Nephrometry score correlated with tumor proliferative activity inT1 clear cell renal cell carcinoma.

Objective: To evaluate the association between the RENAL nephrometry score (RNS) and tumor proliferative activity assessed by immunohistochemistry in patients with localized renal cell carcinoma.

Methods: The current study included 145 pathological T1 (pT1) clear cell renal cell carcinomas (ccRCC). Tumor proliferative activity was assessed with the Ki67 index and microvessel density (MVD). RNS was retrospectively assessed in the present study. We divided patients into 3 groups according to RNS (RNS 4-6: low-complexity, 7-9: moderate complexity, and 10-12: high-complexity tumors) and compared the Ki67 index as well as MVD among the 3 groups. The association between the Ki67index/MVD and each component (R, E, N, A, L, h) was also evaluated.

Results: There were 56 low, 84 moderate, and 5 high-complexity tumors. The median Ki67 index of all tumors was 5.34% (interquartile range: 3.28-8.57). The median Ki67 index of low, moderate, and high-complexity tumors was 3.97%, 6.39%, and 11.27%, respectively, with a significant difference among the 3 groups (Kruskal-Wallis test, P = 0.0004). On the other hand, the median MVD of low, moderate, and high-complexity tumors was 14.11%, 14.42%, and 21.22%, respectively, and there were no significant differences among the 3 groups. In terms of each RNS component, there were significant differences in the Ki67 index among the 3 groups in N (P = 0.0101) and L (P = 0.0280) components, respectively.

Conclusions: The revealed association between RNS and the Ki67 index in pT1 clear cell renal cell carcinomas further supports the previous findings that the anatomy of renal cell carcinoma is associated with the malignant potential of localized clear cell renal cell carcinoma, which may provide additional information for treatment decision.