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Journal of Clinical Oncology, Vol 25, No 13 (May 1), 2007: pp. 1713-1721 © 2007 American Society of Clinical Oncology. DOI: 10.1200/JCO.2006.09.5083 Randomized Trial of Exercise Therapy in Women Treated for Breast Cancer
From the Department of Primary Care and General Practice, The Medical School, University of Birmingham, Birmingham; The Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield; Sport Culture and the Arts, University of Strathclyde, Glasgow; and Clinical Oncology, Weston Park Hospital, Sheffield, United Kingdom Address reprint requests to Amanda Daley, PhD, The Department of Primary Care and General Practice, Medical School, Clinical Sciences Building, University of Birmingham, Birmingham, B15 2TT United Kingdom; e-mail: a.daley{at}bham.ac.uk
Purpose To examine the effects of aerobic exercise therapy on quality of life (QoL) and associated outcomes in women treated for breast cancer. Evidence suggests that exercise may be beneficial, but no trial has included an exercise-placebo and a usual-care group to control for the attention effects that might be associated with aerobic exercise interventions in cancer patients. Patients and Methods A total of 108 women who had been treated for breast cancer 12 to 36 months previously were randomly assigned to supervised aerobic exercise therapy (n = 34), exercise-placebo (body conditioning; n = 36), or usual care (n = 38). Exercise therapy and exercise-placebo sessions took place three times per week for 8 weeks. Outcomes included QoL, depression, exercise behavior, aerobic fitness; outcomes were assessed at baseline and at the 8- and 24-week follow-up. Results Analyses of covariance revealed a significant mean difference of 9.8 units in Functional Assessment of Cancer TherapyGeneral (primary outcome) favoring aerobic exercise therapy at 8 weeks, relative to usual care. Significant differences that favored aerobic exercise therapy relative to usual care were recorded for Functional Assessment of Cancer TherapyBreast, social/family well-being, functional well-being, and breast cancer subscale scores at 8-week follow-up. Psychological health outcomes improved modestly for both intervention groups; these improvements were sustained for several end points. Conclusion Exercise therapy had large, clinically meaningful, short-term beneficial effects on QoL in women treated for breast cancer; this finding cannot be attributable to attention, given that the exercise-placebo group did not report similar effects relative to usual care.
Survival rates for breast cancer have been improving for more than 20 years and this appears likely to continue.1 The estimated relative 5-year survival rate for women diagnosed in England and Wales in 2001 to 2003 was 80%.1 However, breast cancer and its treatment sequelae are associated with significant changes in quality of life (QoL) and well-being2 that may persist for many years.3,4 Exercise interventions may be particularly appropriate in cancer populations because they have the potential to improve physical and psychological health simultaneously. Systematic review evidence5-8 seems to favor QoL benefit from exercise, but reviews have raised concerns about the methodologic quality of previous studies. Improvements in QoL could be attributable to the increased attention given to cancer patients involved in exercise interventions, and a recent systematic review6 highlighted the need for trials to include appropriate comparison groups to rule out the possibility of such effects. This is likely to be more of a concern in studies that involved a no-treatment usual-care arm. To date only four studies9-12 have been designed to have at least partial ability to answer this question in cancer patients, but none included both exercise-placebo and usual-care comparison groups. Such comparisons provide the most rigorous examination of the efficacy of aerobic exercise as a QoL-enhancing intervention. This trial13 was designed to address some of methodologic shortfalls of previous research.
Participants, Recruitment Strategies, and Eligibility The trial methodology has been reported previously.13 The primary recruitment strategy was by postal invitation letter from patients' treating oncologist or surgeon, who identified potentially eligible patients from hospital records. Secondary recruitment strategies involved media advertisements and presentations to cancer support groups and breast cancer nurses. Women who were not regularly active and who had been treated for localized breast cancer 12 to 36 months previously were eligible. Women with metastases and inoperable or active locoregional disease were ineligible (clinician determined). The local research ethics committee provided ethical approval.
Additional Eligibility Screening
Random Assignment to Treatment and Assessments
Trial Interventions
Exercise-Placebo and Usual Care
Primary Outcome
Secondary Outcomes Aerobic fitness was measured using the submaximal, 8-minute, single-stage walking test25 performed on a treadmill. Assessments of height, weight, and percentage body fat using bioelectrical impedance analysis were included as indicators of body composition. Measurements of muscle function using a Biodex isokinetic machine (Biodex System 3 Dynamometer; Biodex Medical Systems Inc, Shirley, NY) were also taken (not reported here).
