Weight-loss Surgery Can Cut Cancer Risk, Study Shows
ScienceDaily (June 19, 2008) —
Mini-Gastric Bypass allows morbidly obese patients to lose up to 85 percent of
their excess weight and to maintain weight loss. The latest study by Dr. Nicolas
Christou shows that gastric bypass surgery can decrease the risk of developing
cancer by up to 80 percent.
The researchers compared 1,035 morbidly obese patients who underwent
bariatric surgery between 1986 and 2002 with 5,746 similar patients with the
same weight profile who did not undergo surgery. Cancer rates in in the Gastric
Bypass group was ** 85 percent lower ** for breast cancer and 70 percent lower
for colon and pancreatic cancers, and was also distinctly lower for several
other types of cancer.
"The relationship between obesity and many forms of cancer is well
established," said Dr. Christou. "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. Christou presented his preliminary results June 18 at the 25th Annual
Meeting of the American Society for Metabolic & Bariatric Surgery.
Weight Loss and Cancer Risk
Last year, an estimated 205,000 people in the U.S. had gastric bypass, gastric
banding , or some other form of bariatric, or weight loss, surgery.
Candidates for bariatric surgery include those who are morbidly obese, which for
most people means being 100 or more pounds overweight or having a body mass
index (BMI) of 40 or more.
A 5-foot, 5-inch person who weighs 245 or more would be considered morbidly
obese, as would someone who is 6 feet tall and weighs at least 295 pounds.
In a study of 900,000 adults followed for 16 years, Calle, et al, found the
death rate from cancer was increased by 52 percent in men and 62 percent in
women when the initial BMI was 40 or more. Cancers of the esophagus, colon and
rectum, liver, gall bladder, pancreas, kidney, non-Hodgkins lymphoma and
multiple myeloma were increased in both men and women. Stomach and prostate
cancer was increased in men. Breast, uterus, cervix and ovary cancer were
increased in women. They estimated, on the basis of this study, that overweight
and obesity could account for 14 percent of all cancer deaths in the United
States in men and 20 percent in women.
The newly reported study included 1,035 morbidly obese patients who underwent
bariatric surgery between 1986 and 2002 and 5,746 patients matched for age,
gender, and duration of morbid obesity who did not have surgery.
During five years of follow-up, 21 (2%) surgically treated patients were
diagnosed with cancer, compared to 487 (8.5%) of nonsurgically treated patients.
The bariatric surgery patients had an 85% lower incidence of breast cancer , a
70% lower incidence of colon and pancreatic cancer , a 50% lower incidence of
non-Hodgkin's lymphoma, and a 60% lower incidence of skin cancer .
Obesity Linked to Many Cancers
Eugenia Calle, PhD, who studies the impact of obesity on cancer for the American
Cancer Society, agrees that more research is needed to understand the role of
weight loss and weight loss surgery in reducing cancer risk.
The list of cancers now recognized as being influenced by obesity is both long
and growing. They include cancers of the breast, colon, kidney, liver, pancreas,
endometrium, and esophagus. There is even evidence that obesity is a risk factor
for leukemia and non-Hodgkin's lymphoma, she says.
Maintaining a healthy weight is shaping up to be a critical component of cancer
prevention.
"After avoiding tobacco, weight control, eating a healthy diet, and staying
physically active may be the most important things people can do -- and weight
control is probably the most important of the three," she says.
"There is every reason to think that people who lose excess weight and maintain
that weight loss are going to have a lower risk of cancer going forward."
