Effects of Combined Training on Quality of Life, Neuromuscular and Cardiorespiratory Parameters in Patients Who Have Completed the Primary Treatment for Breast Cancer: a Randomized Clinical Trial

According to the World Health Organization, breast cancer is the most common one among women, both in developed and developing countries. It accounts for 23% of all breast cancer cases worldwide whereas, in Brazil, it represents 25% of new cases per year. However, its mortality rate has increasingly decreased due to advances in screening protocols, diagnoses and treatment in the last decades. Even so, breast cancer and its treatment might cause psychological and physiological side effects that can affect patients' quality of life.

There is evidence that increase in physical activity generates important physical and psychological benefits to patients with cancer. Studies with breast cancer survivors have shown that the fact that the patients become physically active after the diagnosis leads to a 24-67% decrease in total death risk and 50-53% decrease in death related to breast cancer, by comparison with sedentary patients.

Reviews, systematic reviews and metaanalysis of studies that investigated the effects of interventions with physical exercise programs on health outcomes in breast cancer survivors showed the benefits brought to these patients by exercise. However, these reviews have also called the attention of the scientific community regarding the need to standardize measures of outcomes and intervention methods of evaluation since variations found in the studies make it difficult to reach definite conclusions. Furthermore, type, frequency, intensity and duration of exercise sessions to reach beneficial effects on important health parameters for breast cancer have not been well established yet. Therefore, this study aims at analyzing the effects of combined training program (resistance and aerobics), in comparison with a non-training group, on quality of life, as well as on neuromuscular and cardiorespiratory parameters in breast cancer patients in stages one to three who have finished their treatment, such as surgery, chemotherapy and radiotherapy.

Methodology: This trail will be carried out with women with histological confirmed breast cancer who have already completed the primary treatment for breast cancer (including surgery, radiation therapy and chemotherapy) from 6 months to 5 years but keep on hormone therapy. After baseline assessments, the eligible participants will be randomized to the combined exercise group or control non-exercising group. The combined exercise group will follow an eight week exercising program, which consists of three weekly exercise sessions. Each session will last around 60 minutes and will include strength training (with machines and elastic bands) and aerobic exercises on treadmills. Workouts will be guided and supervised by previously trained physical education professionals and physiotherapists. The strength training will comprise nine exercises, which will alternate body segments with maximum repetitions in the first set and the inferior limit of repetitions in the second set. Along the training, the number of series will increase whereas the number of repetitions will decrease. The intensity of the aerobic exercises will be based on the percentage of cardiac frequency of anaerobic threshold. All exercise sessions will take place at the Physical Education School at the Pelotas Federal University, located in Pelotas, Rio Grande do Sul, Brazil.