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© 2000 American Society for Clinical Oncology Fatigue in Breast Cancer Survivors: Occurrence, Correlates, and Impact on Quality of LifeFrom the Norman Cousins Center in Psychoneuroimmunology, Departments of Biostatistics and Psychiatry and Biobehavioral Sciences, Schools of Public Health and Medicine, Division of Cancer Prevention and Control Research, Jonsson Comprehensive Cancer Center, University of California, Los Angeles; Department of Psychology, University of Southern California, Los Angeles, CA; and Department of Psychiatry, Georgetown University Medical School and Lombardi Cancer Center, Washington, DC. Address reprint requests to Patricia A. Ganz, MD, Division of Cancer Prevention and Control Research, Jonsson Comprehensive Cancer Center, 650 Charles Young Dr South, Room A2-125, CHS Box 956900, Los Angeles, CA 90095-6900; email pganz{at}ucla.edu
PURPOSE: To describe the occurrence of fatigue in a large sample of breast cancer survivors relative to general population norms and to identify demographic, medical, and psychosocial characteristics of fatigued survivors. PATIENTS AND METHODS: Breast cancer survivors in two large metropolitan areas completed standardized questionnaires as part of a survey study, including the RAND 36-item Health Survey, Center for Epidemiological Studies–Depression Scale, Breast Cancer Prevention Trial Symptom Checklist, Medical Outcomes Study Sleep Scale, and demographic and treatment-related measures. RESULTS: On average, the level of fatigue reported by the breast cancer survivors surveyed (N = 1,957) was comparable to that of age-matched women in the general population, although the breast cancer survivors were somewhat more fatigued than a more demographically similar reference group. Approximately one third of the breast cancer survivors assessed reported more severe fatigue, which was associated with significantly higher levels of depression, pain, and sleep disturbance. In addition, fatigued women were more bothered by menopausal symptoms and were somewhat more likely to have received chemotherapy (with or without radiation therapy) than nonfatigued women. In multivariate analyses, depression and pain emerged as the strongest predictors of fatigue. CONCLUSION: Although the majority of breast cancer survivors in this large and diverse sample did not experience heightened levels of fatigue relative to women in the general population, there was a subgroup of survivors who did report more severe and persistent fatigue. We identified characteristics of these women that may be helpful in elucidating the mechanisms underlying fatigue in this population, as well as directing intervention efforts.
FATIGUE IS ONE OF the most common side effects of cancer treatment, affecting approximately 70% of cancer patients receiving radiation therapy and chemotherapy.1,2 Studies examining the prevalence of fatigue among breast cancer patients have found that up to 99% experience some level of fatigue during the course of radiation therapy and/or chemotherapy, and more than 60% rate their level of fatigue as moderate to severe.3,4 Studies have also shown that the intensity and duration of fatigue experienced by breast cancer patients undergoing treatment is significantly greater than that experienced by healthy controls.4-6 Indeed, fatigue was considered to be the most distressing side effect of treatment in a group of breast cancer patients receiving adjuvant chemotherapy.7 There is growing evidence to suggest that fatigue may persist for months or even years after completion of breast cancer treatment, particularly among patients who have received adjuvant chemotherapy.8,9 The occurrence of fatigue beyond the acute phase of treatment was first noted in studies assessing the long-term quality of life of breast cancer survivors, which found that many women continued to experience feelings of fatigue, reductions in energy, and disruptions in activity level years after diagnosis and treatment.10-13 (Although we realize that "breast cancer survivors" is not a universally accepted term, we use that terminology here for the sake of brevity to refer to women with a history of breast cancer.) These findings have been confirmed in several recent studies that focused specifically on the experience of fatigue in breast cancer survivors using standardized fatigue inventories and reference populations. Andrykowski et al surveyed 88 breast cancer survivors an average of 28 months after treatment and found higher levels of fatigue, more weakness, and less vitality than an age-matched group of women with benign breast problems. Broeckel et al also found higher levels of fatigue in a sample of 61 breast cancer survivors who had completed adjuvant chemotherapy an average of 471 days previously compared with women of similar age with no history of cancer. Fatigue has been shown to have a negative impact on overall quality of life among breast cancer survivors9,12,14 and to cause greater interference with daily functioning in survivors than in healthy controls.6 Fatigue is a nonspecific, multidimensional construct that is generally thought to involve subjective feelings of tiredness, weakness, and/or lack of energy. Numerous factors can cause fatigue, including physical or mental activity, medical