentration Appearance Mood disturbance Anxiety Confusion Depression Fatigue Anger Energy Social support Family Health Professional
M
SD
Possible Range
Actual Range
Skewness/SE Skewness
32.44 4.68 4.01 4.34 3.60 4.92 3.98 3.10 3.81 108.06a 40.47 34.12 39.23 44.66 35.62 41.43b 3.71 4.07 3.67
14.91 2.71 2.47 3.44 2.91 2.26 3.12 2.30 2.70 89.51 25.98 24.67 27.05 24.59 27.04 23.66 .99 .94 1.30
0–96 0–12 0–12 0–12 0–12 0–12 0–12 0–12 0–12 ⫺100.00 to 400.00 0–100 0–100 0–100 0–100 0–100 0–100 1–5 1–5 1–5
0–68 0–11 0–12 0–12 0–12 0–12 0–12 0–9 0–12 ⫺71.00 to 312.00 2–92 1–88 2–92 2–94 0–93 2–99 1.25–5.00 1.38–5.00 1.00–5.00
0.92
0.17
⫺1.91
SE skew ⫽ standard error of skewness. a The score of fatigue was not included in the total score because of conceptual overlap with symptom experience. b Energy was negatively weighted when scoring the mood disturbance.
However, most of the sample perceived a moderately high level of social support (M ⫽ 3.71, SD ⫽ 0.99) with a possible range of 1 to 5. There was little skewness in the distributions of symptom experience, mood disturbance, and social support, meaning that they were relatively symmetrical in distribution. The first hypothesis of the relationship of mood disturbance to symptom experience was statistically significant (r ⫽ 0.43, P ⫽ 0.00), indicating the first hypothesis was supported. However, social support was not correlated with symptom experience, and hence the second hypothesis was not supported. Regarding the third hypothesis, there was a significant negative but low correlation between social support and mood disturbance (r ⫽ ⫺0.25, P ⫽ 0.004). To test the fourth hypothesis, a hierarchical multiple regression analysis was performed. A cross-product term was calculated by multiplying the scores of mood disturbance by social support. Mood disturbance and social support were entered simultaneously in the regression equation, and the cross-product term of mood disturbance and social support was entered later in the regression equation. In the hierarchical multiple regression process, the direction of the β term of mood disturbance shifted from positive (0.464) to negative (⫺0.437) when the cross-product term was entered into the multiple regression equation consisting of
mood disturbance and social support. This might have been due to multicollinearity between predictor variables (mood disturbance in this study) and the cross-product term, resulting in “bouncing betas” when the uncentered variables were multiplied to form a cross-product term.38,39 To solve this problem, the predictor variables (mood disturbance and social support) were centered by subtracting the respective means from each of the variables.40 After centering, the multicollinearity between mood disturbance and cross-product term decreased from r ⫽ 0.92 to r ⫽ 0.21. Table 3 displays R, overall F, R2, and F change from the hierarchical multiple regression analysis. At Step 2, the value of R was statistically significant [F(3,130) ⫽ 16.24, P ⫽ 0.000]. Mood disturbance, social support, and the crossproduct term together significantly accounted for 27% of the variance in symptom experience. The R2 change for the cross-product form was 0.05 (P ⫽ 0.005). Thus, the fourth hypothesis was supported. Statistically significant interactions are interpreted by simple regression equations for high, average, and low values of a moderator variable.38,41 The simple regression equations were derived using a multiple regression equation including the terms for two main effects (centered mood disturbance and social support) and the cross-product term (centered
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Table 3 Hierarchical Multiple Regression of Mood Disturbance, Social Support, and Cross-Product Term on Symptom Experience Step
Overall F
R
R2
F change
B a
1. Mood disturbance Social support 2. Cross-product term Constant
0.52 0.50
F (2, 131) ⫽ 18.71a F (3, 130) ⫽ 16.24a
0.22 0.27
18.71a 9.01a
0.018 0.445 0.010a 8.098
SE
b
0.003 0.282 0.003 0.278
0.44 0.12 0.23
P ⬍ 0.01.
a
mood disturbance ⫻ centered social support), along with the corresponding unstandardized regression coefficients (b) and a constant (Table 3). From the multiple regression, simple regression equations for mood disturbance were computed at plus one standard deviation, at the mean, and at minus one standard deviation for high, average, and low levels of social support.37,42 Table 4 displays the unstandardized simple regression coefficients for mood disturbance on symptom experience at low, average, and high levels of social support. To identify whether or not the simple regression coefficients were statistically different from zero, the coefficients were divided by their associated standard error (for a more detailed calculation of standard error refer to Aiken and West40) using a Bonferroni procedure38 at an alpha level of 0.01. The coefficients at the low and average levels of social support were statistically different from zero. When mood disturbance increased by one unit, symptom experience increased by 0.028 units at low levels of social support and by 0.018 units at average levels of social support. However, the coefficient did not differ statistically from zero when social support was high, indicating that there was no relationship between mood disturbance and symptom experience when the level of social support was high.
