Over 90% of breast cancers are diagnosed at an early stage, which can help deliver a good prognosis. However, cancers can recur, sometimes more aggressively than before. Research suggests that, overall, around 30% of women diagnosed with breast cancer at an early stage develop metastasis later on.
However, an analysis of 67 articles examining the lifestyle factors that influence recurrence conducted by Dr Ellen Warner at the Sunnybrook Health Sciences Centre in Canada, in collaboration with co-author Dr Julia Hamer, found that of all lifestyle factors, physical activity had the most robust effect on breast cancer outcomes.
The researchers found that a weight gain of more than 10% after a diagnosis increased mortality. Women who were obese had the lowest chances of survival, while those who exercised moderately (at least 30 minutes, five days per week, or 75 weekly minutes of intense exercise) significantly reduced their risk of breast cancer recurrence and death.
While the authors presented their key findings as recommendations, they cautioned that the some forms of breast cancer are highly aggressive and can return despite the most vigorous efforts to make lifestyle changes. They wrote, “Because it is common for patients to reduce their level of physical activity after a breast cancer diagnosis, it is important for health care professionals to promote and encourage exercise in this patient population. Simply receiving advice from an oncologist to exercise more has been shown to increase patients’ level of activity.”