A new research has found that dramatic weight loss in formerly obese women resulting from bariatric surgery decreases the risk of endometrial (uterine) cancer by 71 percent.
Researchers at the University of California, San Diego School of Medicine and Moores Cancer Center, also found that the risk of cancer reduces by as much as 81 percent if normal weight is maintained after surgery.
The findings indicate obesity may be a modifiable risk factor for endometrial cancer, and bariatric surgery a viable option for eligible patients.
First author Kristy Ward, senior gynecologic oncology fellow at UC San Diego, said that estimating from various studies that looked at increasing BMI and endometrial cancer risk, a woman with a Body Mass Index (BMI) of 40 would have approximately eight times greater risk of endometrial cancer than someone with a BMI of 25.
Bariatric surgery is often the last resort for obese patients after all other non-surgical weight loss efforts have failed.
A number of biological mechanisms link obesity to endometrial cancer. Excessive adipose or fat tissue, for example, raises circulating levels of estrogen, which is associated with tumor creation and metastasis.
Obesity also causes chronic inflammation, boosting insulin resistance and increased estrogen levels.
Ward said that the majority of endometrial cancers are estrogen-driven and in a normal menstruating woman, two hormones control the endometrium (inner lining of the uterus).
Ward explained that estrogen builds up the endometrium and progesterone stabilizes it and a woman with excess adipose tissue has an increased level of estrogen because the fat tissue converts steroid hormones into a form of estrogen
"So there is too much estrogen, causing the endometrium to build up, but not enough progesterone to stabilize it. The endometrium continues to grow and can undergo changes into abnormal tissue, leading to cancer," she said.
Bariatric surgery has been shown to reduce the impact of these factors: hormone levels become normal; inflammation decreases; insulin resistance drops; weight loss allows for increased physical activity and improved overall health.
The study is published in the April issue of Gynecologic Oncology.
