WASHINGTON DC: Belly fat is much bigger a concern than just regular fitness for women.
According to a Washington University School of Medicine-study, belly fat affects the odds of women surviving kidney cancer but not men.
Half of female kidney cancer patients with substantial abdominal fat at the time of diagnosis died within 3 1/2 years, while more than half of women with little belly fat were still alive 10 years later, the researchers found.
For men, the amount of abdominal fat appeared to make no difference in how long they survived.
The findings suggested that kidney cancer may develop and progress differently in women than men.
"We're just beginning to study sex as an important variable in cancer," said senior author Joseph Ippolito. "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."
Excess weight is a major risk factor for the development of kidney cancer, but it does not necessarily portend a poor outcome. Rather, the new study suggests that how long a patient survives after diagnosis is linked not to total fat but to the distribution of body fat, at least for women.
Most methods of estimating body fat rely on just a person's height and weight. But not all fat is the same. The kind you can squeeze - called subcutaneous fat - seems to be mostly harmless. But visceral fat, which lies within the abdomen and encases internal organs, has been associated with diabetes, heart disease and many kinds of cancer.
Visceral fat sits too deep inside the abdomen to be measured accurately with a tape measure around a person's waist. Instead, Ippolito and colleagues analysed cross-sectional CT scans, which are routinely performed on people newly diagnosed with kidney cancer to measure the size of tumors and to look for metastases.
Subcutaneous and visceral fat are located in different areas of the body on a CT scan, making it possible to calculate the proportion of each.
The researchers analysed images from 145 men and 77 women with kidney cancer. The scans were drawn from The Cancer Imaging Archive, a collection of demographic, clinical and imaging data on hundreds of cancer patients.