Exercise has strongest effect on reducing risk of breast cancer returning
For women who have had breast cancer and are looking for the best lifestyle defense on preventing a recurrence, becoming more physically active is their answer.  It’s time to lace up those exercise shoes and get moving. 

This is the advice given by Canadian researchers who looked at various lifestyle changes a woman can make to help reduce the risk of breast cancer returning.  There is a lot of conflicting advice making it hard for women to know which one is definitively the best. 

This study which came out in early 2017, was a review of systematic reviews which aimed to summarize the role of lifestyle factors in the prognosis of women who have had breast cancer.  More than 90% of women with breast cancer are diagnosed at an early stage of the disease but about 25% will eventually die of the cancer primarily because of it having metastasized.  Women who have been diagnosed with the disease want to know what lifestyle changes they can do to reduce the risk of recurrence.  When woman are armed with the knowledge of how to protect themselves from it returning, it can be psychologically beneficial by making them feel more empowered and less out of control.

What evidence on physical activity was found?

The researchers found the following information that pointed to exercise as the primary driver of reducing breast cancer recurrence:

·      A meta-analysis of 22 cohort studies found that physical activity can reduce the risk of death caused by breast cancer by around 40%.  This was the biggest effect of any lifestyle factor on breast cancer outcomes.

·      At least 150 minutes per week of physical activity is recommended.

The main evidence showing why getting physical for women after breast cancer is so important is that when a woman is physically active, it does the following:

·      Lowers endogenous levels

·      Reduces inflammation

·      Reverses insulin resistance

Women are encouraged to engage in at least 30 minutes of moderate-intensity physical activity at least five days of the week, or 75 minutes of more vigorous exercise, along with two to three weekly strength training sessions, including exercises for major muscle groups.  This same advice is also endorsed by the American Cancer Society.

What other important findings did the study show?

Besides the fact that having a regular, consistent exercise regimen is crucial for reducing the risk of breast cancer return, other relevant findings from the study include the following:

·      Weight gain during or after breast cancer treatment increases the risk of recurrence and reduces survival, irrespective of baseline body mass index.

·      Patients who are obese or overweight at breast cancer diagnosis have a poorer outcome.  Although it is possible for such patients to attain meaningful weight loss, there are few data on which this improves breast cancer outcomes.

·      Western-style diets – high in processed grains, processed meats and red meat – and prudent diets high in fruits, vegetables, whole grains, and chicken, have similar rates of breast cancer recurrence.

·      Dietary saturated fat, especially from high-fat dairy products, may be associated with increased breast cancer mortality.

·      Soy products have not been found to increase breast cancer recurrence and may actually reduce it.

·      Recent evidence has shown a strong association between a history of smoking and breast cancer mortality.

·      Findings are too inconsistent to conclude that alcohol consumption affects breast cancer outcomes.  However, limiting alcohol consumption to one or fewer drinks per day reduces the risk of a second primary breast cancer.

·      Supplementation with vitamin C or vitamin E does not have a strong association with reducing breast cancer recurrence.

·      Low levels of serum 250hydroxyvitamin D at diagnosis have been associated with an increased risk of breast cancer mortality.  However, randomized trials are needed to determine whether supplementation improves prognosis.