NEW YORK (Reuters Health) - In the United States, roughly 10 percent of all cancers -- more than 100,000 cases a year -- could be avoided if overweight and obesity did not exist, according to updated statistics on the proportion of cancer due to obesity released Monday.

The new projections stem from a review of published studies, updates to the International Agency for Research on Cancer (IARC) report from 2002, and data from the Nurses' Health Study II, which includes 116,686 women, Dr. Graham Colditz explained at a press briefing at the American Association for Cancer Research's international conference on Frontiers in Cancer Prevention Research underway in Baltimore.

By applying the current US levels of overweight and obesity, Colditz from the Harvard School of Public Health estimated that 14 percent of colon cancers -- over 14,000 cases -- would be avoided if no one was overweight or obese.

Likewise, if no one was overweight or obese, "we would avoid 11 percent of breast cancer -- over 18,000 cases; 49 percent of endometrial cancer, almost 20,000 cases; 31 percent of kidney cancer, over 11,000 cases; 39 percent of esophageal cancer, 5,500 cases; 14 percent of pancreas cancers, 4,500 cases; 20 percent of non-Hodgkin lymphoma cases, over 11,000 cases; and for multiple myeloma 17 percent of cases," Colditz told reporters.

Given the increasing prevalence of obesity in the US, these estimates are conservative, he said.

"We can clearly conclude that adult overweight and obesity cause cancer," Dr. Colditz said, "and increasing rates of obesity in the US are continuing to drive up the burden of these cancers."

The data, he added "reinforce the message to avoid weight gain as an adult and to lose weight and keep it off if one is overweight or obese as this can reduce the risk of cancer in addition to other chronic diseases such as diabetes, heart disease, and stroke."

Evidence is accumulating that losing weight will reduce the risk of cancer, Colditz also said, noting that data from four studies looking at weight and breast cancer suggest that women who lose 5 to 20 pounds significantly reduce their risk of developing breast cancer.