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Journal of Clinical Oncology, Vol 23, No 10 (April 1), 2005: pp. 2378-2388 © 2005 American Society of Clinical Oncology. DOI: 10.1200/JCO.2005.04.106 Effectiveness of Physical Activity on Cardiorespiratory Fitness and Health-Related Quality of Life in Young and Middle-Aged Cancer Patients Shortly After ChemotherapyFrom the Department of Psychosocial Oncology and Rehabilitation, The Norwegian Radium Hospital; Department of Statistics, Institute of Basic Medical Sciences, University of Oslo; Norwegian University of Sport and Physical Education; Department of Oncology, Oslo City Hospital, Ullevaal; and Department of Clinical Cancer Research, The Norwegian Radium Hospital, Oslo, Norway Address reprint requests to Lene Thorsen, Department of Psychosocial Oncology and Rehabilitation, The Norwegian Radium Hospital, N-0310 Oslo, Norway; e-mail: lene.thorsen{at}radiumhospitalet.no
PURPOSE: To evaluate the effectiveness of a supervised home-based flexible training program on cardiorespiratory fitness (CRF), mental distress, and health-related quality of life (HRQOL) parameters in young and middle-aged cancer patients shortly after curative chemotherapy. PATIENTS AND METHODS: One hundred eleven patients age 18 to 50 years who had received chemotherapy for lymphomas or breast, gynecologic, or testicular cancer completed the trial. These patients were randomly allocated to either an intervention group (n = 59), which underwent a 14-week training program, or a control group (n = 52) that received standard care. Primary outcome was change in CRF, as determined by Åstrand-Rhyming indirect bicycle ergometer test (maximum oxygen uptake [VO2max]), between baseline (T0) and follow-up (T1). Secondary outcomes were mental distress, as assessed by the Hospital Anxiety and Depression Scale, and HRQOL, as assessed by the European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire. Two-way analysis of covariance was used to analyze changes from T0 to T1. RESULTS: VO2max increased by 6.4 mL/kg–1/min–1 in patients in the intervention group and by 3.1 mL/kg–1/min–1 in patients in the control group (P < .01). The fatigue score decreased by 17.0 points in the control group compared with only 5.8 points in the intervention group (P < .01). There were no intergroup differences in mental distress or HRQOL. CONCLUSION: A supervised, home-based, flexible training program has significant effect on CRF in young and middle-aged cancer patients shortly after curative chemotherapy, but it has no favorable effect on patients' experience of fatigue, mental distress, or HRQOL.
Testicular cancer, breast cancer, gynecologic cancer, and malignant lymphomas are malignancies that frequently are observed among young and middle-aged cancer patients.1 These diagnoses and their treatments commonly lead to reduced physical and mental health status,2-8 which may influence the patients' health-related quality of life (HRQOL) both during and after treatment. 9-12 There has been a growing interest in the association between physical activity and HRQOL in cancer patients, and experimental studies indicate that regular physical training improves HRQOL parameters, such as physical function, mental distress, and fatigue.13-17 Most of these studies have evaluated the effect of structured training interventions, typically including three to five training sessions per week. Training modes, such as treadmill or outdoors walking, are most commonly used, and the training intensity is usually monitored objectively using heart-rate monitors. The advantage of closely structured training programs (efficacy studies) is the high degree of control of exercise frequency, duration, and intensity and, thus, better reproducibility of the intervention and its results. However, such predefined interventions give a limited choice of activity to the individual patient, making the programs potentially less pleasurable, which may contribute to decreasing motivation in some patients. Furthermore, the intervention might be difficult to implement clinically for larger patient groups outside specific studies. In flexible training interventions, the exercise program is adapted more individually, according to the patient's choice of activity, frequency, duration, and intensity of the exercise sessions (effectiveness studies). To date, most randomized studies in the field of physical activity in cancer patients have focused on the effect of exercise on HRQOL parameters during the treatment period.13, 16-23 In two studies, the effects of exercise on HRQOL have been investigated several months after treatment. 14,15 To our knowledge, the effect of physical activity on cardiorespiratory fitness (CRF) and HRQOL in cancer patients shortly after treatment has not been studied previously. The main objective of this prospective, randomized, controlled trial was to evaluate the effect of a supervised, home-based, flexible training program on CRF and HRQOL parameters in young and middle-aged cancer patients shortly after curative chemotherapy and to compare the results with those of a control group. We hypothesized that the intervention would lead to significantly increased CRF, reduced mental distress, and improved HRQOL compared with the control group. Particular attention was placed on fatigue, which was expected to decrease more in the intervention group than among the controls.
