Lifestyle modifications for patients with breast cancer to improve prognosis and optimize overall health.

CMAJ | FEBRUARY 21, 2017 | VOLUME 189 | ISSUE 7 © 2017 Joule Inc. or its licensors A lthough more than 90% of patients with breast cancer have early stage disease at diagnosis, about 25% will eventually die of distant metastasis.1 Many patients with breast cancer seek information from a variety of sources about behaviours that may reduce their risk of recurrence.2 Making positive lifestyle changes can also be psychologically beneficial to patients by empowering them, since the feeling of loss of control is one of biggest challenges of a cancer diagnosis. In this review, we identify which lifestyle changes can be recommended to patients as an adjunct to standard breast cancer treatments, to reduce their risk of distant recurrence and death. We review the role of lifestyle factors, particularly weight management, exercise, diet, smoking, alcohol intake and vitamin supplementation, on the prognosis of patients with breast cancer. Our literature search is summarized in Box 1. It is challenging to study lifestyle factors independently, because patients who are more physically active often are leaner, eat a healthier diet and are typically less likely to drink excessive amounts of alcohol or smoke; however, many studies try to adjust for these confounders.3 Another limitation is the potential impact of lifestyle factors before diagnosis.4 Regrettably, but understandably, we found very few randomized trials.