conditions, and psychological factors, particularly mood disturbance. In the context of breast cancer, investigators have proposed that fatigue may be caused by the disease itself, by treatment for the disease, by physical symptoms or conditions resulting from the disease or its treatment (eg, menopausal symptoms), and/or by psychological responses to breast cancer.15,16 However, the exact mechanisms underlying the onset and persistence of fatigue in women with breast cancer have not yet been determined. A limited number of studies have examined correlates of fatigue among breast cancer survivors and may provide insight into potential causative factors. Interestingly, medical and treatment-related factors are not consistently associated with fatigue in studies of breast cancer survivors. Several studies found no relationship between fatigue and initial disease stage, type of surgery, length of chemotherapy treatment, or use of tamoxifen.8,9,17 There is mixed evidence for an association between receipt of adjuvant chemotherapy and fatigue; two recent studies reported higher levels of fatigue among former chemotherapy patients compared with those treated with radiation therapy alone,17,18 whereas two others found no differences in fatigue between patients treated with chemotherapy and those treated with radiation therapy.8,11 The length of time since diagnosis and treatment was associated with fatigue levels in only one study, which found a positive correlation between time since treatment and a one-item measure of fatigue.11 Fatigue is a common symptom of depression and has been associated with depressed mood6,8 and the presence of a current mood disorder9 in studies conducted with breast cancer survivors. Other studies have noted a correlation of fatigue with anxiety6 and with illness uncertainty17 among breast cancer survivors. Fatigue has also been associated with symptoms that can emerge or persist after breast cancer treatment, specifically pain14 and menopausal symptoms.9 Sleep problems have been linked with higher levels of fatigue among breast cancer survivors.8,9 In addition, fatigue has been associated with the presence of illnesses unrelated to breast cancer.17 The present study was designed to provide an in-depth examination of fatigue in a large and diverse sample of breast cancer survivors (N = 1,957), all of whom had completed treatment and were disease-free at the time of study. This report describes our findings related to: (1) the occurrence of fatigue in this group relative to general population norms; (2) the impact of fatigue on various components of health-related quality of life; and (3) characteristics of fatigued survivors, which may generate hypotheses about mechanisms underlying fatigue in this population. We focused on psychological factors known to influence fatigue, specifically depression, as well as physical symptoms (pain and menopausal symptoms) and sleep disturbance.
Study Samples and Recruitment Breast cancer survivors were recruited from two large metropolitan cities (Los Angeles, CA, and Washington, DC) to complete survey measures as part of a larger program of research addressing quality of life, sexuality, and intimacy among breast cancer survivors.19,20 Two independent samples of women were studied. Sample 1 included 863 breast cancer survivors recruited between September 1994 and November 1995, and sample 2 included 1,094 breast cancer survivors recruited between January 1996 and June 1997. Women were eligible for participation if they met the following criteria: (1) had been diagnosed with early, resectable breast cancer (stage 0, I, or II at diagnosis); (2) were between 1 and 5 years after initial breast cancer diagnosis; (3) had completed local and/or systemic adjuvant cancer therapy; (4) were currently considered disease-free and were not receiving any cancer therapy other than tamoxifen; (5) had no history of treatment for other cancers, with the exception of noninvasive skin cancer and cervical cancer; (6) could read and write English; (7) could provide informed consent; and (8) had no other major disabling medical or psychiatric conditions that would confound evaluation of health-related quality of life. Potential subjects were identified from tumor registry listings, offices of surgeons and medical oncologists, and hospital and clinic logs. A recruitment letter was sent to each potential subject, including a brief description of the study and a response form on which she indicated her willingness to participate. Women who responded affirmatively were contacted by telephone and screened for eligibility. Eligible women were given more detailed information about the research, including the personal nature of the survey questionnaire, and if still interested, were sent a questionnaire booklet and consent form. More than 50% of women who responded to the initial letter of invitation were included in the final samples. A detailed description of study recruitment procedures and characteristics of respondents and nonrespondents is provided elsewhere.19,20
