Trial of Combined Aerobic and Resistance Exercise in Breast Cancer Survivors

Overview

Endurance exercise such as walking has been shown to help breast cancer survivors maintain their energy and quality of life while they are receiving chemotherapy, but there have not been any studies on weight training. In this study, the researchers want to determine if a combined program of endurance and weight training exercises is better than a standard amount of endurance exercise or even a higher amount of endurance exercise in breast cancer survivors receiving chemotherapy. The study will be an experimental design in which the researchers have breast cancer survivors participate in one of the three different exercise programs. The researchers' main interest is in patient rated physical functioning and quality of life, which they will measure before and after the exercise programs by asking participants how they feel on various rating scales. The researchers will also measure their aerobic fitness on a treadmill and how strong they are by having them lift weights.

BACKGROUND: Aerobic exercise has been shown to improve physical fitness and quality of life (QoL) in breast cancer survivors receiving chemotherapy but no study to date has examined the addition of resistance exercise to aerobic exercise in this population. Resistance exercise has proven to be an important adjunct to aerobic exercise in the cardiac rehabilitation population although few trials have controlled for the total volume of exercise. PURPOSE: The primary purpose of the present trial is to compare the effects of a combined aerobic and resistance exercise program (COMB) to a standard moderate volume of aerobic exercise (STAN) and a higher volume of aerobic exercise (HIGH) that controls for the total volume of exercise in the COMB arm. METHODS: The study will be a prospective, three-armed, randomized controlled trial conducted in Edmonton (coordinating center), Ottawa, and Vancouver. Participants will be 300 breast cancer survivors scheduled to receive adjuvant chemotherapy. All three exercise groups will be asked to perform supervised exercise 3 days/week for the length of their chemotherapy treatment. The STAN group will be asked to perform approximately 500 kilocalories/week of self-selected aerobic activities (e.g., treadmill, cycle ergometer, elliptical). This arm of the trial is considered standard care based on the emerging consensus of recent systematic reviews and recommendations from major cancer agencies. The HIGH group will be asked to complete approximately 1,000 kilocalories/week of self-selected aerobic activities. The COMB group will be asked to complete 1,000 kilocalories/week split equally between aerobic and resistance exercise. The primary endpoint in the trial will be change in physical functioning between baseline and post intervention as assessed by the physical functioning subscale of the Short Form (SF) 36 scale. Secondary endpoints will include cardiorespiratory fitness (maximal treadmill test), muscular strength (8 repetition maximum tests), muscular endurance (standard load test at 50% of estimated baseline maximum), body composition (DEXA scans), psychological distress, sleep quality, exercise adherence, and chemotherapy completion rates. RELEVANCE: An important issue for breast cancer survivors receiving chemotherapy is whether there is any advantage to increasing the volume of aerobic exercise or adding resistance exercise to a standard aerobic exercise program. If there is an advantage, then it is important that breast cancer survivors receive this optimal exercise prescription to maximize their ability to cope with their chemotherapy treatments and maintain their physical function and QoL during this difficult time.