Obesity is, unfortunately, increasingly common in the USA. And it’s linked to an increased risk of major health problems – heart disease, diabetes, and cancer. In women, the risk of endometrial (uterine) cancer is high. It’s estimated that a woman with a Body Mass Index (BMI) of 40 (i.e. ‘morbidly’ or ‘severely obese’) would have roughly an 8 times greater risk of developing endometrial cancer than someone with a normal BMI (less than 25). Researchers at the University of California-San Diego decided to evaluate the effect of surgical treatment of obesity on the frequency of endometrial cancer. Their results are published in the journal Gynecologic Oncology.
The University HealthSystem Consortium database contains information on over 7 million patients. The San Diego researchers identified 103,797 patients who had a history of bariatric surgery for obesity and 44,345 who had a diagnosis of endometrial cancer. The rates of this cancer per hospital admission were calculated, as well as whether those diagnosed at the time of discharge included a history of bariatric surgery, and further, whether there was a diagnosis of obesity.
Analyses showed that the rate of endometrial cancer was 599 cases per 100,000 patients among who did not have a history of prior bariatric surgery. The rate was 1,409 per 100,000 patients in those obese women who had not previously undergone bariatric surgery, whereas it was 408 per 100,000 in those who had had bariatric surgery. Further calculations showed that the relative risk of uterine cancer in women who had bariatric surgery compared with obese women who didn’t have surgery, was 0.29. Women who were no longer obese during follow-up after bariatric surgery had a relative risk of uterine cancer of 0.19 compared to obese women who had not undergone surgery. The findings are clear – obese women who have undergone successful bariatric surgery lower their risk of developing endometrial cancer by 71%, and up to 81% if they keep the weight off.
It’s likely that the reduced risk of uterine cancer is related to a reduction in elevated estrogen levels and in chronic inflammation; both of these are associated with obesity, according to the principal author of the study. Obese people who lose weight by other means are probably going to have this extra benefit, too.