Measures RAND 36-Item Health Survey 1.0. This self-report measure contains eight individual subscales that represent the three general areas of health-related quality of life: physical, emotional, and social well-being.21,22 The subscales include physical functioning, role function–physical (assessing role limitations caused by physical factors), bodily pain, social functioning, emotional well-being, role function–emotional (assessing role limitations caused by emotional factors), energy/fatigue, and general health perceptions. Each subscale is standardized on a scale from 0 to 100, with higher scores indicating better functioning. The RAND Health Survey was used as the primary measure of health-related quality of life in this report. The energy/fatigue subscale of the RAND 36-item Health Survey consists of four items that assess how much of the time the individual "felt full of pep," "had a lot of energy," "felt worn out," and "felt tired" during the past 4 weeks. As with the other subscales on this instrument, standardized scores on the energy/fatigue subscale range from 0 to 100, with higher scores indicating better functioning (ie, higher levels of energy). The energy/fatigue subscale is bipolar in nature: scores greater than the midpoint of 50 represent well-being, whereas scores less than 50 represent limitations or disability related to fatigue. Thus, a score of 100 is only earned by individuals who report feeling full of pep and energy all of the time, and a score of 0 is earned only by those who report feeling tired and worn out all of the time.23 In a previous study of breast cancer survivors,8 the energy/fatigue subscale of the RAND Health Survey correlated highly with other fatigue measures (ie, Chalder Fatigue Scale, Piper Fatigue Scale) and discriminated between breast cancer survivors and women with benign breast problems.
CES-D.
This 20-item self-report questionnaire was designed by Radloff24 to assess depressive symptomatology in the general population. Respondents indicate how often they have experienced a variety of symptoms during the past week on a four-point scale ranging from "rarely or none of the time" to "most or all of the time." Higher scores on this measure indicate higher levels of depressive symptomatology, with scores BCPT Symptom Checklist. This is a 43-item list of commonly reported physical and psychological symptoms developed specifically for the BCPT.25 Respondents indicate how much they have been bothered by each symptom in the past 4 weeks on a four-point scale ranging from "not at all" to "extremely." For this study, we used only those items that assessed vasomotor symptoms (hot flashes, night sweats). Because of skewed distributions, responses to these items were coded categorically (present/not present). MOS Sleep Scale. This is a nine-item self-report measure that assesses sleep disturbance, including problems with initiation and maintenance of sleep, perceived adequacy of sleep, and daytime somnolence.26 Respondents indicate how often they have experienced each of the problems listed in the past 4 weeks on a six-point scale ranging from "none of the time" to "all of the time." This measure was administered in sample 1 only. Demographic and medical data. Information on demographics, medical conditions and medications, menstrual and gynecologic history, and breast cancer treatment was obtained by self-report. Because the survey was primarily focused on issues related to quality of life, detailed information on disease- and treatment-related factors (eg, stage of disease, number of positive nodes, type and length of chemotherapy treatment) was not collected.
Statistical Methods
Sample Characteristics Demographic and treatment-related characteristics of women in samples 1 and 2 are listed in Table 1. The mean age in both samples was 55 years, although the age distributions were slightly different in each group. The large majority of women in each sample were white, with a smaller number describing themselves as black or "other" (primarily Hispanic or Asian–Pacific Islander). The ethnic distribution of each sample is representative of women with early-stage breast cancer in the two cities from which these women were recruited. More than two thirds of the women in each sample were either married or in a significant relationship at the time of questionnaire completion, with a slightly higher percentage of partnered women in sample 2. The majority of women in both samples had gone to college, and one third had obtained postgraduate training. Almost one half of the women in both samples were employed full-time; the remainder were employed part-time or were full-time homemakers, retired, or "other" (ie, unemployed, permanently disabled, on temporary medical leave, students, or volunteers). Approximately two thirds of both samples had a yearly household income of more than $45,000.
The majority of women in each of the two samples were treated with a combination of surgery and radiation therapy. Differences in the type of treatment received were notable primarily for a higher rate of surgery alone in sample 1 and a higher rate of surgery with both radiation therapy and adjuvant chemotherapy in sample 2. This change reflects temporal patterns of increasing use of adjuvant therapy for patients with stage I disease. Approximately one half of the women in each group were receiving tamoxifen at the time of study. On average, slightly more time had elapsed since initial breast cancer diagnosis for women in sample 1 compared with those in sample 2 (mean 3.00 and 2.83, respectively; P = .001).
