Association between guideline-adherent imaging and overall survival following second-line targeted therapy for metastatic renal cell carcinoma.

Abstract

e15538 Background: NCCN guidelines recommend imaging at 2-6 months after initiation of targeted therapy for metastatic renal cell carcinoma (mRCC). This study assessed the association between guideline-adherent imaging and overall survival in mRCC. Methods: Thirty-six community-based medical oncologists/hematologists reviewed charts for ≤ 15 mRCC patients each. Included patients were aged ≥ 18 years and initiated 2nd targeted therapy in 2010 or later. Patients alive up to month 6 were categorized into 3 groups based on time of first imaging test: early (0-60 days), guideline-adherent (61-180 days), and delayed(> 180 days). Overall survival (OS) was compared using multivariable Cox proportional hazards models adjusted for age, gender, duration of mRCC, prior treatments, comorbidities, metastatic sites, 1st targeted therapy, ECOG and MSKCC status, 2nd targeted therapy, and progression status (based on symptoms or imaging) in the first 6 months on 2nd line therapy. Reasons for imaging were also assessed. Results: Among the 192 patients included in the analysis, 25 received early imaging, 136 received guideline-adherent imaging, and 31 received delayed imaging. First imaging tests were more likely due to worsening symptoms or changes in a palpable mass, as opposed to routine monitoring, among patients with delayed vs. guideline adherent imaging (20.0% vs. 7.1%, P = 0.005). After adjusting for baseline characteristics, guideline-adherent imaging was associated with a 64% lower hazard of death compared to delayed imaging (hazard ratio (HR) = 0.36, 95% confidence interval (CI) 0.14 to 0.93, P = 0.035). Adjusted 1-year survival was 82% in the guideline-adherent compared to 67% in the delayed imaging group. The hazard of death did not differ between those with early vs. guideline-adherent imaging (HR = 1.05, 95% CI 0.35-3.12, P = 0.927). Conclusions: Among patients surviving 6 months after the initiation of 2nd targeted therapy for mRCC, timely first imaging within 2-6 months, consistent with guidelines, was associated with significantly prolonged overall survival compared to delayed imaging. Further investigation is warranted with larger samples.