Many studies have found a link between regular exercise and a lower risk of being diagnosed with breast cancer or breast cancer coming back (recurrence). As a result, the American Cancer Society and many doctors recommend that women who’ve been diagnosed with breast cancer, as well as those who haven’t, exercise regularly -- about 4 to 5 hours per week at a moderate intensity level. (Brisk walking is considered moderate intensity exercise.) This is about double what the U.S. Department of Health and Human Services recommends per week for adults.
At the same time, much research has shown that being overweight increases the risk of breast and other cancers, as well as increasing the risk of recurrence.
A review study suggests that exercising regularly and maintaining a healthy weight are the two most important lifestyle choices a woman diagnosed with breast cancer can make to reduce her risk of recurrence.
The research was published in the Feb. 21, 2017 issue of the Canadian Medical Association Journal. Read “Lifestyle modifications for patients with breast cancer to improve prognosis and optimize overall health.”
A review study is a study that analyzes results from previously published research. In this case, the researchers looked at 67 studies on lifestyle factors and breast cancer recurrence that were published in the last 10 years. Lifestyle factors studied included:
The researchers summarized their results in six main points:
- Exercise: Women who’ve been diagnosed with breast cancer should exercise moderately at least 30 minutes per day, 5 days a week, or do 75 minutes of vigorous exercise per week. Women should also do two to three sessions of strength training for large muscle groups (glutes, back, chest, and hamstrings) per week.
- Avoid weight gain: Weight gain during or after breast cancer treatment is linked to worse outcomes. Women who are overweight or obese at diagnosis also have poorer outcomes.
- Stop smoking: While it’s unclear if stopping smoking after a breast cancer diagnosis affects the risk of recurrence, smoking causes a number of other health problems.
- Limit alcohol: Limiting drinking to one or zero alcoholic drinks per day may help reduce the risk of recurrence.
- Vitamin supplementation: Moderate consumption of vitamin C may be helpful, although more research is needed. Vitamin D supplements can help maintain bone strength.
- Diet: No specific type of diet has been shown to reduce the risk of breast cancer recurrence. Research suggests that patients do not need to avoid soy, and that soy products may help women maintain a healthy weight if they’re used to replace higher-calorie meat protein.
Overall, the researchers found that exercise had the most potential to reduce the risk of recurrence and improve survival -- exercise reduced the risk of dying from breast cancer by about 40%.
"Following the recommended 150 minutes of moderate to vigorous exercise or 75 minutes of vigorous exercise per week, along with two to three weekly sessions of strength training, can help reduce the risk of breast cancer recurrence and mortality,” said Dr. Ellen Warner, of Sunnybrook Health Science Centre, one of the study’s authors. “Of all lifestyle factors, physical activity has the most robust effect on breast cancer outcomes.”
If you’re still recovering from breast cancer treatment, along with being busy with work, household chores, and family matters, finding time to exercise almost every day can seem impossible.
It can help to break up your exercise into 20- or 30-minute sessions that add up to about 4 hours per week. Walking is a great way to start. Maybe you walk 30 minutes before going to work and 20 minutes on your lunch break. You can add a few more minutes by parking farther away from your building or taking mass transit. Or you can make plans to walk with a friend after work -- you’re more likely to stick with exercise if someone else is counting on you. Plus, you can socialize at the same time.
Along with a healthy diet and lifestyle choices, regular exercise is one of the best things women can do to keep the risk of recurrence as low as it can be. This study adds to other research suggesting that regular exercise reduces recurrence risk. Regular exercise also helps keep your physical and mental health in top shape. No matter how old you are, it’s never too late or too soon to get moving. And once you do start, keep at it!
Visit the Breastcancer.org Exercise section for tips on exercising safely and how to stick to an exercise routine.