Adherence to the Interventions
Baseline Characteristics
Sample Size Calculations and Statistical Analyses
Data were analyzed on an intention-to-treat basis. Repeated-measures mixed analysis was used to compare the majority of trial outcomes between the groups at 8- and 24-week follow-up. Treatment alone and in combination with time were considered as fixed effects, with baseline measurement as a covariate, time (8 and 24 weeks) as a repeated factor, and participants as the random factor. Paired comparisons between the groups at each time point were adjusted by the Tukey-Kramer method. The physical activity and SOC data were analyzed with
Trial Participants and Baseline Characteristics Recruitment took place between January 2003 and July 2005 (Fig 1). The estimated trial recruitment rate of eligible patients was 28.6%.28 One hundred eight eligible patients were randomly assigned to exercise therapy (n = 34), exercise-placebo (n = 36), or usual care (n = 38). The groups were generally balanced at baseline in relation to demographic, treatment, health behavior, and outcome variables (Tables 1 and 2).
Follow-Up Follow-up was achieved on 93% of participants at 8-weeks and 89% at 24 weeks. Little's D test indicated that missing data were missing completely at random ( 2 = 88.2; df = 1,290; P = .99).
QoL Outcomes
Psychological Health Outcomes A significant difference between exercise-placebo and usual care in total fatigue scores at 8 weeks was noted; the usual-care group had higher scores (P = .037). A significant mean difference for physical conditioning competence between the exercise therapy and usual-care groups was recorded at both follow-ups, with a reduction in effect at 24 weeks (P < .01 in both cases). Analyses also revealed a significant difference in physical self-worth scores between exercise therapy and usual care (P = .003) and between exercise-placebo and usual care at 8 weeks (P = .005). Significant differences in mean depression scores between exercise therapy and usual care (P = .001) and also between exercise-placebo and usual care (P = .001) were recorded; usual care reported higher depression scores. Larger effects were seen at 8 weeks but these benefits persisted at 24 weeks. A significant difference in mean satisfaction with life scores between exercise-placebo and usual care was noted at 24 weeks (P = .0017; Table 4).
Physical Health Outcomes and Physical Activity Evidence of significant differences in aerobic fitness scores were recorded between exercise therapy and usual care (P = .002) and exercise-placebo and usual care (P = .021) at 8 weeks (Table 4). Significant differences in the percentage of participants increasing their physical activity to become active at least three times per week between exercise therapy and usual care were recorded at the 8-week (P < .001) and 24-week follow-up (P < .001), and also between exercise-placebo and usual care (8 weeks, P < .001; 24 weeks, P = .01); usual care reported less physical activity. A greater proportion of exercise therapy participants moved to the action or maintenance SOC compared with usual care at 24 weeks (P < .001). A similar effect between exercise-placebo and usual care (P = .03) was also recorded (Table 5).
Bootstrapping of Trial Outcomes The variables physical well-being, SWB, satisfaction with life, sport competence, physical conditioning competence, physical appearance, and strength competence were found to have skewed distributions; however, bootstrapping confirmed that P values from the mixed-model analysis were stable and therefore correct inferences could be made from the results.
