If you’re considering undergoing weight-loss surgery, you may be aware that these procedures may improve much more than just your waistline. Yes, these procedures may promote therapeutic advantages for weight-related conditions, such as diabetes and heart disease. But now, new research shows that for obese patients, undergoing gastric bypass surgery may impart powerful benefits for cancer!

Canadian researchers have recently reported that this procedure may decrease the incidence of cancer by 80% over the five years following the procedure! Specifically, the incidence of breast and colon cancer — two of the most common types –  may be reduced by 85% and 70% respectively. In August 2007, the proposed reductions of cancer-related deaths were first released.

These new findings show reductions in the incidence of several specific types of cancer. “This is really powerful information,” says Dr. Philip Schauer of the Cleveland Clinic Lerner College of Medicine, and the immediate past president of the American Society of Metabolic & Bariatric Surgery. “It reaffirms that obesity is a profound risk factor for cancer” and shows that “weight loss does seem to affect the development of new cancers.” The American Society for Metabolic & Bariatric Surgery shows that an estimated 205,000 Americans underwent the gastric bypass surgery in 2007. And while this amount is expected to rise by 5% this year, only about 1% of the eligible patients actually receive it.

The study’s subjects – none of which had been previously diagnosed with cancer — included 1,035 patients who had undergone bariatric surgery between 1986 and 2002; 81% of these patients had undergone gastric bypass, specifically. In addition, 5,746 carefully matched obese patients who didn’t have the surgery were included. It was found that those patients who underwent gastric bypass surgery lost an average of 67% of their excess body weight. Over the next five years, the research team observed 21 cancer cases in the surgery group (2%), compared with 487 cases (8.5%) in the control group. When both the latest and the previous findings are combined, they provide dramatic evidence that weight loss reduces the incidence of cancer.

As of yet, researchers are not sure how weight reduction reduces the incidence of cancer. One reason may be that fat is known to secrete estrogen, which plays a crucial role in breast and other cancers. And besides the obvious reduction of fat, these procedures may alter the production of other hormones, as well.

But not all medical professionals agree. Cancer takes a long time to develop, and the study’s subjects were only studied for five years. Prior to undergoing weight loss surgery, patients typically receive mammograms, colonoscopies and endoscopies to screen for cancer. Experts believe that while weight loss may reduce cancer incidences, it may take longer than five years for the effects to be noticed.

However, the study’s researchers stated that the as the subjects were Canadian, they didn’t receive regular cancer screenings. In addition, many of the subjects had undergone surgery up to15 years before the start of the study; this means that any cancer had time to develop.