Morbidly obese patients who have bariatric surgery to lose weight have their cancer risk significantly reduced, compared to those who do not have the operation, a new Canadian study says.

Researchers found that patients who had the weight-loss operation reduced their cancer risk by 80 per cent, compared to patients who did not have the surgery.

The study, which analyzed data from nearly 6,800 patients, was conducted by researchers from Montreal's McGill University. The findings were presented Wednesday at the annual meeting of the American Society for Metabolic & Bariatric Surgery (ASMB) in Washington, D.C.

"This is confirmatory evidence that weight loss is good for you and makes you feel better, makes you feel lighter," said lead study author Dr. Nicolas Christou, director of bariatric surgery and professor of surgery at McGill.

"But the icing on the cake, so to speak, is it can reduce your chance of developing cancer and improve your diabetes, sleep apnea and reduces your risk of dying once you lose the weight."

The study found that incidences of breast cancer were reduced by 85 per cent and colon cancer was reduced by 70 per cent in the patients who had bariatric surgery.

Researchers theorize that fat cells may store environmental toxins that can trigger the development of some cancers. They also think that excess weight may alter hormone levels, which could also influence the development of disease.

Canadian patients who could get some benefit from the surgery will have to get in line. The average wait time across Canada is five years.

"Waiting 5.2 years for this surgery is totally inappropriate and unacceptable," Christou said.

Dr. David Lau of Obesity Canada said there are many benefits to offering this surgery to patients who qualify.

"If we can prevent cancer from occurring altogether, we're not only saving lives, we're improving their quality of life and by helping people, reducing costs to the health-care system," Lau said.

Jennifer Schultz of Montreal had bariatric surgery four years ago. At the time, she weighed 275 pounds.

The 46-year-old lost 130 pounds, and is happy that she has significantly reduced her risk for a host of diseases.

"I feel like I have definitely dodged a bullet by having the surgery at this point in my life," Schultz said.

According to the ASMB, more than 200,000 people had bariatric surgery in the U.S. last year. It is recommended for patients with a Body Mass Index (BMI) of 35 or more if the patient has an obesity related health condition, or for someone with a BMI of 40 or higher.

It is estimated that about 64 million adults in the U.S., or 32 per cent of the population, are obese.

The study subjects who had surgery had either gastric bypass or laparoscopic adjustable gastric banding (LAGB). Gastric bypass involves reducing the stomach from a football size to a golf ball size, and food is made to bypass part of the small intestine. LAGB involves wrapping a silicone band around the upper part of the stomach to limit the amount of food it can hold.

Patients in the study who had surgery lost an average of 67 per cent of their body weight.

Previous studies have shown that bariatric surgery can improve outcomes from heart disease and can cause significant improvement in patients with diabetes and sleep apnea.

Based on a report by CTV's medical specialist Avis Favaro and senior producer Elizabeth St. Philip.