Exercise Most Powerful Lifestyle Factor in Improving Breast Cancer Outcomes

A recent literature review examined the body of research on lifestyle changes that can reduce the risk of recurrence or death among women diagnosed with breast cancer. Exercise was found to be the strongest protective factor for both outcomes.

Researchers identified and assessed 67 articles that studied the association between breast cancer recurrence or mortality and a variety of factors, including diet, exercise, weight loss, smoking, alcohol, and vitamin intake. Their findings have been summarized in the Canadian Medical Association Journal.

The most significant factor was physical exercise, which reduced the risk of recurrence as well as mortality. These effects were even stronger for postmenopausal women, women with a body mass index above 25, and women who met the recommended levels of activity as specified by cancer society guidelines. The researchers noted that adherence to these recommendations is generally low, as patients’ physical activity tends to decrease after a breast cancer diagnosis, making the development of initiatives to encourage exercise in this population especially crucial.

Weight gain before and after diagnosis was strongly linked to poorer breast cancer outcomes, both in terms of recurrence and mortality. There were no conclusive findings on whether weight loss could improve these outcomes, but the authors noted that longer-term studies that are currently underway could provide additional insight into these effects.

Smoking was another factor that increased the risk of death from breast cancer, as women who continued to smoke after diagnosis had higher mortality rates than those who had never smoked and, to a lesser extent, women who quit after being diagnosed. Evidence was insufficient to determine that smoking increases the risk of breast cancer recurrence. The effects of alcohol consumption could not be definitively determined; however, as some studies have indicated, a link between alcohol and cancer recurrence, the authors recommended that restricting the consumption of alcohol “is a worthwhile goal to reduce the risk of a second primary breast cancer.”

The body of evidence surrounding diet and vitamin intake did not yield many conclusive findings either. Vitamins C and D as well as soy products could potentially reduce breast cancer recurrence or mortality, but randomized trials are needed to confirm the preliminary findings. There was no association found between breast cancer outcomes and vitamin E intake or a “prudent diet,” defined as a diet high in fruits, vegetables, whole grains, and chicken.

Overall, the researchers concluded that the current literature provides the strongest support for interventions that encourage women to exercise more and quit smoking. They noted that a cancer diagnosis could present an opportunity for a “teachable moment” where a woman might be more strongly motivated to change her lifestyle factors.

Still, the benefits potentially experienced from these lifestyle changes cannot completely counteract the effects of a tumor, and outcomes will be different for every patient. “Patients should not be made to feel that inadequate lifestyle changes have led to recurrence of their cancer,” the authors warned.