New research recommends physical activity and weight management as key lifestyle choices that can significantly reduce the risk of breast cancer recurrence.
The vast majority of breast cancer cases are diagnosed at an early stage, with very promising survival rates. Over 90 percent of breast cancer patients are at an early stage at the time of diagnosis, and the 10-year survival rate is currently estimated at 83 percent.
However, in some cases, the cancer does recur, either in the same form or more aggressively than the first time. Research suggests that overall, almost 30 percent of women who were diagnosed with breast cancer at an early stage develop metastasis later on.
New research examines some of the lifestyle factors that influence breast cancer recurrence rates.
The research was conducted by Dr. Ellen Warner, of the Sunnybrook Health Sciences Centre in Canada, in collaboration with coauthor Dr. Julia Hamer, and the findings were published in the Canadian Medical Association Journal (CMAJ) .
The study consists of a meta-analysis of 67 articles that examine several lifestyle choices, including exercise, weight management, dietary patterns, smoking, and alcohol consumption. The review investigates the impact of these lifestyle changes on the chances of recurring cancer and summarizes key points.
Exercise, weight management the most important lifestyle changes
While the authors present their key findings as recommendations to patients, they also caution that the findings should not be seen as a panacea for every breast cancer survivor. Some forms of breast cancer are particularly aggressive and may come back despite the most vigorous efforts to make lifestyle changes.
"Patients should not be made to feel that inadequate lifestyle changes have led to recurrence of their cancer," the authors note.
Of all the lifestyle factors reviewed, physical activity and avoiding weight gain seem to have the most beneficial effect on the odds of breast cancer recurrence.
The researchers comment:
"Of all lifestyle factors, physical activity has the most robust effect on breast cancer outcomes. Weight gain of more than 10 percent body weight after a breast cancer diagnosis increases breast cancer mortality and all-cause mortality. However, there are good reasons to discourage even moderate weight gain because of its negative effects on mood and body image."
Women who are overweight or obese seem to have the lowest chances of survival. By contrast, women who exercise moderately - 30 minutes of physical activity every day, 5 days a week, or 75 weekly minutes of intense exercise - significantly reduce their risk of breast cancer recurrence and breast cancer death.
Diet, however, does not seem to have an impact on breast cancer recurrence. No specific diet was shown to reduce the risk, and the authors note soy consumption is not harmful, but quite the opposite - replacing meat protein with soy might help patients avoid weight gain.
The effects of vitamins, alcohol, and quitting smoking
As for vitamin supplementation, the review did not find sufficient evidence to show vitamin C is helpful, although a meta-analysis included in the study revealed a 15 percent reduction in breast cancer mortality for those who took Vitamin C. The authors of the current review recommend clinical trials to confirm these results.
The authors strongly advise against smoking. Even though the review could not establish a clear link between quitting smoking and recurrence rates, they note that the risk of death associated with smoking should be reason enough to quit.
Alcohol consumption - when limited to one or fewer alcoholic drinks per day - may reduce the risk of breast cancer recurrence.
The authors comment on the significance of their findings.
"Making positive lifestyle changes can be psychologically beneficial to patients by empowering them, since the feeling of loss of control is one of the biggest challenges of a cancer diagnosis," they write, adding:
"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."
Finally, the authors stress the importance of conventional anticancer therapy. All of the participants in the studies reviewed benefited from standard cancer treatment, and the authors remind patients that healthful lifestyle changes should not be used to replace standard treatment.