|Year : 2014 | Volume
| Issue : 3 | Page : 658-664
The effect of aerobic exercise on quality of life among breast cancer survivors: A randomized controlled trial
Ardiana Murtezani1, Zana Ibraimi2, Aurora Bakalli3, Shaip Krasniqi4, Emine Devolli Disha5, Ilir Kurtishi5
1 Department of Physical and Rehabilitation Medicine, University Clinical Center of Kosovo, Kosovo
2 Department of Pharmacy, University of Prishtina Kosovo, Kosovo
3 Clinic of Internal Medicine, University Clinical Center of Kosovo, Kosovo
4 Department of Pharmacology, University of Kosovo, Pristina, Kosovo
5 Institute of Oncology, University Clinical Center of Kosovo, Kosovo
|Date of Web Publication||14-Oct-2014|
RRESpitalitPN, Prishtina - 10000
Source of Support: None, Conflict of Interest: None
Objective: To determine the effect of moderate-intensity aerobic exercise on the quality of life (QOL) and physical functioning in breast cancer survivors.
Materials and Methods: We randomly assigned 62 breast cancer survivors to an exercise (N = 30) or control group (N = 32). The exercise group trained at a moderate intensity progressing from 25 to 40 min over a 10-week period. The control group did not train. Outcomes were assessed at baseline and postintervention. The primary outcomes were overall QOL - as assessed by the functional assessment of cancer therapy-breast (FACT-B) scale. Secondary outcomes were changes in various subscales of overall QOL, and changes in body composition outcomes: body weight, body mass index, and changes in performance in a 12 min walk test (12MWT).
Results: Sixty-two of 73 women randomized (84.9%) completed the study. There were no significant differences amongst the two groups at baseline for any variable. In the exercise group significant improvements were demonstrated for the FACT-B (13.4 points, P < 0.003), functional assessment of cancer therapy-general (FACT-G) (9.16 points, P < 0.008), the functional well-being subscale (P < 0.010), and the emotional well-being subscale (P < 0.035) compared to the control group. No significant changes in body weight or BMI were observed. Exercise group showed a significant increase in 12MWT (P < 0.009).
Conclusion: We conclude that 10 week of moderate-intensity aerobic exercise program significantly improves QOL and physical functioning in breast cancer survivors. Future studies are needed to evaluate the effectiveness of similar exercise programs over longer periods of time and involving a greater number of breast cancer survivors.
Keywords: Aerobics, breast cancer survivors, exercise, quality of life
|How to cite this article:|
Murtezani A, Ibraimi Z, Bakalli A, Krasniqi S, Disha ED, Kurtishi I.
The effect of aerobic exercise on quality of life among breast cancer survivors: A randomized controlled trial. J Can Res Ther 2014;10:658-64
|How to cite this URL:|
Murtezani A, Ibraimi Z, Bakalli A, Krasniqi S, Disha ED, Kurtishi I.
The effect of aerobic exercise on quality of life among breast cancer survivors: A randomized controlled trial. J Can Res Ther [serial online] 2014 [cited 2020 Aug 11];10:658-64. Available from: http://www.cancerjournal.net/text.asp?2014/10/3/658/137985
| > Introduction|| |
Breast cancer is the most frequent-occurring cancer among women.  Fortunately, early detection, effective treatment, and modification of risk factors have increased survival rates due to breast cancer in recent years. ,, Nevertheless, breast cancer treatments still have side effects that may negatively impact recovery and quality of life (QOL) after initial treatments. 
QOL issues for breast cancer patients include factors such as pain, fear of recurrence, fatigue,  altered sense of femininity, feelings of decreased attractiveness,  anxiety,  and problems associated with treatment-related arm swelling. 
Exercise is an effective intervention to improve QOL, ,, fitness, and physical functioning, ,, as well as to reduce fatigue, , and decrease sleep disturbances  in breast cancer patients and survivors.
Aerobic training has been reported to be of benefit in the treatment of many disorders, including those related to the breast cancer.  Several studies ,,, demonstrate the benefits of exercise for improving the patient's functional and psychological status after breast cancer. Friedenreich and Courneya  concluded that exercise seems to improve breast cancer patients' physiologic and psychologic well-being. Young-McCaughan and Sexton  found that patients with breast cancer who exercised had significantly higher QOL ratings than those who did not exercise. According to Physical Activity Guidelines Advisory Committee Report  there is a strong evidence for an association between improved QOL and physical fitness in breast cancer survivors. Women who maintained their exercise behavior during and after treatment reported a higher QOL 1 to 2 years. 
In this study, we aimed to determine the effects of moderate-intensity aerobic exercise on QOL and physical functioning in breast cancer survivors who have completed surgery, radiotherapy, and/or chemotherapy with or without current hormone therapy use. We tested the hypotheses that 10 weeks of supervised group exercise would improve QOL and physical functioning.
| > Materials and methods|| |
We performed a prospective, randomized controlled trial of breast cancer survivors.
