Exercise Programs Improve Outcomes for Patients with Breast Cancer

Special attention to reducing the risk of cardiovascular disease should be a priority for long-term care of patients with breast cancer by providing patients with exercise programs, according to Dr. Jean-Bernard Durand.

“The mortality for breast cancer continues to go down, but what women are going to be faced with if they do not have a recurrence (is that) their number one cause of death is cardiovascular disease,” said Durand. “We have to do a much better job of managing their modifiable risk factors and comorbid conditions.”

In a presentation at the 37^th Annual Miami Breast Cancer Conference® Durand described how physical activity and avoidance of weight gain are two important factors in reducing recurrence and mortality in patients with breast cancer. At the time of diagnosis, patients with early breast cancer may already be at a heightened risk of developing cardiovascular disease and further treatment for breast cancer will have side effects on a patient’s cardiovascular health.

Durand, medical director of Cardiomyopathy Services, and director of cardiovascular genetics research and the Cardiology Fellowship Program at The University of Texas MD Anderson Cancer Center, explained how by looking at a patient’s cardiorespiratory fitness physicians could craft a personalized fitness program for patients to curb side effects from their diseae and treatment.

Cardiorespiratory fitness is an index of functional capacity of the heart and lungs and reflects the efficiency of oxygen uptake, transport and utilization in the muscles. “It is an excellent surrogate of exercise dose and a reproducible measurement,” said Durand.

In a study of 248 patients with breast cancer, the prognostic significance of cardiopulmonary function was assessed and measured by peak oxygen consumption. Patients with breast cancer represented 4 cross-sectional cohorts: before, during, after adjuvant therapy for nonmetastatic disease and during therapy in metastatic disease.

Despite normal cardiac function, women with breast cancer demonstrated marked impairments in cardiopulmonary function. Peak oxygen consumption was, on average, 27% less than that of age-matched sedentary in otherwise healthy women without a history of breast cancer. The impairment in peak oxygen consumption during primary adjuvant chemotherapy was 31% less than that of healthy sedentary women and 33% in those patients with metastatic disease.

Improved cardiopulmonary function is also possible with the introduction of exercise training for patients with breast cancer. An analysis of 6 studies involving 571 adult patients with cancer examined the effects of supervised exercise training versus non-exercise on the measurement of peak oxygen consumption.

Intervention lengths were in the range of 8-24 weeks. In all studies, exercise was prescribed 3 times per week and session duration ranged 14 to 45 minutes. Exercise training was associated with a statistically significant increase in peak oxygen consumption, translating to an improvement from baseline to postintervention of 15% favoring exercise.

Durand noted that the MD Anderson Healthy Heart Program takes a multidisciplinary approach to improve patient outcomes. The team includes physicians, exercise physiologists, health educators, dietitians and nurses. The patient undergoes a preliminary evaluation that includes a screening exam and a treadmill test to determine their maximal oxygen consumption.

“This will allow us to assess cardiopulmonary safety and determine the exercise dose, as well as compare their fitness level relative to their age and sex,” he explained. Standard of care assessment is also conducted and includes assessing the impact of prior cancer treatment on heart health, cholesterol levels, risk of hypertension or high blood pressure, risk of diabetes, body weight and waist measurements, family history on heart health and, if needed, smoking cessation.

“One difficulty is trying to explain the metabolic equivalent task [METs] to patients,” Durand noted. “The Harvard School of Public Health does a great job of breaking this down into light, moderate, and vigorous activity. We like to shoot for the [moderate] area of 3 to 6 METs,” he noted.

METs indicates metabolic equivalents and is typically defined as the ratio a person expends energy relative to their mass.

In a separate study highlighted in Durand’s presentation, patients whose exercise program consisted of nine or more MET hours per week was associated with a 23% reduction in the risk of cardiovascular events regardless of age, cardiovascular disease risk factors at diagnosis, menopausal status and type of anticancer therapy.

Patient biases also play into difficulties for prescribing patients to exercise programs. “We have biases and the patient has biases. The patient bias is that you are expecting them to get to a gym, get a personal trainer and do exercise every single day and that could not be farther from the truth,” Durand said. “I like to recommend the buddy program, finding a neighbor or friend who will walk with you at a brisk pace, and set up a schedule that you will do this as a team.”