Active surveillance before sequential targeted therapy in patients with metastatic renal cell carcinoma.

e15582 Background: Some patients (pts) with metastatic renal cell carcinoma (mRCC) have an indolent course. Since new target agents are not exempt from toxicity, initial active surveillance (AS) with deferred targeted therapy is sometimes used in pts with asymptomatic or slowly progressive disease. Nevertheless, little data about its benefit are available. Methods: Pts with mRCC treated at 3 Spanish centers from January 2005 to December 2013 were retrospectively studied. AS cohort was defined as pts in whom systemic therapy start was deferred ≥ 6 months (m) from diagnosis of metastases, although nephrectomy was permitted. The primary objective was to determine overall survival (OS). Secondary objectives were to assess combined progression free survival (cPFS), defined as time from diagnosis of metastases to progression on last line of therapy, and impact of AS on treatment exposure and also identification of main discrimination factors associated with the decision of AS by regression tree analysis. Result...