Two hundred and forty-one breast cancer survivors from Oncologic Institute were recruited to the trial. Eligibility criteria included histologically confirmed early-stage breast cancer with no evidence of recurrent or progressive disease, completed surgery, radiotherapy, and/or chemotherapy with or without current hormone therapy use. Eligible participants were not admitted if they had known cardiac disease, uncontrolled hypertension, thyroid disease, respiratory disease, diabetes, mental illness, infection, immune, or endocrine abnormality.
Participants who had fulfilled the eligibility criteria were randomized to either the exercise group (n = 30) or control group (n = 32). All participants signed and received a copy of the informed consent form followed with the completion of the foreseen procedures.
The trial was conducted at the Clinic of the Physical and Rehabilitation Medicine of the University Clinical Center of Kosovo The study was approved by the Ethical Board of the Faculty of Medicine, University of Prishtina .
Random assignment to treatment
Women who had consented to participate were randomly allocated in accordance with recognized procedures, by computer-generated random allocation sequences that were prepared centrally by the trial statistician. The assessor was blinded with regard to the allocation of participants into the treatment groups.
Women assigned to the intervention group attended a supervised group exercise program, three times per week for 10 weeks. The exercise program was divided into a warm-up period, followed by moderate intensity of aerobic exercises, and finishing with a cool-down period.
Warm-up period consisted of 5 min of cycling. The core portion consisted of aerobic exercise program that was performed on treadmills, stationary bicycles, and stair-climbing machines. The duration of aerobic exercise was initially 15 min and was divided equally among the three exercise modalities (treadmills, stationary bicycles, and stair-climbing machines). Sessions ended with 5 min of cool down exercises consisting of slow walking. Following standard guidelines for exercise prescriptions  warm-up and cool-down period remain the same for 10 weeks, until the aerobic exercise period was increased by 2, 2 min a week, such that it was 35 min during week 10.
The participants exercise intensity has been prescribed based on the Karvonen formula.  We used heart rate reserve (HRR) to calculate training zones based on both maximum and resting heart rate, using a range of 50-75%. The maximum heart rate (HR max ) was calculated using the formula: HR max = 220 - Age. The heart rate was monitored by the participants and the supervisor during exercise using Polar FT4 Heart rate monitor.
During the 10 weeks exercise program, exercise intensity was increased from 50% to 75% HRR and exercise duration was increased from 25-45 min per session both in almost linear fashion.
Women in the control group were told to maintain their sedentary lifestyle for 10 weeks.
The primary outcome measure was overall QOL, as measured by the Functional Assessment of Cancer Therapy-Breast (FACT-B) scale.  The FACT-B contains specific subscales assessing physical well being (seven items), emotional well being (six items), social well being (six items), functional well being (seven items), that comprise Functional Assessment of Cancer Therapy -General (FACT-G) (26 items) scale and breast cancer subscale (nine items). The five subscales were summed to obtain the FACT-B score (all 35 items).
Secondary outcomes were changes in various subscales of overall QOL, changes in body composition outcomes, body weight, and BMI, and changes in performance in a 12 min walk test.
Body weight and height were measured on a calibrated scale. Body mass index was calculated as weight in kilograms divided by height in meters squared.
Walking endurance was measured with the 12-min Walk Test (12MWT). It is a functional walking test in which the distance that a participant can walk within 12 min is evaluated. 
Outcomes were assessed at baseline and postintervention.
Self-administered survey was completed by 241 survivors of breast cancer. The survey contained questions on demographic and medical variables. Demographic data (name, age, weight, height, and education level) were collected by self-report. Medical data (the number of days since the diagnosis and the end of treatments, cancer stage, medication, affected lymph nodes, type of treatment, and type of surgery) were collected from medical records.
The data were analyzed on per protocol analysis. STATA Version 11 was used to analyze the collected data. Baseline characteristics of the two treatment groups were tested using independent-sample t-tests for continuous data and Pearson's χ2 for categorical variables. The focus of the analysis was put on using independent-sample t-tests to test whether significant differences existed between the exercise group and control group in all outcomes from baseline to the end of the 10 week intervention period. A P value of less than 0.05 was used as the criterion for statistically significant results.
The data analyses included only those participants who had completed the 10-week interventional period.
| > Results|| |
A total of 241 breast cancer survivors were assessed for eligibility during the recruitment period, and 73 (30.2%) were randomly assigned to the exercise (n = 37) or control group (n = 36). During the intervention period, seven participants (9.5%) from the exercise group dropped out (three due to difficulties in transportation, one due to low back pain, and three due tolymphedema,) compared with four participants (5.4%) in the control group (one due to gynecologic problems, one for personal reasons, and two were unreachable). Overall, 62 of 73 participants completed the trial (84.9%). [Figure 1] shows the flow of participants through the trial.
[Table 1] describes demographic and medical characteristics of the 62 participants who completed the study. Overall, the two groups were similar at baseline. No significant differences were found between the groups on age, weight, BMI, time postcancer treatment, or cancer stage. Participants mean age was approximately 52 years of age. The majority of the participants had completed a college education. The majority of the participants had been diagnosed with stage I or II breast cancer, and the mean time since surgery was approximately 19 months. The largest part of the participants underwent mastectomies (94%), followed by radiation therapy in 60% of cases, and chemotherapy 58% of cases. Most of the women (55%) were taking Tamoxifen throughout the study.