Fatigue and Health-Related Quality of Life
We next compared the level of energy/fatigue reported by our combined sample of survivors to that observed in reference groups of noninstitutionalized women. Two sources of reference data were available: MOS national norms for age-matched women in the general population (N = 1,953)23 and baseline data from women at high risk for breast cancer participating in the BCPT (N = 9,749).25 Women enrolled onto the BCPT were primarily white, married, and well-educated, whereas women in the MOS norm group were more representative of the general United States population in terms of their sociodemographic characteristics. Figure 1 shows the RAND Health Survey profiles for our breast cancer survivors, the MOS norm group, and the BCPT. The breast cancer survivors reported slightly higher levels of energy than women in the general population (mean, 60.0 and 58.5, respectively; P = .009). In contrast, the survivors reported lower levels of energy than BCPT participants (mean, 60.0 and 67.4, respectively; P = .0001). A comparison of scores on the other quality-of-life subscales indicated that BCPT participants reported the highest levels of functioning overall, followed by the breast cancer survivors and then women in the MOS norm group.
In addition to evaluating the level of fatigue experienced by this group of women, we were interested in examining the association between fatigue and other components of quality of life. Results showed significant correlations between energy/fatigue and each subscale of the RAND Health Survey, including physical functioning (r = .44), emotional well-being (r = .59), role limitations caused by physical (r = .50) and emotional (r = .46) factors, social functioning (r = .54), and general health perceptions (r = .57; all P = .0001). In each domain, we found that women who were more fatigued (ie, had lower scores on the energy/fatigue scale) rated their quality of life at a lower level.
Characteristics of Fatigued Survivors We first examined the association between being fatigued and demographic variables of interest. Fatigue was significantly associated with age, income level, and relationship status (Table 3). Women in the fatigued group were slightly younger, had a lower yearly income, and were less likely to be married or in a significant relationship than those in the nonfatigued group (all P < .05). Ethnicity, educational attainment, and employment status were not associated with fatigue. We also examined the relationship between fatigue and several chronic, non–cancer-related medical problems, including diabetes, arthritis, headache, heart problems, and high blood pressure (data not shown). Women in the fatigued group had higher rates of arthritis, headache, and heart disease than those in the nonfatigued group (all P < .05).
Bivariate analyses showed a modest association between fatigue and type of treatment received (Table 3). Women in the fatigued group were more likely to have been treated with a combination of chemotherapy and radiation therapy or with chemotherapy alone than those in the nonfatigued group. In contrast, women in the nonfatigued group were more likely to have been treated with radiation alone or with surgery alone. No differences were observed between the two groups with regard to use of tamoxifen. In addition, we found no association between fatigue and the number of years since initial diagnosis or the year of initial diagnosis (which could impact the type of chemotherapy received). We were somewhat surprised that fatigue was not more strongly associated with the type of treatment received and conducted exploratory analyses to examine the course of fatigue in women treated with different therapy regimens. In particular, we wanted to determine whether women treated with adjuvant chemotherapy reported more enduring fatigue than those treated with radiation therapy or surgery alone. We compared the level of fatigue reported by women in each of the four treatment categories surveyed at 1, 2, 3, 4, and 5 years after diagnosis. A similar pattern of fatigue scores was observed among women treated with radiation therapy, chemotherapy, or both: energy levels were relatively low at 1 year postdiagnosis (ie, mean energy/fatigue score < 57), increased at 2 years postdiagnosis, and remained relatively stable for years 3, 4, and 5. In contrast, there was no evidence of a decrease in energy at 1 year post-diagnosis among women treated with surgery alone. A one-way analysis of variance comparing women at 1 year postdiagnosis showed that women who received radiation and/or chemotherapy reported higher levels of fatigue than those who received surgery alone at this time point (F1,276 = 5.32; P = .02). After 1 year, the difference in fatigue scores associated with treatment was no longer significant. Fatigue was strongly associated with bodily pain, as assessed by the pain subscale of the RAND Health Survey (Table 3). Fatigued women reported significantly more severe and disabling pain than did those in the nonfatigued group, and thus scored lower on this measure. In addition, fatigue was significantly associated with the two menopausal symptoms assessed: hot flashes and night sweats. As listed in Table 3, women in the fatigued group were more likely to have been bothered by hot flashes and night sweats in the last month than those in the nonfatigued group. There was also a significant association between fatigue and sleep (analyses conducted for sample 1 only). Fatigued women in sample 1 reported significantly more problems with sleep than nonfatigued women (P < .0001), including greater sleep disturbance (ie, problems with initiation and maintenance of sleep), lower perceived adequacy of sleep, and particularly greater somnolence during the day. We found a strong association between fatigue and depression, with women in the fatigued group reporting significantly higher levels of depressive symptomatology than those in the nonfatigued group (Table 3). The mean CES-D score for women in the fatigued group was greater than the clinical cutoff score of 16, indicating the presence of clinically significant depressive symptoms. The association between fatigue and depression did not seem to be caused by an overlap in items on the two scales because these measures were strongly correlated even after excluding fatigue-related items on the CES-D (ie, "I felt that everything I did was an effort," "I could not get going").
