Active surveillance in asymptomatic or minimally symptomatic renal cell carcinoma: Retrospective analyses of a cohort of three oncological centers from Spain.

Abstract

441 Background: Some patients (pt) with metastatic renal cell carcinoma (mRCC) have an indolent course. Treatment toxicities can worsen quality of life. Active surveillance (AS) in paucisymptomatic pts is an option often used but few data is available. Our aim is to analyze the impact of initial AS in a sequential therapy strategy in terms of overall survival (OS). Methods: Data frompt diagnosed with mRCC from January 2005 to December 2013 in 3 centres of Spain were retrospectively analyzed. AS subgroup was defined as pt with ≥6 months (m) between diagnosis and first-line (L) treatment (tto) start. A descriptive analysis and median OS (mOS) were performed comparing pt with or without AS (AS vs. tto <6m). OS curve and medians were estimated using Kaplan Meier Method. A multivariate cox regression analyses with different prognostic factors was also realized. Results: From a cohort of 277 pt with mRCC, 69 pt (25%) were on initial AS and 208 pts on tto <6m (75%). Median time on observation until systemic tto was started on pt on AS was 14 m 95%CI (17.6-26.02). Pt characteristics of AS vs tto <6 m were: median age 63/60; males 70/72%; histology: 94/76% clear cell, 3/12% papillar, 0/4% chromophob; M1 at diagnosis: 22/48%; prognosis (Heng risk criteria): 0/17.% poor, 38.5/57% intermediate, 61.5/25% good; prior nephrectomy: 93/73%; number of metastatic locations (loc): 87/68% ≤2 loc, 12.5/32.5% ≥3 loc; lines of treatment: first L 46/53%, second L 38/23%, and third L 16/24%. When comparing exposure in months to each tto L, pt on AS had longer period of tto in second L (10.06/4.14 m, p=0.014). mOS were: 62 m 95%CI (52.97-71.03) vs. 22 m 95% CI (19.87-24.12) for AS/tto <6 m respectively (p<0.001) with statistical significance after multivariate analysis (Cox regression, HR=0.39; 95% CI, 0.25-0.63). Factors that independently influence on OS were: ≥2 M1 sites and papillar histology, negatively, and prior nephrectomy and >1 year from diagnosis to M1, positively. Conclusions: Our results suggest that AS before starting first L of tto is not a detrimental action in a selected population of mRCC pt with good risk characteristics allowing them to remain free of therapy’s toxicity during a long time period.