Obesity-triggered cancers on the rise, women at greater risk

By Sheilah Downey

Cancer caused by obesity has skyrocketed over the past years, according to a European study released today, and women are the hardest hit.

Researchers said results of the study "underlined the urgency of the task and scale of the problems" when facing the global obesity epidemic.

"I must emphasize that we are trying not to be sensationalistic about this," said lead author Dr. Andrew Renehan, of the University of Manchester (UK). "These are very conservative estimates, and it's quite likely that the numbers are, in fact, higher."

More than 124,000 new cancers in 2008 in Europe may have been caused by obesity, and women are more vulnerable due partly to declines in smoking-related cancers, said Renehan at the European Cancer Organization congress in Berlin.

"As more people stop smoking and fewer women take hormone replacement therapy, it is possible that obesity may become the biggest attributable cause of cancer in the next decade," said Renehan, senior lecturer in cancer studies and surgery at the University, in a press release.

Renehan and colleagues estimated the proportion of cancers that could be caused by excess body weight in 30 European countries using data from the World Health Organization and the International Agency for Research on Cancer.

They estimated that in 2002 there were 70,000 cases of obesity-related cancer compared to 124,050 cases in 2008, based on projected figures.

Of those cancers, 3.2 percent were in men, while 8.6 percent were in women.

"The overall size of the burden of increasing cancer incidence should inform health policy," said Renehan. "For example, it is clear that in both relative and absolute terms, obesity-related cancer is a greater problem for women than men."

Hormone replacement therapy (HRT) "masked and diluted the effects of obesity on the incidence of breast cancer," until 2002 when its use dropped dramatically, said Renehan,

"Now that far fewer women are using HRT, it is much easier to see the effect of obesity on the incidence of breast cancer and also endometrial cancer," he said.

The largest numbers of obesity-related cancers was for endometrial (33,421), post-menopausal breast cancer (27,770), and colorectal cancer (23,730), according to the study. Those cancers accounted for 65 percent of all cancers attributed to excess body weight, said researchers.

"In the face of an unabating obesity epidemic," said Renehan, "and apparent failure of public health policies to control weight gain, there is a need to look at alternative strategies, including pharmacological approaches."

Obesity-related cancers in U.S.

In 2002, there were 41,000 new cases of cancer due to overweight and obesity, according to estimates from the National Cancer Institute.

As many as 14 percent of deaths from cancer were reported in men, while 20 percent of deaths in women were due to overweight and obesity. Most of the obesity-related cancers were in post-menopausal breast cancer, endometrial and colorectal cancers.

Research shows that even a five to 10 pound weight reduction will help ease risk factors for obesity-related cancers, according to the NCI.