Gastric Bypass Can Cut Cancer Risk

The number of overweight Americans opting for gastric bypass surgery has risen dramatically over the past decade. Last year, an estimated 205,000 people had the surgery, compared with a mere 23,100 in 1997. In addition to dramatic weight loss, gastric bypass surgery may also reduce the risk of dying from diabetes or heart disease by improving or resolving conditions such as high blood pressure and high cholesterol. While those results are impressive in and of themselves, there appears to be another added benefit: gastric bypass surgery may also reduce the risk of cancer by as much as 85 percent.

A new study, which was carried out at Montreal's McGill University, compared 1,035 patients who had bariatric surgery from 1986 to 2002 with 5,746 obese patients who did not have surgery. None of the participants had previously been diagnosed with cancer. In the five year follow-up, researchers found that those having the surgery not only lost an average of 67 percent of their excess body weight, but they had 85 percent lower incidence of breast cancer and a 70 percent lower diagnoses of colon and pancreatic cancers. There was also a 60 percent reduction in skin cancer, a 15 percent reduction in uterine cancer and a 50 percent reduction in non-Hodgkin's lymphoma.

Results showed that, overall, 2 percent of patients who had surgery were diagnosed with cancer, compared with 8.5 percent of those who did not. The researchers believe that this dramatic difference may be due to the loss of excess body fat, which is thought to be responsible for increased hormone production, a major risk factor for breast and colon cancer. "The relationship between obesity and many forms of cancer is well established," said Dr. Nicolas Christou, lead researcher as well as director of bariatric surgery and professor of surgery at McGill. "This is one of the first studies to suggest that bariatric surgery might prevent the risk of cancer for a significant percentage of morbidly obese people."

Dr. Philip Schauer of the Cleveland Lerner College of Medicine, said the study not only confirms findings of two papers last August that showed bariatric surgery reduced overall deaths from cancer, but goes a step further by showing reductions in the incidence of several specific types of cancer. "This is really powerful information," Dr. Schauer said of the study findings. "It reaffirms that obesity is a profound risk factor for cancer" and shows "weight loss does seem to affect the development of new cancers."

However, Dr. Edward H. Phillips, a bariatric surgeon at Cedars-Sinai Medical Center in Los Angeles was less enthusiastic about the study findings. He told the Los Angeles Times the results could be biased since candidates for weight-loss surgery often undergo cancer screenings before the procedure, therefore "it could be we are selecting people out of the population who don't have cancer." He also noted that cancer takes a long time to develop and the patients were only studied for five years. Dr. Christou disagreed, saying that in Canada where the subjects were chosen, such screening "is not the standard of care." He also noted that many of the patients had undergone surgery as long as 15 years before the start of the study, allowing ample time for cancers to develop.

The study comes at a very opportune time, as the U.S. Medicare program is considering reimbursement for bariatric surgery after recent findings show it to have a major impact on Type 2 diabetes, which has reached epidemic proportions in the United States. "We're hoping that these results will help the government and public health authorities realize the importance of this procedure in the fight against the various pathologies associated with obesity," said Dr. Christou, who presented the findings on June 18 at the 25th annual meeting of the American Society for Metabolic & Bariatric Surgery.