Dr. Lena Suhaila
Exercise Reduces Risk of Breast Cancer, but Benefits Disappear if Women Stop Exercising
A study published in the journal Cancer Epidemiology, Biomarkers & Prevention reports that obese women have a 35% higher risk of developing triple-negative breast cancer and a 39% higher risk of estrogen receptor-positive breast cancer. The study also reports that physical inactivity was also associated with a higher chance of developing breast cancer.
Scientists have been aware of an association between obesity and postmenopausal breast cancer risk. The association was thought to exist between adipose tissue and estrogen receptor stimulation. Adipose tissue produces excess estrogen, which can stimulate estrogen receptors on the surface of cancer cells, encouraging growth and proliferation.
This study is pointing out something unique, lack of exercise and physical activity can even increase the risk of triple-negative breast cancers. Triple-negative breast cancer phenotype encompasses a breast tumor subtype that is clinically negative for expression of the estrogen and progesterone receptors and lacks over expression of the HER2 protein. Triple negative breast cancer accounts for between 10 to 20% of all breast cancers and conventionally has treatment poor outcomes because of a lack of a receptor target for conventional drugs to act upon.
Researchers in this study gathered information from 155,723 females who had enrolled in the Women's Health Initiative. Levels of baseline BMI (body mass index) and physical activity among 307 females who have had triple-negative breast cancer, as well as 2,610 who had estrogen receptor-positive breast cancer were assessed. They found that:
Those with the highest BMIs had a 35% higher chance of developing triple negative breast cancer
Those with the highest BMIs had a 39% higher chance of developing estrogen receptor-positive breast cancer
The most physically active women had a 23% lower risk of developing triple negative breast cancer
Those with the highest levels of physical activity has a 15% lower risk of developing estrogen receptor-positive breast cancer
This paper raises questions about the role of growth factors and inflammation. Inflammation plays a role in all chronic disease, including cancer. Inflammation is best mediated through adherence of healthy organic whole foods, plant based diet and exercise.
Two women may be diagnosed with the same type of breast cancer, and yet the disease can act very differently in these two women. This is because breast cancer is not just one disease; it is a complex combination of many diseases. Only 5-10% of breast cancers are genetic, the other 90- 95% can originate from a multifactorial array of causes. It is not as simple as advising a woman to eat right and exercise and she won’t get breast cancer but, lifestyle does play a huge role in both development of breast cancer and the outcome if a woman does develop breast cancer.
What if you or someone you know has breast cancer? Exercise is still one of the best forms of medicine and can influence survivability and quality of life. Another study published in 2008 in the Journal of Clinical Oncology looked at women who had breast cancer and showed:
Women who got the equivalent of at least two to three hours of brisk walking each week in the year before they were diagnosed with breast cancer were 31% less likely to die of the disease than women who were sedentary before their diagnosis.
Compared with women who were inactive both before and after diagnosis, women who increased physical activity after diagnosis had a 45% lower risk of death
On the flip side, women who decreased physical activity after diagnosis had a four-fold greater risk of death.
That is some pretty powerful medicine. So if you are exercising, it’s a pretty great life insurance policy, and if you are not, what’s stopping you?