The percentage abundance of sarcomatoid component has a prognostic role in grade 4 non-metastatic clear cell-renal carcinoma

Purpose: Sarcomatoid dedifferentiation represents one of the most aggressive features of clear cell renal cell carcinoma (ccRCC). In this study we evaluated whether grade 4-ccRCC subclassification based on the intratumoral abundance of sarcomatoid features could have a prognostic impact. Methods: A cohort of 212 patients with localized or locally advanced sarcomatoid ccRCC was identified. This population was stratified according to abundance of sarcomatoid features in low-sarcomatoid (LS = < 20% sarcomatoid component; n = 117) and high-sarcomatoid (HS = ≥ 20% sarcomatoid component; n = 95). Estimates of cancer-specific survival (CSS) and recurrence-free survival (RFS) were calculated according to the Kaplan–Meier method and compared with the log-rank test. Multivariable analysis was performed using the Cox proportional hazards regression model to identify the most significant variables for predicting CSS and RFS. Results: Kaplan–Meier survival curves stratified by abundance of sarcomatoid component, showed that CSS and RFS were significantly decreased in patients with sarcomatoid component ≥ 20% (both P < 0.0001). At multivariable analysis by Cox regression modeling, the abundance of sarcomatoid component was an independent adverse prognostic factor for CSS (P < 0.0001) and RFS (P < 0.0001). Conclusion: ccRCC Subclassification based on the abundance of intratumoral sarcomatoid component has a clinical significance. Our study showed that ccRCC subclassification into HS versus LS groups had a prognostic impact in terms of CSS and RFS in non-metastatic ccRCC.