Obesity doubles the risk of cancer-related recurrence and cancer-related death in patients with esophageal cancer who have undergone surgery, researchers said on Tuesday.

The study was the first to show that obese patients with esophageal cancer have worse outcomes than normal patients following surgery, said lead investigator, Harry Yoon, an oncologist at the Mayo Clinic Comprehensive Cancer Center in a statement.

Researchers studied 778 patients affected with esophageal cancer and found that 36 percent of patients with normal weight survived five years after diagnosis, compared to only an 18 percent chance of a five-year survival rate in patients who had a body mass index higher than 30.

"Obesity is considered a risk factor in the development of this cancer, which is known to be both highly lethal and increasingly common," Yoon said. "But prior to this study, we did not really understand the impact of obesity in this upper gastrointestinal cancer."

Yoon said that the findings may change the way some physicians advise obese patients if the current results are replicated in other studies.

"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," Yoon said.

The results from the study are based on patients who had never smoked, and researchers say that obesity and outcomes in smokers are more difficult to determine because smoking generally causes weight loss and an increase likelihood of death.

Yoon noted that there have been other studies that have liked obesity with poor outcomes in other tumor types, and he proposed that excess weight produces a chronic inflammatory state, which can increase the risk of cancer development and worse outcomes.

Esophageal Cancer is a cancer that forms in tissues lining the esophagus. The National Cancer Institute predicted that 14,710 deaths and 16,980 new cases of esophageal cancer will occur in the United States in 2011.