Setting and Patients All patients were recruited from two university clinics from Oslo, Norway, the Norwegian Radium Hospital and the Oslo City Hospital (Ullevaal Hospital). Inclusion criteria were primary treatment including chemotherapy for malignant lymphomas and breast, gynecologic, or testicular cancer; discontinuation of treatment approximately 1 month before baseline evaluation; no evidence of disease at the time of intervention; age between 18 and 50 years; and no geographical obstacles for repeated physical tests. Major physical or mental comorbidity represented the principal exclusion criterion, and none of the patients needed special medical care attributable to their recent anticancer treatment. The construction of diagnostic groups was based on the chemotherapy received, which again was associated with the type of malignancy. All breast cancer patients had received either nine cycles of cyclophosphamide, methotrexate, and fluorouracil or six cycles of fluorouracil, epirubicin, and cyclophosphamide, in addition to surgery and radiotherapy. Patients with gynecologic cancer had undergone abdominal surgery, followed by six to nine cycles of carboplatin and paclitaxel. All lymphoma patients had received six or eight cycles doxorubicin, bleomycin, vinblastine, and dacarbazine or cyclophosphamide, doxorubicin, vincristine, and prednisone, which was often supplemented by limited-field radiotherapy at moderate dose (25 to 30 Gy). The patients with testicular cancer had had postorchidectomy chemotherapy (four cycles of bleomycin, etoposide, and cisplatin). In addition, 65% of the testicular cancer patients had undergone retroperitoneal surgery after chemotherapy.
Recruitment and Randomization
Intervention and Control The intensity of the exercise was adjusted according to the patient's subjective experience of tiredness. The patients in the exercise group received a copy of the Borg scale, a numerical scale used to rate perceived exertion. 24 The score range is from 6 to 20, where a value of 6 means no exertion at all and 20 means maximal exertion. The patients were advised to maintain their exercise intensity comparable to a level between 13 and 15 (slightly strenuous to strenuous). All patients were offered a heart-rate recorder. The minority of patients who chose this option were recommended to keep intensity levels at 60% to 70% of maximal heart rate (220 beats per minute [bpm] – age). All patients were contacted every 2 weeks by the instructor for discussion about choice of activity and frequency, duration, and intensity of the training sessions, and adjustments were made if necessary. The control group did not receive a personalized training program. They were told to be as physically active as they would have been if they were not informed about this study.
Outcome Measures HRQOL. The assessment of HRQOL was performed by using the European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire C30 (EORTC QLQ-C30), which is a psychometrically robust instrument designed to be applicable to a broad range of cancer patients. The instrument has been evaluated with regard to both validity and reliability. 27-30 The EORTC QLQ-C30 comprises five functional scales (physical, role, emotional, social, and cognitive), three symptom scales (fatigue, pain, and nausea and vomiting), and six single items assessing additional symptoms commonly reported by cancer patients. It also includes two questions on patients' overall quality of life and overall health condition, providing a global quality-of-life score. In the present study, the dimensions of physical function, emotional function, fatigue, and global quality of life were considered. These scales were transferred to a 0 to 100 scale, which was calculated by using the scoring manual provided by the EORTC.31 For the physical function, emotional function, and global quality-of-life scales, a higher score indicates better level of functioning, whereas increasing values on the fatigue scale indicate more symptoms. Mental distress. Mental distress was assessed by the Hospital Anxiety and Depression Scale (HADS), a self-rating scale developed to screen for levels of anxiety and depression, particularly in somatically ill patients. 32-33 The instrument has been validated against other scales 34 and has been extensively used and proven useful in cancer patients. 35-37 The psychometric and case-finding properties of HADS are considered to be good. 33 HADS consists of 14 items, seven items for anxiety and seven items for depression. Each item is scored from 0 (not present) to 3 (maximally present). The total HADS score ranges from 0 to 21 for each subscale, where 0 means no anxiety or depression symptoms and 21 defines the maximum of mental distress. If less than three responses were missing on each subscale, they were inputted by the individual mean scale value. Activities. For both the intervention and the control group, the patients' adherence to exercise was assessed by a multiple-choice question in the T1 questionnaire. The patients were asked to provide information about the type(s) of activity they had performed, the frequency per week, and the duration of each training session.
