Measuring visceral fat could help stratify prognosis in women with renal cell carcinoma

Measuring visceral fat area via CT could help stratify prognosis for women with renal cell carcinoma (RCC), and radiographic analyses could further guide therapeutic and surgical decisions, according to a study published in Radiology’s March edition.

The idea of quantifying visceral fat to aid RCC diagnosis and treatment isn’t new, corresponding author Joseph E. Ippolito, MD, PhD, and colleagues wrote, but it may never have been approached correctly. To say results haven’t been clear would be an understatement. One study showed increased absolute visceral fat was protective in patients with advanced RCC, while another showed detrimental effects and a third suggested fat had no bearing on survival outcomes in RCC patients.

The common denominator underlying all of those trials, Ippolito et al. wrote, was the fact that they failed to account for any gender disparities among study populations.

“Sex differences in RCC exist,” the authors said. “On the phenotypic level, men with these tumors present with larger tumor size, higher grade and higher stage relative to women. On the molecular level, RCC exhibits robust molecular differences, including sex-specific mutation incidence and survival.”

As they age, men are more prone to accumulating abdominal visceral fat, while women tend to build up more subcutaneous fat, which has been suggested to have cardioprotective qualities. Increased visceral fat, on the other hand, contributes to insulin resistance, metabolic syndrome and cardiovascular risk, and is linked to poorer outcomes for patients with colorectal and pancreatic cancers.

Ippolito and his team designed their study to center around sex differences, pulling 222 participants with clear cell RCC from the Cancer Imaging Atlas. Using computed tomography, the researchers segmented pockets of body fat into subcutaneous and visceral fat areas before calculative their relative areas. They also evaluated key mutations in clear cell RCC for association with relative visceral fat areas and tumor glycolytic profiles.

According to the study, results suggested women with relative visceral fat areas (rVFAs) greater than 30.9 percent had an increased risk of death compared to men. Glycolytic gene expression stratified both sexes, the authors reported, and the combination of a low rVFA and low glycolysis was able to identify 19 women with “excellent” overall survival. No significant differences were noted in tumor mutations between patients with high and low rVFA.

“Sex differences in visceral fat and tumor glucose metabolism may provide a new risk stratification system for patients with clear cell RCC,” Ippolito and colleagues wrote. “Additional prospective analyses that investigate sex-specific differences in visceral fat, cancer metabolism and its relation to overall survival in cancers, including RCC, are urgently needed.”