Their 778-patient study, which appeared in the Dec. 1 issue of the Journal of Clinical Oncology, found that five-year survival in obese patients — those with a body mass index of 30 or higher — with esophageal cancer was 18 percent, compared to 36 percent in patients of normal weight.
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The research is the first to find that obese patients with esophageal cancer have worse outcomes following surgery than patients with a normal weight, says lead investigator, Harry Yoon, M.D., an oncologist at the Mayo Clinic Comprehensive Cancer Center.
“Obesity is considered a risk factor in the development of this cancer, which is known to be both highly lethal and increasingly common,” he says. “But prior to this study, we did not really understand the impact of obesity in this upper gastrointestinal cancer.”
If validated in another study, the findings may change the way some physicians counsel obese patients with this disease Dr. Yoon says.
“As an oncologist, I did not typically speak to my patients about excess body weight as part of their care, because we are more often concerned about weight loss and maintaining proper nutrition, but that may change. It would be helpful to be able to offer patients some measures that they can take to possibly impact their prognosis,” he says.
The study’s findings applied to patients who had never smoked. Links between obesity and outcomes in smokers are more difficult to determine, because smoking is known to reduce weight and increase the likelihood of death. All the patients studied were treated at Mayo Clinic, and had undergone esophagectomy (removal of the esophagus), which is potentially curative.
Dr. Yoon says studies that have linked obesity with poor outcomes in other tumor types have proposed that excess weight produces a chronic inflammatory state, which can raise the risk of cancer development and worse outcomes.
The study was funded by the National Cancer Institute and the National Center for Research Resources.
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