Cancer Risks Slashed After Bariatric Surgery

Obese individuals who undergo bariatric surgery substantially slash their risk of certain obesity-related cancers, according to a new study presented at the 25th annual meeting of the American Society for Metabolic and Bariatric Surgery in Washington, D.C.

Calling this a "very exciting finding," lead researcher Nicolas Christou, MD, PhD, Director of Bariatric Surgery and Professor of Surgery at McGill University in Montreal, said that "hopefully subsequent studies will shed more light on this subject."

Being overweight or obese raises the risk of several types of cancer including breast, colon, esophageal and kidney, accoeding to the American Cancer Society. Every year 500,000 Americans dieof cancer, and one-third of these deaths are linked to diet, lack of physical activity and being overweight, the group states. Soem cancers, such as lung cancer and mesothelioma, are unrelated to these factors.

Exactly how weight loss surgery reduces cancer risks is not fully understood, Christou says. "A lot of cancer risk is genetic, and we don't alter a person's genetics," he says. "Is it hormonal? We don't know."

Perhaps, he speculates, "it is the inability to eat a 16-ounce perterhouse steak that is barbecued with carcinogens," he says. Many cancer-causing chemicals or carcinogens are created during cooking. Consuming large amounts of red meat has also been linked to certain cancers. Weight loss surgery patients are unable to eat large volumes of food, due to the decreased size of their stomach following surgery.

In the studay, bariatric surgery patients were 78 percent less likely to develop any cancer, when compared with their equally overweight counterparts who did not undergo weight loss surgery. Bariatric surgery patients had an 83 percent reduction in their risk for developing breast cancer and a 68 percent reduction in risk of developing colorectal cancer, when compared with their counterparts who did not have surgery.

Reductions were also seen in risk for other, more rare cancers such as pancreatic cancer, endometrial cancer, kidney cancer, myeloma, melanoma and non-Hodgkin's lymphoma among thse particpants who underwent weight loss surgery; however, these reductions were not statistically significant, Christou said.

The Canadian Bariatric Cohurt Study compared 1,035 bariatric surgery patients with 5,746 controls who were matched for body mass index and did not undergo surgery to lose weight. They were tracked for a maximum of five years. None of the study participants had a history of cancer. During the study period, two percent of people in the surgery group were diagnosed with cancer, compared with 8.5 percent of participants who did not have bariatric surgery.

WASHINGTON, D.C., June 2008 - by Denise Mann