Adherence to the Interventions and Amount of Exercise
The primary finding of the study was that a supervised aerobic exercise therapy intervention significantly improved QoL (FACT-G) in previously inactive women treated for breast cancer, relative to usual care. Differences substantially exceeded the minimally important difference29 of 5 to 6 units for the FACT-G scale at 8 weeks. These findings cannot be attributable to attention effects because the exercise-placebo group did not report significant benefit, compared with usual care. The magnitude of the effect for FACT-G was far greater than those reported for other types of health-enhancing and QoL interventions (eg, psychological support in cancer patients).30 Furthermore, the efficacy of psychosocial interventions in cancer care has been questioned recently,31,32 and studies33 have reported that such interventions do not decrease health care use costs in breast cancer patients; these results strengthen the case for the evaluation of the merits of alternative QoL interventions such as exercise. Given that research has demonstrated that women who engage in exercise decrease their risk of breast cancer reoccurrence,34 interventions involving exercise take on even greater health importance. We found significant effects for specific components of QoL; namely SWB, FWB, and BCS, and these generally favored exercise therapy, relative to usual care. These findings are consistent with previous reports9-10,27 that have found QoL benefits resulting from participation in exercise programs in women undergoing and recovering from breast cancer treatment. The results for FWB are particularly promising, given that physical functioning is considered one of the most important components of QoL in cancer patients.35 Recent research has reported that high economic costs are associated with functional impairment in breast cancer patients,36 and participation in regular aerobic exercise may serve to expedite the recovery process. However, we are mindful that this study only demonstrated short-term gains in these outcomes. Intervention-related improvements in psychological health outcomes were modest but sustained for several end points. The exercise therapy group reported better perceived physical conditioning competence scores than usual care at both follow-ups. Both exercise therapy and exercise-placebo reported higher physical self-worth scores than usual care, but the magnitude of the effect was greater for exercise therapy. Depression scores were significantly lower in exercise therapy and exercise-placebo compared with usual care at both follow-ups. Only a small benefit for depression beyond the effects of the exercise-placebo condition was noted. We cannot rule out the possibility that light body conditioning and stretching exercises of minimal aerobic exertion also provide psychological benefit to cancer patients; indeed, recent pilot trials37,38 have suggested that activities such as yoga and tai chi significantly improve psychological well-being in breast cancer patients. Additional research should pursue this issue. We found no group differences for fatigue at follow-up between exercise therapy and usual care, although a difference between exercise-placebo and usual care was noted. These findings are supported by some studies but are inconsistent with others.9,11 The nonsignificant findings for body composition outcomes were not surprising, given the short intervention period, and are consistent with systematic review evidence8 that has indicated no statistically or clinically significant changes in body weight or body mass index in exercise trials involving breast cancer patients. It may be that more direct and accurate assessments (eg, dual x-ray absorptiometry) of body composition are required to be able to detect these outcomes.39 Although the exercise therapy group demonstrated improved aerobic fitness scores at 8-week follow-up, a significant effect was also seen in the exercise-placebo group, albeit somewhat smaller. There are several possible explanations for this. Given that blinded assessments of outcomes were not a feature of this study, it may be that a Hawthorne effect or a test-retest effect has occurred. It is also possible that the exercise-placebo intervention provided women with aerobic benefit; this explanation seems unlikely, however, given that we know this group worked at less than 40% heart rate reserve. Interestingly, in a trial that compared psychotherapy with psychotherapy plus exercise arms,9 both groups were found to improve their cardiovascular endurance, highlighting further the importance of including placebo groups in behavioral/lifestyle-based trials. Exercise therapy and exercise-placebo participants significantly increased their physical activity at both follow-ups, relative to usual care, but the greatest difference was recorded between exercise therapy and usual care. A similar pattern of results was also observed for SOC, with the magnitude of change also larger for exercise therapy than other trial groups. Nevertheless, the data indicated that some intervention contamination had occurred in the exercise-placebo and usual-care groups. To some extent, contamination in the exercise-placebo group was inevitable, given that this group believed they had been assigned to an active exercise arm; consequently, it seems they increased their activity outside of placebo intervention sessions, even though they were asked not to do so. Contamination may also explain the increases in aerobic fitness observed in the exercise-placebo group. Blinding of the assessments was not possible, although we do not consider this to be a substantial limitation because the primary outcome questionnaire was self-administered. Although the trial was underpowered for the primary outcome, and despite intervention contamination, we were still able to report a significant effect of the magnitude we expected. The low level of attrition across follow-ups was encouraging. This was the first published trial of the benefits of exercise in cancer patients to include both exercise-placebo and usual-care control groups; we regard this was a particular strength over previous studies. Past studies that have examined the effects of exercise interventions in cancer patients generally have failed to provide detailed information about the nature and content of the exercise sessions; without such information it is difficult to know the amount of exercise that is likely to provide benefit to cancer patients. We obtained excellent adherence to the interventions. The study was not statistically powered to detect differences between the intervention groups; therefore, any inferences about such differences should be made with caution until such a trial takes place. Although we adjusted for paired comparisons between groups, there exists the possibility of a type I error due to multiple statistical testing and reported differences may be spurious, but the consistent trends toward benefit for exercise therapy suggests differences, where identified, are real. Use of the same researcher in both interventions subjected the study to potential intervener expectancy effects. In summary, in women treated for breast cancer in the United Kingdom, we report large, clinically important, short-term benefits in QoL from participation in exercise therapy. Longer term effects in a number of other outcomes were also found, relative to usual care. Attention effects do not appear responsible for the QoL benefits associated with participation in aerobic exercise in this population, but researchers should consider the possibility that attention effects, at least in part, are responsible for some of the psychological benefits experienced by cancer patients who engage in exercise programs.
