Adults with obesity, who achieve weight loss with bariatric surgery can reduce the risk of developing cancer and death related to it, finds a study.

Obesity is a known risk factor for developing cancer and a host of other diseases. The International Agency for Research on Cancer describes 13 types of cancer as obesity-associated cancers such as endometrial cancer, postmenopausal breast cancer, and cancers of the colon, liver, pancreas, ovary and thyroid.

The research, published by JAMA, was associated with a 32 per cent lower risk of developing cancer and a 48 per cent lower risk of cancer-related death compared with adults who did not have the surgery. Bariatric surgery is currently the most effective treatment for obesity.

"Patients can lose 20 to 40 per cent of their body weight after surgery, and weight loss can be sustained over decades. The striking findings of this study indicate that the greater the weight loss, the lower the risk of cancer," said lead author Ali Aminian, Director of Cleveland Clinic's Bariatric and Metabolic Institute.

The study included more than 30,000 Cleveland Clinic patients. A group of 5,053 adult patients with obesity who had bariatric surgery were matched to a control group of 25,265 patients who did not have surgery for their obesity.

After 10 years, 2.9 per cent of patients in the bariatric surgery group and 4.9 per cent of patients in the non-surgical group developed obesity-associated cancer. After 10 years, 0.8 per cent of patients in the surgery group and 1.4 per cent of patients in the non-surgical group died from cancer. These findings indicate that bariatric surgery is associated with a 48 per cent lower risk of dying from cancer.

The study provides the best possible evidence on the value of intentional weight loss to reduce cancer risk and mortality, the researchers said. Numerous studies have shown the health benefits of bariatric or weight-loss surgery in patients with obesity, including control of Type 2 diabetes and a decrease in the risk of the progression of liver disease and serious heart complications in patients with fatty liver.