Belly fat reduces a woman's chances for surviving kidney cancer, but not a man's, a new study suggests.
The study included 77 women and 145 men with kidney cancer. Half of the women with high amounts of belly fat died within 3.5 years of diagnosis. Meanwhile, more than half of women with low amounts of belly fat were still alive after 10 years.
Researchers at Washington University School of Medicine in St. Louis found no link between belly fat and men's kidney cancer survival.
The findings suggest kidney cancer develops and progresses differently in men and women, the study authors said.
"We're just beginning to study sex as an important variable in cancer," study senior author Dr. Joseph Ippolito said in a university news release. Ippolito is an instructor in radiology.
"Men and women have very different metabolisms. A tumor growing in a man's body is in a different environment than one growing inside a woman, so it's not surprising that the cancers behave differently between the sexes," he explained.
Excess weight is a major risk factor for kidney cancer, but does not necessarily affect a patient's chance of survival. This study suggests, however, that the distribution of body fat affects women's survival odds. But it does not prove a cause-and-effect relationship.
"We know there are differences in healthy male versus healthy female metabolism," Ippolito said. "Not only in regard to how the fat is carried, but how their cells use glucose, fatty acids and other nutrients. So the fact that visceral [belly] fat matters for women but not men suggests that something else is going on besides just excess weight."
This line of research could lead to better ways to treat women with kidney cancer, Ippolito added.
The report was published online recently in the journal Radiology.