Sample Size Calculations and Statistical Analyses
Data were analyzed using the computer-based SPSS 10.0 (SPSS Inc, Chicago, IL). To analyze differences between the completers and the nonparticipants and dropouts, we used two-sample t tests for continuous data and the Pearson's Intergroup differences in score were compared by two-way analysis of covariance (ANCOVA), with group and baseline score included as explanatory variables in the main model. Furthermore, activity before diagnosis, age, sex, diagnosis, and stage of the disease were included one by one as covariates in the analysis. The final model included statistically significant covariates only. To assess potential differences in the effect of the intervention between different subgroups, we also included an interaction term between each significant covariate and group assignment. If no significant interaction was found, the interaction terms were excluded from the models. To assess the sensitivity of the results, we performed corresponding analyses in all randomized patients. In this intent-to-treat (ITT) sample, we imputed outcome measurements based on the last observation carried forward principle (ie, assuming that the T1) measurement was equal to the T0 measurement of each variable of interest).
Patient Compliance A total of 220 patients were invited onto this study, and 62 patients declined to participate (29%; 23 men and 40 women). The most frequently reported reasons for declining were study site too far away from home (n = 13), prefer to manage by themselves or already active (n = 12), not interested (n = 11), too many other things to do (n = 4), did not want to be reminded of illness (n = 4), did not want to commit themselves (n = 3), and other reasons (n = 8). Twenty patients did not provide a reason for their refusal. Nineteen patients first agreed to participate but then refused to continue before the T0 measurement. The remaining 139 patients were randomly allocated to the intervention group (n = 69) or the control group (n = 70). Between T0 and T1, 10 and 18 patients dropped out of the intervention group and control group, respectively. Overall, end-of-trial data were available for 59 patients in the intervention group and 52 patients in the control group (Fig 1).
There were no differences in age and sex between the 111 completers and the 109 nonparticipants and dropouts, but only 13% of the patients with breast cancer refused to participate or dropped out compared with 38% who completed the study (P < .001). Of the patients with gynecologic cancer, 40% refused to participate or dropped out compared with 22% who completed the study ( P < .005; Table 1). The same was true for patients with advanced disease because only 22% of patients with distant disease completed the trial compared with 42% of patients with distant disease who refused to participate or dropped out. When we performed the same analysis on the 111 completers compared with those who dropped out (n = 28), we observed a significant difference in breast cancer only (P < .03; data not shown).
Baseline Characteristics of Intervention and Control Groups There were no differences between the groups in age, sex, days from end of treatment to T0, weeks from T0 to T1, diagnosis, or treatment (Table 2). There were also no significant intergroup baseline differences in body mass index, smoking habits before treatment, physical activity level before and during treatment, mental distress, or HRQOL. However, the intervention group had a lower baseline CRF compared with the controls (28.2 mL O2/kg–1/min–1 v 31.7 mL O2/kg–1/min–1, respectively; Table 2). At T0, no association was observed between VO2max and fatigue in the two groups (data not shown).
Compared with the control group, more patients in the intervention group performed weight training, cycling, and water activities (Table 3). However, the mean number of minutes of exercise per week was the same in the two groups (data not shown). The intervention group performed a larger number of different activities compared with the control group. Mean number of activities performed was 2.6 and 1.9 in the intervention group and the control group, respectively (P = .002; Table 3). Two patients in the intervention group did not adhere to the recommended minimum of two exercise sessions per week compared with 16 patients in the control group (data not shown). There was a dose-response association between number of minutes exercising per week and change in VO2max from T0 to T1 in all patients combined (Fig 2).
Changes in CRF, Mental Distress, and HRQOL VO2max increased by 6.4 mL O2/kg–1/min–1 in the patients in the intervention group and by 3.1 mL O2/kg–1/min–1 in patients in the control group (Table 4). This corresponds to 23% and 10% changes in VO2max from T0 to T1 in the intervention group and control group, respectively (Table 4). Contrary to our hypothesis, the EORTC QLQ fatigue score decreased more in the controls (17.0 points) than in the intervention group (5.8 points). There was no significant association between change in fatigue and improved physical fitness (data not shown). There was no intergroup statistically significant difference in mean scores of reduction for mental distress and EORTC QLQ emotional function between T0 and T1 (data not shown), but the data listed in Table 4 indicate a tendency towards greater reductions in the control group than in the intervention group (Table 4).
