Monday July 1, 2013 (foodconsumer.org) -- Weight loss may help fight breast cancer as epidemiological studies have linked obesity to increased risk of incident postmenopausal breast cancer, according to a report in the American Society of Clinical Oncology Educational Book by J.A. Ligibel and H.D. Strickler from Dana-Farber Cancer Institute in Boston, MA and Albert Einstein College of Medicine in Bronx, NY.

Obesity has been associated with worse prognosis for both pre- and postmenopausal breast cancer, compared with breast cancer patients who have a normal body weight. This also suggests that weight loss can not only help prevent breast cancer, but also help treat the disease after diagnosis.

Obesity is linked to the levels of certain hormones such as sex hormones, insulin and some adipokines, the authors say and these hormones can promote breast cancer growth.

Insulin is known to have mitogenic/antiapoptotic activity in addition to its role in metabolism of blood sugar, and many breast tumors actually produce high levels of the insulin receptor (IR)-A isoform, making the tumor cells more susceptible to the influence of insulin. 

Also use of an antidiabetic medication called metformin, which lowers the insulin level, was found epidemiologically associated with reduced breast cancer risk among diabetics, and diabetic breast cancer patients responded to cancer treatment more sensitively when they used metformin.  For this reason, trials are ongoing to test the efficacy of metformin as adjuvant breast cancer therapy.

Additionally, lifestyle changes such as diet and physical activity and weight loss benefited breast cancer patients physically and psychologically. (reporting by Jimmy Downs)