The research, carried out in Australia, included nearly 800 patients with oesophageal cancer and 1,580 adults without oesophageal cancer. They tracked BMI (body mass index, which compares height to weight) among people with and without oesophageal cancer.
Oesophageal cancer was up to six times as common among very obese people (BMI of at least 40) and about twice as likely among obese people (BMI of 30 or more).
The study authors also found that the risks of developing this cancer were higher among individuals who had gastric acid reflux, which has long been associated with such tumors.
But another big risk factor was obesity. A combination of obesity and acid reflux boosted the risk of this cancer. Men and those under the age of 50 were especially vulnerable, the authors noted adding that smoking and high alcohol consumption also leads to cancer of the gullet.
Most obese people have higher levels of fat tissue in the body that boost insulin production, which in turn increases the amount of circulating insulin-like growth factor.
Researchers say that both these hormones stimulate cell growth leading to cell death - a condition which favours the development of cancers.
Fat cells also produce other hormones, collectively known as adipocytokines, which hasten the cell growth and are involved in inflammatory processes in the body, they say.
These hormones also inhibit a process called apoptosis, in which a faulty cell is prompted to die on its own. Both conditions favour cancer development.
The study doesn't prove that obesity directly causes esophageal cancer but that possibility deserves further study, the authors noted.
Cancer of the oesophagus or gullet develops as a result of cell changes in the lining of the oesophagus.
There are two main types of cancer of the oesophagus: squamous carcinoma, which is more common at the upper end of the gullet, and adenocarcinoma, which is more common at the lower end, particularly around the junction between the gullet and the stomach.
It is thought that smoking and alcohol, among other things, can contribute to cancer of the oesophagus.