ANCOVA showed a significant difference in mean CRF score at T1 between the groups (intervention and control; P < .01) and also when adjusted for CRF at T0 (Table 5). Age had an overall effect in the model on improvement in physical fitness, as demonstrated by ANCOVA (data not shown). However, there was no significant interaction between the two groups and CRF at T0. ANCOVA analyses of other outcome variables showed no significant differences between groups with regard to mean anxiety and depression scores (HADS) or physical function, emotional function, or quality of life (EORTC QLQ). However, patients in the intervention group reported significantly more fatigue compared with patients in the control group (P < .01), even when fatigue at T0 was included in the model.
No difference between groups was observed for changes in body mass index (data not shown). The results from ITT analysis (n = 139) were similar to those reported in the preceding paragraphs, and these analyses, to some extent, ascertained that dropouts during the intervention period had no significant effect on the results reported.
To our knowledge, this is the first study to demonstrate that a supervised, home-based, flexible training program applied shortly after chemotherapy increases CRF in cancer patients. These results are, to some extent, in line with the findings of Courneya et al14 who observed a beneficial effect of a structured training intervention on peak oxygen consumption compared with a control group in breast cancer patients who started the intervention several months after treatment. MacVicar et al20 also showed improved VO2max for a 10-week interval-training cycle ergometer protocol compared with a stretching and flexibility exercise program in breast cancer patients during chemotherapy. Burnham and Wilcox15 observed that their training group, who performed both low- and moderate-intensity exercises, had a positive effect on aerobic capacity several months after treatment compared with the control group. Contrary to these findings, Segal et al 18 did not observe any effect of structured exercise on aerobic fitness in breast cancer patients during treatment. Because the improvement in VO2max in the intervention group exceeded that of the control group, one can speculate whether training programs involving multiple activities are superior to those recommending only one. Another new finding of this trial is the lack of any beneficial effect on mental distress and HRQOL parameters of the supervised intervention shortly after chemotherapy. In fact, it seems that the patients in the control group had a slightly better outcome for these dimensions compared with patients in the intervention group, with significant differences with respect to fatigue. These observations contrast to most comparable studies. Segal et al 13 demonstrated a positive effect of a 12-week supervised strength-training program on fatigue and overall HRQOL in men receiving androgen deprivation therapy for prostate cancer. Dimeo et al 19 observed a positive effect of an interval exercise, using a cycle ergometer in bed, on fatigue and psychological distress in cancer patients during hospitalization, and Courneya et al 14 reported a positive effect on fatigue and overall HRQOL in breast cancer patients several months after treatment. Burnham and Wilcox 15 observed a significantly higher overall HRQOL improvement in the exercise group compared with the control group, but in agreement with our study, they found no difference in mental distress between the groups. Mock et al 17 demonstrated a positive effect of a 6-week individualized self-paced progressive walking program on fatigue and anxiety in breast cancer patients during radiotherapy; however, there were no significant differences between the exercise group and the control group in terms of depression. Segal et al 18 did not find any significant group differences in HRQOL in breast cancer patients during treatment; although, in agreement with our study, the patients in the control group had a slightly better outcome for some HRQOL dimensions than patients in the intervention group. Thus, the magnitude of changes in mental distress, fatigue, and HRQOL parameters in trials in this area are not consistent. It is not clear whether these disparities of outcome are the result of differences in the patient characteristics and/or the type and timing of intervention or whether these variations can be explained by different methods of assessment. Therefore, clinical trials that directly evaluate the optimal type and timing of postchemotherapy exercise interventions for cancer patients are needed, together with methodologic studies that evaluate methods of assessment. Our surprising findings concerning more improvement of fatigue in the control group might be related to the onset of the intervention at a time when the patients have met the requirements of a strict chemotherapy program and when the patients' physical condition was probably at the lowest and postchemotherapy fatigue was at its highest, causing the training intervention to be an additional burden for the patients. Future studies might allow some more time for spontaneous recovery after chemotherapy before intervention is started. More patients in our intervention group performed multiple activities compared with the control group. The performance of multiple supervised activities by itself could represent additional stress for the patients, and different activities often require structured planning of daily life (for example, to make time to get to the gym or swimming hall). These aspects might also have been extraordinarily stressful for the patients in the intervention group and, to some extent, might explaining why fatigue