Propensity score Matched analysis of cancer-specific survivals between papillary type-2 versus clear-cell renal cell carcinoma

==inizio abstract==

Introduction & Objective:
Clear-cell and Papillary are the most common variant of renal cell carcinoma (RCC). Among papillary RCCs, type-2 papillary (p2)-RCC tends to present with more advanced stage and to have an aggressive behavior compared to type 1 papillary RCC. The objective of this study was to compare cancer-specific survival (CSS) in p2-RCC and matched patients with clear-cell renal cell carcinoma (cc-RCC).
Materials and Methods:
Fifty-five (5.6%) patients with p2-RCC and 975 cc-RCC patients were identified within a prospectively maintained institutional dataset of 1250 patients treated with either radical or partial nephrectomy for renal cancer. Univariable and multivariable Cox analyses were performed to address the prognostic role of age, gender, histologic subtype, surgical treatment, tumor size, pT, pN and cM stages, sarcomatoid features and surgical margins on CSS. Subsequently, 110 cc-RCC cases were selected with a propensity score match and a Kaplan Meier analysis was performed to compare survival outcomes of 55 p2-RCC cases with that of 110 cc-RCC cases.
Distribution of demographic, clinical and pathological data between the two groups was compared and data were summarized in Table 1. At multivariable Cox analysis, age (p=0.031), pT≥2 (p<0.001), pN≥1 (p=0.001), cM1 (p<0.001) and tumor histology were independent predictors of CSS. There were no significant differences in the distribution of demographic and pathologic variables between the two groups of 55 p2-RCC and 110 cc-RCC selected for matched comparison. (Table 1) After matching, CSS of p2-RCC was significantly different than that for cc-RCC patients (Figure 1; log-rank p=0.039). Conclusions: In our series p2-RCC presented as more aggressive disease compared with cc-RCC patients and, after adjusting for significant covariates, p2RCC displayed lower CSS than cc-RCC cases. ==fine abstract==