To explore further the association between fatigue and depression, we examined individual scores on the energy/fatigue subscale of the RAND Health Survey and the CES-D. We found that there was a small group of women who reported high levels of depressive symptomatology but did not seem to be fatigued (ie, had high energy) and, conversely, a small group of women who reported high levels of fatigue but did not seem to be experiencing symptoms of depression. Exploratory analyses were conducted to compare these groups on various quality-of-life domains. Women were classified as fatigued/not depressed if they scored
Logistic Regression The overall model was highly significant (P = .0001). Results for the individual predictor variables are listed in Table 4. The strongest predictor of fatigue group membership was depression, followed by pain. Neither type of treatment received nor presence of menopausal symptoms was associated with fatigue in the multivariate model. Of the control variables assessed, arthritis, high blood pressure, and age emerged as significant predictors of fatigue group membership. Consistent with the bivariate analyses, individuals who had arthritis or high blood pressure, or who were younger, were more likely to be classified as fatigued.
These results demonstrate the importance of depression as a predictor of fatigue, even after controlling for the effect of other predictor variables. To illustrate this effect, consider two women who have identical scores on all of the predictor variables except depression. If both women are aged 56 years, partnered, experiencing menopausal symptoms, have arthritis, had surgery with radiation therapy, and have a pain score of 78.63 (the sample mean), the probability of being classified as fatigued would be 28% for the woman whose depression score was 8, versus 50.6% for the woman whose depression score was 16.
This study represents the largest-scale examination of fatigue in breast cancer survivors conducted to date, including data from almost 2,000 breast cancer survivors collected in two independent samples between 1994 and 1997. Our results suggest that fatigue was not a significant problem for the majority of survivors in this sample; on average, these women did not report feeling tired or worn out in the past 4 weeks, nor was their mean score on the energy/fatigue scale substantially different from that of an age-matched control group. When present, fatigue was closely linked to depression and was also strongly associated with bodily pain and sleep disturbance. Treatment-related factors such as receipt of adjuvant chemotherapy and presence of menopausal symptoms were less consistently associated with fatigue, with significant associations emerging in bivariate but not multivariate regression analyses. The treatment differences were apparent among more recently diagnosed and treated patients and dissipated over time. It is important to note that these findings were obtained from a volunteer research sample and thus may not be generalizable to all breast cancer survivors. In particular, women who responded to the initial recruitment letter were more likely to be white, married, and younger than those who did not respond, which may have biased the study results. One of the initial questions we addressed was whether the level of fatigue reported by survivors in this sample was more severe than that observed in reference populations. Based on previous research,8,9 we hypothesized that fatigue would be more prevalent and prominent among breast cancer survivors than healthy women of similar age, demographic characteristics, and socioeconomic status. Our results provide only minimal support for this hypothesis. An examination of scores on the energy/fatigue scale of the RAND Health Survey indicated that survivors in this study were not more fatigued than an age-matched group of women from the general population.23 The survivors did seem to be somewhat more fatigued (or more accurately, to have less energy) than a healthy group of women at risk for breast cancer participating in the BCPT.25 The BCPT arguably provides the most appropriate reference point for the breast cancer survivors surveyed here, given the similarity between these groups in terms of demographic and socioeconomic characteristics. These groups are also comparable in that both are composed of highly motivated research participants. Overall, these results suggest that fatigue may be somewhat more prominent in breast cancer survivors than would be expected based on demographic and socioeconomic factors but is not necessarily more severe than that observed in the general population. It would also be informative to compare breast cancer survivors with women who had faced a similar type of life-threatening crisis in the past, as well as women who had undergone similar medical procedures that were not life-threatening, to evaluate better the unique contribution of breast cancer diagnosis and treatment to fatigue. These findings diverge somewhat from other reports in the literature that have shown significant differences in fatigue between long-term breast cancer survivors and women with no history of breast cancer.8,9 This discrepancy may, in part, be a result of differences in measurement techniques; other investigators have used a variety of measures to assess fatigue (eg, Profile of Mood States Fatigue Scale, Fatigue Symptom Inventory, Chalder Fatigue Scale, Piper Fatigue Scale) in contrast to the single, four-item scale used in this report, and may have captured aspects of this complex phenomenon that we did not. In addition, it is possible that differences in sociodemographic characteristics of the samples assessed, as well as the geographic locations from which the samples were drawn, may have influenced results from various groups.
