A 12-month supervised exercise program improved cardiovascular function in women receiving adjuvant chemotherapy for breast cancer, including anthracyclines and taxanes. By contrast, cardiovascular function decreased among women with breast cancer who did not exercise according to the program guidelines. These results of a randomized clinical trial were presented at the 2018 San Antonio Breast Cancer Symposium.
Incorporate Supervised Exercise Program
“All subgroups in the exercise intervention group benefitted from physical activity during breast cancer treatment. Our study supports incorporating supervised clinical exercise programs into breast cancer treatment guidelines,” stated lead investigator Inger Thune, MD, PhD, Professor and Senior Consultant in Oncology, Oslo University Hospital, Norway.
“All patients with breast cancer receiving chemotherapy should be offered tailored exercise programs based on assessed pretreatment level of function,” she added.
The success of this program depended partly on the oncologists’ buy-in on the importance of exercise, Dr Thune emphasized. “The treating oncologist encouraged participation in this program and checked up on patients each month to see how they were doing,” she added.
Adherence to the exercise intervention was more than 90%, perhaps because the oncologists supported the program.
“For such a program to be successful, clinicians have to support the importance of exercise. I speak to all my patients about exercise ahead of surgery. So do my colleagues,” Dr Thune suggested. “Patients should know that their cardiovascular function during treatment will affect their physical function later in life. Cardiovascular function is a marker of susceptibility to comorbidity during survivorship.”
Program Details
To enroll in the Energy Balance and Breast Cancer Aspect (EBBA)-II study, the patients were screened and assessed by trained nurses for cardiovascular capacity using maximal oxygen uptake to assess their aerobic capacity as a surrogate marker for cardiovascular function.
The treating physician telephoned patients to invite them to participate in the study, and 545 patients decided to enroll. The participants were aged 18 to 75 years (mean age, 55 years) and had stage I or II ductal carcinoma in situ or lobular carcinoma in situ, had no known severe comorbidity, and were capable of participating in exercise. They also had no history of previous cancer.
Three weeks after surgery, the patients were randomized to the exercise intervention group or to the standard-of-care group. The exercise intervention group entailed a 12-month supervised, group-based program of strength and endurance exercise that was tailored to each patient’s physical capacity.
The participants in the exercise intervention did moderate- to high-intensity stretching and weight-bearing exercises outdoors for 60 minutes twice weekly, as well as 120 minutes of exercise at home, for a total of 240 minutes every week.
The control group received standard of care, with no limit or restrictions on physical activity.
“Exercises were modified according to the patient’s situation,” Dr Thune said. “For example, if you had a mastectomy, you couldn’t do certain stretching exercise during the first few months.”
A total of 55% of patients in each arm received chemotherapy; 53% received anthracycline treatment and 39% received treatment with a taxane. Approximately 58% of the women had received endocrine therapy. There was a slight imbalance between the study arms in terms of radiation treatment: 76.8% of patients in the exercise group versus 84.7% in the control arm received radiation treatment.
Cardiovascular Function
The patients were assessed for cardiovascular function before surgery, as well as at 6 months and 12 months after randomization. The women’s median body mass index was 25.6 kg/m2.
“VO2max [maximal oxygen uptake] was similar and quite high in both groups at baseline,” Dr Thune said.
Among all the study participants, at 12 months the exercise group went back to baseline levels of maximal oxygen uptake, with a 0.3% increase, whereas the controls had an 8.9% decrease.
Among women who did not receive chemotherapy, at 12 months the maximal oxygen uptake increased by 1.6% in the exercise group and decreased by 2.7% in the control group.
In the women who did receive chemotherapy, at 6 months the maximal oxygen uptake decreased by 9% in the exercise group and by 14.3% in the control group. At 12 months, the oxygen uptake increased by 0.8% among patients in the exercise group and decreased by 6.4% among the controls.
A similar pattern in oxygen uptake was observed in patients who received treatment with a taxane at 6 months and 12 months.
Adverse Events
The number of adverse events was “incredibly low,” Dr Thune said. “I was worried that they might faint on the treadmill, but they didn’t.”
“Whether you were treated only with surgery, or you got chemotherapy as well, all patients had a good effect from the intervention,” Dr Thune stated.
Commenting on the positive results of this study, San Antonio Breast Cancer Symposium Co-director C. Kent Osborne, MD, Director, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, said, “I think exercise is extremely important. I encourage all my patients to get exercise. It is also important for the family not to act like the patient is sick, and encourage physical activity. Data show that exercise improves survival.”