Canada NewsWire
June 18, 2008
MONTRÉAL, QC and WASHINGTON, DC -- A new study of nearly 6,800 morbidly obese patients shows that those who had bariatric surgery reduced the risk of developing cancer by about 80 percent, with breast cancer and colon cancer showing the greatest reductions. The study was presented today here at the 25th Annual Meeting of the American Society for Metabolic & Bariatric Surgery (ASMBS).
Researchers from McGill University in Montreal, Quebec, Canada compared 1,035 patients who had bariatric surgery between 1986 and 2002 with 5,746 patients who did not have surgery, matching them by age, gender, and duration of morbid obesity diagnosis. None of the patients in either group had previously been diagnosed with cancer.
A total of 21 patients (2%) were diagnosed with cancer in the surgery group while 487 patients (8.5%) were diagnosed with cancer in the non-surgical group during the five-year follow up period. A patient was considered to have cancer if at least one mention of the diagnosis or treatment was detected in hospital or physician records. Patients who had bariatric surgery lost on average more than 67 percent of their excess body weight.
"The connection between obesity and several cancers is well established," said Nicholas Christou, MD, PhD, the study's lead author and Director of Bariatric Surgery and Professor of Surgery at McGill University. "This is one of the first studies to suggest that bariatric surgery may prevent the development of cancer in a statistically and clinically significant percentage of people who are morbidly obese."
The incidence of breast cancer was reduced by 85 percent and the incidence of colon cancer was reduced by 70 percent in the bariatric surgery group. In the surgery group, 12 people were diagnosed with breast cancer and two were diagnosed with colon cancer, while 362 were diagnosed with breast cancer and 35 were diagnosed with colon cancer in the non-surgical group.
The incidence of other cancers was also reduced though they did not approach clinically significant levels due to the low number of patients reporting. The incidence of pancreatic cancer was reduced by 70%; skin cancer by 60%; uterine cancer by 15%; and non-Hodgkin's lymphoma by 50%. According to the American Cancer Society, being overweight or obese increases the risk of several cancers, including cancers of the breast (among women past menopause), colon, esophagus, kidney, and other organs. Each year about 550,000 Americans die of cancer with one-third of these deaths linked to diet, lack of physical activity and being overweight.(1),(2)
In 2007, the ASMBS reported that an estimated 205,000 people in the U.S. had bariatric surgery. According to guidelines issued by the National Institutes of Health (NIH), bariatric surgery is indicated for people with a body mass index (BMI) of 35 or more with an obesity-related condition or a BMI of 40 or more. People who are morbidly obese are generally 100 or more pounds overweight.
The most common methods of bariatric surgery are laparoscopic gastric bypass and laparoscopic adjustable gastric banding (LAGB). In gastric bypass, the stomach is reduced from the size of a football to the size of a golf ball and food is made to bypass part of the small intestine. In LAGB, a silicone band is wrapped around the upper part of the stomach to restrict the amount of food the stomach can hold. The amount of restriction is adjusted by adding or removing saline from the band.
Two landmark studies, published in the New England Journal of Medicine in August 2007, showed patients with morbid obesity who had bariatric surgery lost significant weight and are significantly less likely to die from heart disease, diabetes and cancer seven to 10 years following the procedure than those who did not have surgery.(3),(4) A 2004 study in the Journal of the American Medical Association showed that bariatric surgery resolved or improved type 2 diabetes in 86 percent of patients and resolved sleep apnea in more than 85 percent of patients(5).
The Agency for Healthcare Research and Quality (AHRQ) recently reported that bariatric surgery is safer than ever. The risk of death from bariatric surgery has declined from 0.89 percent in 1998, to 0.19 percent in 2004.(6)
About 64 million or 32 percent of adults in the U.S. are considered obese, which is associated with many other diseases and conditions including type 2 diabetes, heart disease, sleep apnea, hypertension, asthma, cancer, joint problems and infertility. The direct and indirect costs to the healthcare system associated with obesity are about $117 billion annually.
The ASMBS is the largest organization for bariatric surgeons in the world. It is a non-profit organization that works to advance the art and science of bariatric surgery and is committed to educating medical professionals and the lay public about bariatric surgery as an option for the treatment of morbid obesity, as well as the associated risks and benefits. It encourages its members to investigate and discover new advances in bariatric surgery, while maintaining a steady exchange of experiences and ideas that may lead to improved surgical outcomes for morbidly obese patients. For more information on the ASMBS, visit www.asmbs.org.
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