Overall, our findings related to the occurrence of fatigue are consistent with our earlier studies on quality of life among breast cancer survivors20 and suggest that the majority of survivors are functioning well in this as in other quality-of-life domains. However, there was a substantial minority of survivors who did seem to be experiencing more prominent and persistent fatigue. Approximately one third of the women we surveyed scored in the "limitations/disability" range of the energy/fatigue scale, indicating that they felt tired and lacked energy at least some of the time over the past 4 weeks. Consistent with these findings, Lindley et al28 found that approximately 30% of the breast cancer survivors they assessed reported moderate to severe fatigue Currently, little is known about the mechanisms underlying the occurrence of fatigue in cancer patients and survivors. As a first step toward identifying potential causal factors for fatigue among breast cancer survivors, we compared fatigued and nonfatigued survivors on a variety of treatment-related and psychosocial variables. One of the primary candidates for causing fatigue in this population is cancer treatment, particularly treatment with adjuvant chemotherapy. Although bivariate analyses did show a weak association between type of treatment and fatigue, treatment did not emerge as a significant predictor of fatigue in the logistic regression analysis. In addition, the length of time since diagnosis did not discriminate between fatigued and nonfatigued survivors, as might be expected if treatment was a primary cause of fatigue. Treatment seemed to play a role primarily in the early recovery period, as women receiving radiation therapy and/or chemotherapy reported higher levels of fatigue only in the first year after diagnosis. Our results suggest that treatment is not a primary contributor to enduring fatigue in breast cancer survivors. Because the type and duration of chemotherapy were not assessed in this report, it is unclear whether the intensity of chemotherapy received had any impact on fatigue levels. Although only a small number of women in our sample were likely to have been treated with very high-dose chemotherapy (because of the early stage of their disease), it is possible that those who received more intensive chemotherapy regimens may have experienced more fatigue. Another factor not assessed here that may have a potent impact on fatigue is risk of cancer recurrence. Women at highest risk may not only receive more intensive cancer treatments but may also experience greater and more prolonged psychological distress because they continue to worry about their future health after completion of treatment. More detailed treatment and disease-related data should be collected in future research. Overall, treatment-related factors accounted for a relatively small portion of the variance in fatigue. Instead, the strongest predictor of fatigue in both bivariate and multivariate analyses was depression. Results showed that women classified as fatigued scored more than two times higher on the depression rating scale than those who were not fatigued. Indeed, the mean depression score for the fatigued group fell into the clinical range of this scale, suggesting that these women were, on average, experiencing clinically significant symptoms of depression. The association between fatigue and depression is complex; fatigue can occur as a symptom of depression or may precipitate feelings of depression because of its interference with mood, work, and leisure activities. In addition, both fatigue and depression may be symptoms of an underlying biologic or disease state. Clearly, more detailed descriptive and prospective studies are required to untangle the association between these constructs and to explore potential common mechanisms that may underlie both. Our data suggest that although fatigue is not equivalent to depression, it is closely linked to symptoms of depression in breast cancer survivors, particularly those who are otherwise healthy. From a clinical perspective, these findings highlight the importance of carefully screening for depression and other psychiatric disorders in cancer survivors who complain of fatigue. Many of these individuals can be treated effectively with medication and/or psychotherapy. Depressed patients