The authors indicated no potential conflicts of interest.
Conception and design: Amanda J. Daley, John M. Saxton, Nanette Mutrie, Robert Coleman Financial support: Amanda J. Daley, John M. Saxton, Nanette Mutrie Administrative support: Amanda J. Daley, Helen Crank Provision of study materials or patients: Amanda J. Daley, Helen Crank, Robert Coleman Collection and assembly of data: Amanda J. Daley, Helen Crank Data analysis and interpretation: Amanda J. Daley, Helen Crank, John M. Saxton, Nanette Mutrie, Andrea Roalfe Manuscript writing: Amanda J. Daley, Helen Crank, John M. Saxton, Nanette Mutrie, Robert Coleman, Andrea Roalfe Final approval of manuscript: Amanda J. Daley, Helen Crank, John M. Saxton, Nanette Mutrie, Robert Coleman, Andrea Roalfe
We thank the patients who agreed to participate in this trial. We also thank Malcolm Reed, MD, and Stan Kohlhardt, MD, for assistance with patient recruitment, and Sue Green for her assistance with the interventions.
Supported by Grant No. CE8304 from Cancer Research UK. Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.
1. Coleman MP, Rachet B, Woods LM, et al: Trends and socioeconomic inequalities in cancer survival in England and Wales up to 2001. Br J Cancer 90:1367-1373, 2004[CrossRef][Medline] 2. Burgess C, Cornelius V, Love S, et al: Depression and anxiety in women with early breast cancer: Five-year observational cohort data. BMJ 330:702-705, 2005 3. Glanz K, Lerman C: Psychosocial impact of breast cancer: A critical review. Ann Behav Med 14:204-210, 1992 4. Eakes G: Chronic sorrow: A response to living with cancer. Oncol Nurs Forum 20:1327-1334, 1993[Medline] 5. Stevinson C, Lawlor DA, Fox KR: Exercise interventions for cancer patients: Systematic review of controlled clinical trials. Cancer Causes Control 15:1035-1056, 2004[CrossRef][Medline] 6. Knols R, Aaronson NA, Uebelhart D, et al: Physical exercise in cancer patients during and after medical treatment: A systematic review of randomized and controlled clinical trials. J Clin Oncol 23:3830-3842, 2005 7. Galvão D, Newton RU: Review of exercise intervention studies in cancer patients. J Clin Oncol 23:899-909, 2005 8. McNeely ML, Campbell KL, Rowe, et al: Effects of exercise on breast cancer patients and survivors: A systematic review and meta-analysis. CMAJ 175:34-41, 2006 9. Courneya KS, Friedenreich CM, Quinney HA, et al: The group psychotherapy and home-based physical exercise (group hope) trial in cancer survivors: Physical fitness and quality of life outcomes. Psychooncology 12:357-374, 2003[CrossRef][Medline] 10. Segal R, Evans, W Johnson D, et al: Structured exercise improves physical functioning in women with stages I and II breast cancer: Results of a randomized controlled trial. J Clin Oncol 19:657-665, 2001 11. Mock V, Frangakis C, Davidson NE, et al: Exercise manages fatigue during breast cancer treatment: A randomised controlled trial. Psychooncology 14:464-477, 2005[CrossRef][Medline] 12. Demark-Wahnefried W, Clipp EC, Morey MC, et al: Lifestyle intervention development study to improve physical function in older adults with cancer: Outcomes from project LEAD. J Clin Oncol 24:3465-3473, 2006 13. Daley AJ, Mutrie N, Crank H, et al: Exercise therapy in women who have had breast cancer: Design of the Sheffield women's exercise and well-being project. Health Educ Res 19:686-697, 2004 14. Thomas S, Reading J, Shephard RJ: Revision of the physical activity readiness questionnaire (PAR-Q). Can J Sport Sci 17:338-345, 1992[Medline] 15. Courneya K, Mackey JR, Jones LW: Coping with cancer: Can exercise help. Physician Sports Med 28:49-73, 2000 16. Borg G: Simple rating methods for estimation of perceived exertion, in Borg G (ed): Physical Work and Effort. New York, NY, Pergamon Press, 1997 17. Prochaska JO, Diclemente C: Stages and processes of self-change of smoking: Towards an integrative model of change. J Consult Clin Psychol 51:390-395, 1983[CrossRef][Medline] 18. Cella DF, Tulsky DS, Gray G, et al: The