Women with a genetic predisposition for breast cancer were 2.5 times more likely to develop a malignancy than women with the same genetic risk who underwent bariatric or weight loss surgery, according to a new study presented at the American Society for Metabolic and Bariatric Surgery (ASMBS) Annual Meeting.

Researchers reviewed data from more than 1.5 million patients with a body mass index (BMI) of 35 or greater between 2010 and 2014 in the National Inpatient Sample (NIS), the largest all-payer inpatient health care database. They then compared the incidence of cancer between a control group of more than 1.4 million patients who did not undergo bariatric surgery against 250,000 patients who did.

Breast cancer incidence in women with severe obesity or a BMI of 35 or higher was found to be 18% whereas incidence for closely matched patients who had weight loss surgery was 7.4%. The study also found that weight loss surgery cut the overall risk of developing cancers linked to obesity by 20%.

"Our findings suggest bariatric surgery could significantly prevent the development of cancer in patients with a higher risk than the average population, even in those genetically predisposed," said Emanuele Lo Menzo, MD, PhD, FASMBS, study co-author and associate program director of the General Surgery Residency Program at Cleveland Clinic Florida in Weston. According to Lo Menzo, the effect that the researchers observed in patients genetically predisposed to developing breast cancer was remarkable.

According to the American Cancer Society, having more fat tissue can increase a patient’s chances of developing breast cancer due to raised estrogen levels. Overweight and obesity are associated with an increased risk of 13 types of cancer, which accounted for approximately 40% of all cancers diagnosed in the United States in 2014, according to the press release.

Further studies are needed to determine the factors, such as weight loss, that may have led to a risk reduction in breast cancer for patients who underwent weight loss surgery.

Reference
  1. Weight-loss Surgery May Counter Genetic Risk for Developing Breast Cancer [press release]. Las Vegas, NV. ASMBS website. Published November 5, 2019. https://asmbs.org/articles/weight-loss-surgery-may-counter-genetic-risk-for-developing-breast-cancer. Accessed November 6, 2019.
  2. Simon, Stacey. How Your Weight May Affect Your Risk of Breast Cancer. American Cancer Society website. Published October 4, 2018. https://www.cancer.org/latest-news/how-your-weight-affects-your-risk-of-breast-cancer.html. Accessed November 6, 2019.