Obesity is a known risk factor for a multitude of cancers, including pancreatic, ovarian, and liver, and contributes to an estimated 15–20% of all cancer deaths in the USA. Recent findings from researchers across the USA have shown that modern procedures that target obesity, such as gastric bypass and sleeve gastrectomy, limits cancer prevalence in female patients but not male.
This collaborative study involved a huge multicentre cohort comprising 22,178 patients that had undergone one of a variety of bariatric procedures; these were compared with 66,427 severely obese patients that had not received surgical treatment. Analyses showed that endometrial, postmenopausal breast, and colon cancer incidence fell sharply following bariatric surgery. The bariatric group showed 488 incidences of cancer over 87,071 person-years of follow up, compared to 2,055 incidences over 228,010 person-years in the nonsurgical group. This effect was long-term, with a 33% decrease in cancer incidence at a mean follow-up of 3.5 years when compared to the control.
Researchers noted that females experienced a significant reduction in cancer risk following surgery in this study; this could be due to an uneven male/female split in the study cohort, where >80% of surgical cases were women. However, drastic weight loss can greatly affect circulating hormone concentration, which may impact the development of breast and endometrial cancers because are highly influenced by oestrogen levels, which may explain this disparity.
Dr Daniel P. Schauer, associate professor of medicine at the University of Cincinnati and leader of the study, was enthusiastic about the results. ‘‘In addition to the other health benefits associated with bariatric surgery, the reduction in the risk of cancer is an important reason to consider bariatric surgery for severely obese patients.’’
Collaborators in the study hope that this evidence will help them persuade not only their patients to consider these life-changing treatments, but also decision-makers in government that can help improve the treatments’ availability.