Functional Assessment of Cancer Therapy scale: Development and validation of the general measure. J Clin Oncol 11:570-579, 1993 19. Piper BF, Dibble SL, Dodd MJ, et al: The revised Piper Fatigue Scale: Psychometric evaluation in women with breast cancer. Oncol Nurs Forum 25:677-684, 1998[Medline] 20. Diener E, Emmons RA, Larsen RJ, et al: The satisfaction with life scale. J Pers Assess 49:71-75, 1985[CrossRef][Medline] 21. Beck AT, Steer RA, Brown GK: Beck Depression Inventory Manual. San Antonio, TX, The Psychological Corp, 1996 22. Fox KR, Corbin CB: The physical self-perception profile: Development and preliminary validation. J Sport Exerc Psychol 11:408-430, 1989 23. Gionet NJ, Godin G: Self-reported exercise behaviour of employees: A validity study. J Occup Med 31:969-973, 1989[CrossRef][Medline] 24. Marcus BH, Simkin LR: The stages of exercise behaviour. J Sports Med Phys Fitness 33:83-88, 1993[Medline] 25. Ebbeling CA, Ward A, Puleo, et al: Development of a single-stage submaximal treadmill walking test. Med Sci Sport Exerc 1991;23:966-973 26. Office of the Deputy Prime Minister (OPDM): The English Indices of Deprivation 2004: Summary (revised). www.communities.gov.uk/pub/443/Indicesofdeprivation2004summaryrevisedPDF154Kb_id1128443.pdf 27. Campbell A, Mutrie N, Whyte F, et al: A pilot study of a supervised group exercise programme as a rehabilitation treatment for women with breast cancer receiving adjuvant treatment. Eur J Oncol Nurs 9:56-63, 2005[CrossRef][Medline] 28. Daley AJ, Crank H, Mutrie N, et al: Patient recruitment into a randomised controlled trial of supervised exercise therapy in sedentary women treated for breast cancer. Contemp Clin Trials (in press) 29. Eton DT, Cella D, Yost KJ, et al: A combination of distribution- and anchor-based approaches determined minimally important differences (MIDs) for four endpoints in a breast cancer scale. J Clin Epidemiol 57:898-910, 2004[CrossRef][Medline] 30. Koinberg I, Langgius-Eklof, Holmberg L: The usefulness of a multidisciplinary education programme after breast cancer surgery: A prospective and comparative study. Eur J Oncol Nurs 10:273-282, 2006[CrossRef][Medline] 31. Lepore SJ, Coyne JC: Psychosocial interventions for distress in cancer patients: A review of reviews. Ann Behav Med 32:85-92, 2006[CrossRef][Medline] 32. Coyne JC, Lepore SJ, Palmer SC: Efficacy of psychosocial interventions in cancer care: Evidence is weaker than it first looks. Ann Behav Med 32:104-110, 2006[CrossRef][Medline] 33. Lemieux J, Topp A, Chappell H, et al: Economic analysis of psychosocial group therapy in women with metastatic breast cancer. Breast Cancer Res Treat 100:183-190, 2006[CrossRef][Medline] 34. Holmes MD, Chen WY, Feskanich D, et al: Physical activity and survival after breast cancer diagnosis. JAMA 293:2479-2486, 2005 35. Cella DF, Tulsky DS: Measuring quality of life today: Methodological aspects. Oncology 4:29-38, 1990[Medline] 36. Demark-Wahnefried W, Aziz NM, Rowland JH, et al: Riding the crest of the teachable moment: Promoting long-term health after the diagnosis of cancer. J Clin Oncol 23:5814-5830, 2005 37. Culos-Reed SN, Carlson LE, Daroux LM, et al: A pilot study of yoga for breast cancer survivors: Physical and psychological benefits. Psychooncology 15:891-897, 2006[CrossRef][Medline] 38. Mustian KM, Katula JA, Gill DL, et al: Tai chi chuan, health-related quality of life and self-esteem: A randomised trial with breast cancer survivors. Support Care Cancer 12:871-876, 2004[CrossRef][Medline] 39. Schmitz KH, Ahmed R, Hannan P, et al: Safety and efficacy of weight training in recent breast cancer survivors to alter body composition, insulin and insulin-like growth factor axis proteins. Cancer Epidemiol Biomarkers Prev 14:1672-1680, 2005 Submitted October 24, 2006; accepted February 12, 2007.
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Copyright © 2007 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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