was reduced less in this group than in the control group. Finally, our measure for fatigue from the EORTC QLQ did not differentiate between acute and chronic fatigue. The time frame of last week probably covered short-term fatigue more than long-term fatigue, which is better assessed by other instruments. Knobel et al 38 validated the fatigue scale in EORTC QLQ-C30 against the Fatigue questionnaire, the latter measuring both physical and mental fatigue. The analysis demonstrated that the fatigue scale in EORTC QLQ-C30 correlated higher with the physical fatigue scale (r = 0.67 to 0.75) than with the mental fatigue scale (r = 0.49 to 0.61). They recommended the use of a domain-specific instrument when fatigue was the end point, and such an instrument could have been more suitable in the current study. This study was the first intervention trial of physical activity at our center. We expected that the physical tests and the intervention program would represent an unjustifiable burden for patients above 50 years of age, and that decision explains the young mean age of our sample. Our results might have differed if the mean age had been higher because higher age often is related to lower physical fitness, and in that case, the increase in VO2max would be higher with optimal exercise. However, if the intensity of the exercise program had been too high, these patients might become even more fatigued than those in the existing intervention group. Making a popular and motivating training program suitable for both sexes in various age groups is not easy. Contrary to many other intervention studies of physical activity, we chose a supervised, home-based, flexible training program (effectiveness study) instead of a fully structured training program (efficacy study). By allowing patients to choose activities by themselves, we hoped to increase the inclusion rate, to reduce the dropout rate, and to prolong motivation. In addition, we wanted an intervention design that could be easily implemented in the patients' daily lives. The strengths of this study are the randomized controlled trial design, the use of validated measures of mental distress and HRQOL, a high sample size, and documentation of reasons for noncompliance. Limitations of the study include the use of an indirect VO2max test (Åstrand) and no available information about CRF and mental health among the patients who refused to participate or dropped out. Our findings may have been influenced by the fact that the analysis was based on the final sample available rather than on the original sample randomly assigned to the intervention or control group. Patients in this trial seem to be a selected group because the CRF at T0 was higher and the level of depression was lower than expected compared with published scores from the general population in the same age range and sex distribution. 39,40 Patients with advanced disease and gynecologic cancer more often refused to participate or dropped out of the study, and patients with breast cancer more often completed the trial. We believe that the patients included in this trial probably represent a group of patients with a relatively good physical and psychological functioning under the current circumstances. They were a group of patients motivated for physical activity and physically able to adhere to their program. Because of this selection, extrapolation of our results to cancer patients with poor physical condition and low motivation for physical activity should be performed with caution. We also believe that, if all eligible patients had participated, the mean baseline VO2max would have been lower, and in that case, the increase in VO2max would have been higher with optimal exercise. However, we would have had a group of patients with overall poorer physical condition, and they could have been more fatigued by performing the exercise program compared with the available intervention group if the exercise program was not adjusted appropriately. Despite difficulties with carrying out ITT analysis because the availability of the follow-up data is missing, we have performed ITT analysis by inputting outcome measurements based on the last observation carried forward principle. The ITT results did not differ from the analysis on the final available sample. A supervised, home-based, flexible training program shortly after chemotherapy had beneficial effect on CRF in young and middle-aged cancer patients. However, this favorable effect is not reflected in the patients' scores of fatigue, mental distress, and HRQOL. The reasons for these latter results might be related to the selection of patients, type and timing of the intervention, and the assessments used. These factors need to be explored in future studies.
The authors indicated no potential conflicts of interest.
We thank Inger Sandvik and Randi Bergersen for helpful assistance with performing physical tests and Sports Aerobic Training Center Training Institute for giving patients free entrance to perform strength training and aerobic exercise.
Supported by the Norwegian Foundation for Health and Rehabilitation and The Norwegian Cancer Society. Authors' disclosures of potential conflicts of interest are found at the end of this article.
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Copyright © 2005 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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ABSTRACT
INTRODUCTION
2 mL O2/kg–1/min–1. For the calculation of the necessary sample size, we assumed a standard deviation of 3 mL O2/kg–1/min–1 and required a significance level of 5% and a power of 80%. With these assumptions, each group should comprise at least 37 patients. 
2 test for categoric data. For ordinal variables, the 