can be identified by inquiring about depressed mood, anhedonia, and other symptoms of depression that have been present most of the day, nearly every day for at least a 2-week period.29 Another factor that may contribute to fatigue severity in former cancer patients is the occurrence of treatment-related symptoms. We found that a general measure of bodily pain was a strong predictor of fatigue in this sample of breast cancer survivors, consistent with previous research.3,14,30 Pain can occur secondary to surgery or radiation therapy31 and may lead to fatigue through its effects on mood, activity level, and/or sleep. We were able to assess directly the association between sleep and fatigue only in sample 1. Bivariate analyses conducted in this sample showed a strong association between sleep problems and fatigue, supporting the importance of sleep disturbance in initiating and maintaining fatigue in this population. Sleep was also a significant predictor of fatigue in logistic regression analyses conducted in sample 1 (analyses not shown). Interestingly, although the inclusion of sleep in the regression model did diminish the strength of the association between depression, pain, and fatigue, these variables were still significant predictors of fatigue group membership. Thus, sleep disturbance, depression, and pain may each independently contribute to fatigue severity among breast cancer survivors. In conclusion, results from this study offer good news for breast cancer patients, suggesting that the majority of women do not experience prominent or disabling fatigue after treatment for early-stage breast cancer. However, there is a substantial minority of survivors who do report more severe and enduring fatigue. The negative association between fatigue and overall quality of life observed in this and other studies highlights the importance of identifying and treating this group of fatigued women. Although cross-sectional, results from this study may be useful in directing intervention efforts for cancer-related fatigue. In particular, our findings suggest that treating depression and pain, both of which were strongly associated with fatigue, may be useful in combating fatigue in cancer survivors.
Supported by grant no. RO1 CA63028 from the National Cancer Institute, Bethesda, MD.
1. Smets EMA, Garssen B, Schuster-Uitterhoeve AL, et al: Fatigue in cancer patients. Br J Cancer 68:220-224, 1993[Medline] 2. Vogelzang NJ, Breitbart W, Cella D, et al: Patient, caregiver, and oncologist perceptions of cancer-related fatigue: Results of a tripart assessment survey. Semin Hematol 34:S4–S12, 1997 (suppl 2) 3. Blesch KS, Paice JA, Wickham R, et al: Correlates of fatigue in people with breast or lung cancer. Oncol Nurs Forum 18:81-87, 1991[Medline] 4. Irvine D, Vincent L, Graydon JE, et al: The prevalence and correlates of fatigue in patients receiving treatment with chemotherapy and radiotherapy. Cancer Nurs 17:367-378, 1994[Medline] 5. Irvine DM, Vincent L, Graydon JE, et al: Fatigue in women with breast cancer receiving radiation therapy. Cancer Nurs 21:127-135, 1998[Medline] 6. Hann DM, Jacobsen P, Azzarello LM, et al: Measurement of fatigue in cancer patients: Development and validation of the Fatigue Symptom Inventory. Qual Life Res 7: 301-310, 1998[Medline]
7.
Knopf MT: Physical and psychologic distress associated with adjuvant chemotherapy in women with breast cancer. J Clin Oncol 4:678-684, 1986 8. Andrykowski MA, Curran SL, Lighner R: Off-treatment fatigue in breast cancer surivors: A controlled comparison. J Behav Med 21:1-18, 1998[Medline] 9. Broeckel JA, Jacobsen PB, Horton J, et al: Characteristics and correlates of fatigue after adjuvant chemotherapy for breast cancer. J Clin Oncol 16:1689-1696, 1998[Abstract] 10. Beisecker AE, Cook MR, Ashworth J: Side effects of adjuvant chemotherapy: Perceptions of node-negative breast cancer patients. Psychooncology 6:85-93, 1997[Medline] 11. Berglund G, Bolund C, Fornander T, et al: Late effects of adjuvant chemotherapy and postoperative radiotherapy on quality of life among breast cancer patients. Eur J Cancer 27:1075-1081, 1991 12. Dow KH, Ferrell BT, Leigh S: An evaluation of the quality of life among long-term survivors of breast cancer. Breast Cancer Res Treat 39:261-273, 1996[Medline] 13. Meyerowitz BE, Watkins IK, Sparks FC: Psychosocial