The outcomes of QOL measures are listed in [Table 2]. The baseline values for the overall QOL measures were not different between the groups (P = 0.43). The table summarizes the outcome variables measured at the baseline, and 10 week postintervention assessment, for the intervention and control group separately. Overall QOL, FACT-B, increased 13.4 for the intervention group and decreased -0.81 for controls (P < 0.003). Additional analysis of the pretest to post-test indicated a significant improvement for FACT-G (P < 0.008), functional well being (P < 0.010) and emotional well being (P < 0.035) in the intervention group.
On the other hand, at the 10-week follow-up point, the control group showed no significant improvements regarding the QOL outcomes [Table 2].
[Table 3] presents the body composition and aerobic capacity outcomes that include variables of weight, BMI and 12 MWT. There were no significant differences between the two groups in the baseline values for body weight, body mass index, and 12 MWT. We did not observe any significant difference between groups for changes in body weight and BMI at the 10-week follow-up, except in 12 MWT that increased by 75.5 m in the exercise group, and by 9.1 m in the control group (P < 0.009).
|Table 3: Effect of exercise training on body composition and aerobics capacity outcomes|
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| > Discussion|| |
The results confirmed the hypothesis that 10 week of moderate-intensity aerobic exercise program significantly improves the overall QOL and physical functioning in breast cancer survivors. Our results confirmed previous published evidence ,,,,,, for the efficacy of the aerobic exercise in improving the overall QOL and psychological distress.
In our study with the exercise group, after 10 weeks, we have distinguished significant improvement on FACT-B in comparison with basic values (change of 13 points, P < 0.003), FACT-G (change of 9 points, P < 0.008), functional well-being (change of more than 1 point, P < 0.010), and emotional well-being (change of 2 points, P < 0.035). These results are also supported by studies ,,, on similar exercise program displaying significantly higher levels of physical functioning as well as reporting higher QOL scores than the controls.
This study adds to these prior studies, in which it provides evidence that aerobic exercise may improve QOL in breast cancer survivors, reducing anxiety and increasing energy, counteracting some of the negative consequences of cancer treatment and recovery. The participants that have improved their aerobic capacity and flexibility felt more self-efficient and enhanced their QOL. , Our results support this conclusion.
The majority of the exercise interventions undertaken with this population have focused on aerobic training ,,,,,,, with few studies focusing on the combination of aerobic and resistance exercises. ,,, Therefore, little is known as to the effect of resistance training being a primary exercise choice. Research should be done to determine whether there are differential functional and psychological effects to be achieved among this population by changing the exercise parameters (frequency, intensity, time, and type).
Another appealing finding in this study is that neither of the treatment groups experienced significant changes in BMI or body weight. Our conclusion is consistent with the findings of several other authors. ,, Holmes et al.  studied 51 breast cancer survivors participating in a 16-week mixed strength and endurance training intervention. Although they reported no significant changes in weight or BMI over the course of the 16-week study period, they found significant decrease in hip measurements in the exercise group, suggesting a decrease in fat stores. In our study, if we have implemented more strenuous exercise program longer than 10 weeks, consecutively significant results would be achieved. In addition we have not recorded details about the nutrition during the intervention period; it can affect the results of BMI.
A 12MWT was used to assess physical function in our study groups. Results showed that subjects undertaking the exercise program improved significantly more in walking distance, compared with controls. The finding was in agreement with other researches. ,,, Schwartz et al.  reported that subjects who underwent the exercise program demonstrated greater response in the physical performance assessment (12MWT), compared with subjects who did not adopt the training program (P < 0.05)  Furthermore, several studies ,, involving breast cancer survivors showed statistically significant improvements on cardio-respiratory function tests ranging from a 6-min walk test to maximal treadmill or cycle ergo-meter tests.
Among the strengths of this study is the randomized controlled design. According to participants' characteristics at baseline, our participants were similar and corresponded to those of similar studies. ,,, The exercise regimen was well tolerated by the participants, and exercise adherence was excellent (84.9%). The dropout rate from the trial was 15%, which is similar to other studies on exercise in cancer. , Three participants who developed lymphedema, a possible complication after axillary node resection,  had locoregional radiotherapy that included axillary irradiation, which is a risk factor for lymphedema. 
Limitations of this study warrant discussion. This study utilized a small sample. Long-term outcomes were not performed. Also, a limitation includes a 15% recruitment rate that may restrict the generalizability of our findings. A further limitation is the lack of measures of lean body mass, in order to have more detailed results about changes in body composition. Furthermore, we used only 12MWT to assess physical function. Larger trials that examine the long-term benefits of exercise are needed for this patient group.
| > Conclusion|| |
We conclude that a 10-week moderate-intensity of aerobic exercise showed increased QOL and physical functioning in breast cancer survivors. Future studies are needed to evaluate the effectiveness of similar exercise programs over longer periods of time and involving a greater number of breast cancer survivors.
Authors would like to thank GEN Daniel J. Dire (MC, US Army Res) for providing helpful suggestions and reviewing of this manuscript.
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[Table 1], [Table 2], [Table 3]