Excess weight and the risk of cancer
According to WHO, obesity has tripled in the past forty years with over 1.9 billion overweight persons worldwide.  Obesity is a bigger challenge today as extra fat in the body enables the production of some hormones and chemicals which increase the risk of diabetes, high blood pressure and even cancer.
There are several ways in which obesity increases the risk of cancer in people:
- Increased insulin levels and insulin growth factor-1 (IGF-1), can help few cancers to develop.
- Obese people are more prone to chronic and low-level inflammation which is also associated with increased risk of cancer.
- Fat tissues produced higher amount of estrogen, which can influence the development of cancers like breast and endometrial cancers.
- Fat cells are also associated with the production of adipokines, a hormone that may trigger or hinder cell growth.
- Apart from these factors, being overweight at birth or repeated weight loss or gain is also associated with cancer development.
Role of bariatric surgery in reducing the risk of cancer:
A study by University of Cincinnati found out that bariatric surgery is linked with up to 33% reduced risk of developing cancer. The effects of bariatric surgery in reducing the risk were more prominent in the obesity-related cancers like colon cancer, post-menopausal breast cancer, pancreatic cancer and endometrial cancer.
Another study done in 2008 to study the effects of bariatric surgery on morbidly obese patients also gave similar results, where it was reported that visits to hospitals for common cancers like breast cancer, significantly reduced after undergoing bariatric surgery.
In a 24 year follow up study at Utah, it was established that post gastric bypass patients have low cancer incidence and 46% lower deaths from cancers compared to similar sized non-operated patients.9
Another long term follow up study on Swedish subjects has established that cancer risk reduction after bariatric surgery happens in women and not in men.10
The data from these studies suggests that bariatric surgery improves the cancer outcomes in most morbidly obese patients, as it lowers the risk of cancer to a significant amount.
- Cancer incidence and Mortality after Gastric Bypass Surgery, Ted D Adams et al. Obesity Surgery;17;4, 2009
- Effects of bariatric surgery on cancer incidence in obese patients in Sweden(Swedish Obese Subjects Study):a prospective controlled intervention trial, Prof Lars Sjostrom et al. The Lancet Oncology, Vol 10, Issue 7, July 2009