implications of adjuvant chemotherapy: A two-year follow-up. Cancer 52:1541-1545, 1983[Medline] 14. Ferrell BR, Grant MM, Funk BM, et al: Quality of life in breast cancer survivors: Implications for developing support services. Oncol Nurs Forum 25:887-895, 1998[Medline] 15. Glaus A: Fatigue in patients with cancer. Recent Results Cancer Res 145:3-26, 1998 16. Miaskowski C, Portenoy RK: Update on the assessment and management of cancer-related fatigue. Principles Practice Supportive Oncol Updates 1:1-10, 1998 17. Mast ME: Correlates of fatigue in survivors of breast cancer. Cancer Nurs 21:136-142, 1998[Medline] 18. Woo B, Dibble SL, Piper BF, et al: Differences in fatigue by treatment methods in women with breast cancer. Forum 25:915-920, 1998 19. Ganz PA, Rowland JH, Meyerowitz BE, et al: Impact of different adjuvant therapy strategies on quality of life in breast cancer survivors. Recent Results Cancer Res 152:396-411, 1998[Medline] 20. Ganz PA, Rowland JH, Desmond KA, et al: Life after breast cancer: Understanding women’s health-related quality of life and sexual functioning. Oncol 16:501-514, 1998 21. Hays RD, Sherbourne CD, Mazel RM: The RAND 36-Item Health Survey 1.0. Health Econ 2:217-227, 1993[Medline] 22. Ware JE Jr, Sherbourne CD: A 36-item Short Form Health Survey (SF-36): I. Conceptual framework and item selection. Med Care 30:473-483, 1992[Medline] 23. Ware JE Jr: SF-36 Health Survey: Manual and Interpretation Guide. Boston, MA,Nimrod Press, 1993 24. Radloff LS: The CES-D Scale: A self-report depression scale for research in the general population. Appl Psychol Measur 1:385-401, 1977
25.
Ganz PA, Day R, Ware JE Jr, et al: Base-line quality-of-life assessment in the National Surgical Adjuvant Breast and Bowel Project Breast Cancer Prevention trial. J Natl Cancer Inst 87:1372-1382, 1995 26. Hays RD, Stewart AL: Sleep measures, in Stewart AL, Ware JE Jr (eds): Measuring Functioning and Well-Being: The Medical Outcomes Study Approach. Durham, NC,Duke University Press, 1992, pp 235-259 27. Kelsey JL, Thompson WD, Evans AS: Methods in Observational Epidemiology. New York, NY,Oxford University Press, 1986
28.
Lindley C, Vasa S, Sawyer WT, et al: Quality of life and preferences for treatment following systemic adjuvant therapy for early stage breast cancer. J Clin Oncol 16:1380-1387, 1998 29. American Psychiatric Association:Diagnostic and Statistical Manual of Mental Disorders (ed 4). Washington, DC,American Psychiatric Association, 1994, pp 339-344 30. Spiegel D, Sands S, Koopman C: Pain and depression in patients with cancer. Cancer 74:2570-2578, 1994[Medline] 31. Maunsell E, Brisson J, Deschenes L: Arm problems and psychological distress after surgery for breast cancer. Can J Surg 36:315-320, 1993[Medline] Submitted May 13, 1999; accepted October 29, 1999.
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Copyright © 2000 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
16 indicating potentially significant levels of depression.
2 tests were used to evaluate associations among categoric variables. Student’s t tests were used to compare means of continuous variables for two groups, and one-way analysis of variance was used to compare means of continuous variables for three or more groups. Logistic regression was used to estimate the predictive power of key medical and quality of life–related variables on the likelihood of being fatigued. 
50 on the energy/fatigue scale and less than the clinical cutoff of 16 on the CES-D (n = 337). Women were classified as nonfatigued/depressed if they scored greater than 50 on the energy/fatigue scale and greater than 16 on the CES-D (n = 145). Student’s t tests comparing these groups on the RAND Health Survey indicated that women in the fatigued/nondepressed group showed greater impairments in physical health, including poorer physical functioning, more limitations caused by physical problems, and poorer general health. Women in the fatigued/nondepressed group were also significantly more likely to experience arthritis, which could account, in part, for the lower levels of physical functioning observed. In contrast, women in the depressed/nonfatigued group showed greater impairments in mental health, including lower levels of emotional well-being, more limitations caused by emotional problems, and lower levels of social functioning. 
