Majority of patients (pts) with ccRCC at first line (1L) treatment are classified in the IR subgroup according to International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model. IR represents a heterogeneous class of pts while frontline strategies will be chosen on prognostic selection. The aim of this study is to better characterize IR pts.
Retrospective analysis was performed from IGReCC (Institut Gustave Roussy Renal Cell Carcinoma) database. Overall survival (OS) was defined from start of 1L therapy to death or last follow-up. A multivariable Cox model with backward selection procedure (alpha level = 0.01) and a Classification and Regression Tree (CART) analysis were performed to identify which prognostic factors of IMDC score (time from diagnosis to treatment [DDT] < 1 year, Karnofsky Performance Status [KPS] < 80%, Hemoglobin < lower limit of normal [LNL], neutrophils > upper normal level [UNL], platelet > UNL, calcium > UNL) were associated to OS in IR pts.
From 2005 to 2016, 777 pts with ccRCC were treated with an anti-VEGF first line therapy. Among 571 evaluable pts for IMDC score, 199 (35%) pts were classified as good risk, 82 (14%) as poor risk and 290 (51%) as IR. Median OS for IR pts was 24 months (mo). Within the IR population, only platelet (PLT) count was significantly associated to OS with a hazard ratio 1.88 (95%CI 1.27-2.88) p = 0.0017. Median OS for pts with PLT > UNL was 18 months (mo) [95%CI 12-23] versus 29 mo [95%CI 21.4-35.7] for pts with normal PLT count. Therefore, the selection of PLT count was confirmed on bootstrap samples and was also selected for the first split of the CART-tree analysis.
Pts in the IR group have a heterogeneous prognosis. Elevated PLT count seems identifies a subgroup of pts with poor outcome in the IMDC intermediate-risk population with ccRCC.
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All authors have declared no conflicts of interest.