Discussion The present study identified how mood disturbance and social support were related to Table 4 Unstandardized Regression Coefficients for Mood Disturbance on Symptom Experience at Low, Average, and High Levels of Social Support Social Support Low Average High P ⬍ 0.001
a
b
SE
0.028 0.018 0.008
0.004 0.003 0.005
t 7.0a 6.0a 1.6
symptom experience of Korean women undergoing chemotherapy for breast cancer based upon a middle-range TOUS and a literature review on breast cancer. In the present study, 46.1% of the participants were 40–49 years old, which is consistent with the National Statistical Report that the highest proportion of Korean patients diagnosed with breast cancer (39.4%) are in this age group.1 The score of total symptom experience in this study was twice the score of 17.93 in a study of 252 American women by Samarel et al.29 This difference may be attributable to all the participants in the present study receiving chemotherapy, whereas only 43% of the women were receiving treatments in the American study. The highest score in the subdomains of symptom experience was for fatigue, which is consistent with the studies by Hur and colleagues43 involving 301 Korean cancer patients, and that by Berger.44 The women in the present study experienced a low-to-moderate level of mood disturbance. This was consistent with the study by Irvine et al.34 involving women receiving radiation therapy for breast cancer. In this study, the overall mean score for social support was 3.71 (on a scale of 1–5), indicating that the majority of the participants received a moderately high level of social support. In particular, the mean score for the domain of family support from spouse, parents, siblings, sisters, children, or other extended family was 4.07 (SD ⫽ 0.94), which is similar with a previous study of Korean women undergoing chemotherapy for breast cancer.26 It can be conjectured that women receive a high level of family support but a relatively low level of professional support while undergoing chemotherapy for breast cancer. Consistent with previous studies,17,18 mood disturbance was positively correlated with the symptoms experienced by women in this study.
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However, the strength of the relationship was moderated by social support. Mood disturbance was positively influenced by the symptom experience of women who perceived an average and low level of social support, but it was not influenced in women receiving a high level of social support. In other words, a higher level of mood disturbance led to a higher level of symptoms when they received average or low levels of social support. These findings are both theoretically and clinically important. One of the roles of a theory—particularly a middle-range theory—is to guide practice; hence health professionals have been placing more emphasis on using theory for knowledgebased practice. However, testing whether or not a theory is pragmatic is required before implementing it in a particular population. Even though the TOUS is thought to be pragmatic in the care of cancer patients,45 it has not actually been tested with this population.46 The present study is the first to test the TOUS with cancer patients, and it provides support for the proposition that psychological and situational factors interact with symptom experience. One of the most important contributions of this study is quantifying the applicability of parts of the TOUS to cancer patients in practice. Lewis and Kliewer47 noted that testing a potential interaction effect is clinically important because an interaction effect leads to the identification of subgroups that are more resilient or vulnerable under certain conditions. From the testing of an interaction effect in this study, it was found that women with a higher level of mood disturbance were at higher risk of experiencing symptoms when the level of social support was average or low. This finding indicates that clinical professionals in practice must consider the levels of social support when applying interventions to decrease the impact of mood disturbance on symptoms for women undergoing chemotherapy for breast cancer. In addition, the present study revealed a low and negative relationship between social support and mood disturbance, which is consistent with previous studies involving breast cancer patients.26,27 However, studies involving patients with testicular,48 lung,49 and head and neck50 cancer have revealed no relationship between social support and psychologic problems, such as mood disturbance or depression. The discrepancy indicates the need to investigate
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further if the relationship between social support and mood disturbance depends on the type of cancer. The findings of this study should be interpreted cautiously due to the presence of some limitations. First, internal validity may be an issue due to the use of instrument developed for American cancer patients in English. Even though the validity and reliability of the SES has been established with American cancer patients, it has never been tested with Korean cancer patients. In this study, the SES was translated into Korean and then back-translated to verify the translation. Internal consistency reliability of the SES in this study was established by a Cronbach’s alpha of 0.93. However, the validity of the SES was not tested with Korean cancer patients—this requires further investigation. Second, the findings were based upon cross-sectional and correctional data, not allowing for inference of causality. The predictive power of mood disturbance and social support would be strengthened through the use of a longitudinal design. In summary, this study shows that the impact of mood disturbance on symptom experience depends on the level of social support. This suggests that clinical interventions for attenuating the impact of mood disturbance on symptom experience might be effective only in women receiving average or low levels of social support.
Acknowledgments The authors would like to thank the patients who willingly participated in this study. The authors also acknowledge the ONS/Ortho Biotech Inc. for financial support. Finally, the authors wish to thank M. Bok, RN, and J.-H. Lee, RN, for their help with the collection of data and H.-J. Lee for their assistance in the preparation of the manuscript.
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Symptom Experience of Koreans with Breast Cancer
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