The value of sex-specific abdominal visceral fat as measured via CT as a predictor of clear renal cell carcinoma T stage

Abstract

Although much is known about how adipose tissue affects the development of clear cell renal carcinoma (ccRCC), little information is available for the utility of sex-specific abdominal visceral fat composition as a predictor of clear cell renal carcinoma (ccRCC) T stage. We conducted CTbased sex-specific abdominal fat measurements in ccRCC patients to assess whether VFA distribution could predict the ccRCC T stage. In total, 253 patients (182 males and 71 females) from our hospital with pathologically confirmed ccRCC (178 low T-stage and 75 high T-stage) were retrospectively reviewed for the present study. Computed tomography (CT) scans were assessed using ImageJ to differentiate between the visceral and subcutaneous fat areas (VFA and SFA), after which the relative VFA (rVFA) and total fat area (TFA) were computed. The relationships between these fat area-related variables, patient age, sex, and BMI, and ccRCC T stage were then evaluated through univariate and multivariate logistic regression analysis to clarify the association between general or sex-specific abdominal visceral fat and T stage. Following adjustment for age, males with high T stage ccRCC exhibited an increased rVFA as compared to males with low T stage ccRCC, with the same relationship being observed among females. This association between rVFA and high T stage was confirmed through both univariate and multivariate models. As thus, sexspecific visceral fat composition is a reliable independent predictor that can identify both male and female patients with high T stage ccRCC.

Association of visceral and subcutaneous adiposity with tumor stage and Fuhrman grade in renal cell carcinoma

“…We investigated continuous VAT and rVAT while several other studies used medians or proportions of VAT 10,14,15,[18][19][20] . Also, most studies were conducted in Asian populations [8][9][10][14][15][16][17][18][19][20] which have been reported to have higher TAT and VAT compared to our Dutch population 30 , implying that results may not be directly comparable.…”

“…We also found no associations of adipose tissue parameters with stage II or III compared to stage I disease. In contrast, Guo et al reported in 253 Chinese patients with ccRCC that patients with high rVAT had increased risk of stage III-IV compared with stage I-II disease, and this relationship was similar for males and females 8 . In a Korean study with 706 localized stage I-II RCC the highest quartile of rVAT had the highest proportion of stage I disease.…”

“…Only few studies investigated associations of VAT, SAT, TAT and rVAT with tumor characteristics by gender. Guo et al reported that higher rVAT was independently associated with higher tumor stage in both males and females but found no associations for VAT, SAT and TAT 8 . On the other hand, Hu et al reported that higher rVAT was associated with higher grade ccRCC in females but not in males 16 .…”

“…It was hypothesized that this potential difference between genders might be due the sex hormone estrogen which is a key regulator of body fat distribution and is higher in females than in males and higher in females with low than those with high rVAT 8,16,27 . Activation of estrogen receptor beta by estrogen has antiproliferative effects and may reduce cell growth, migration and invasive ability in RCC tissue and increase apoptosis 29 .…”

“…Differences in findings between our and other studies may be explained by different reasons. We analysed associations of VAT, SAT, TAT and rVAT with tumor characteristics by gender while other studies did 7,17,18,21 or did not adjust for sex 10,14,15,19,20 or used sex-specific cut-off points 8,16 for VAT, SAT, TAT and/or rVAT. While most studies only performed univariable analyses using means, proportions or linear regression 9,10,14,15,19,20 , we used multivariable logistic regression analysis.…”