Patients' preferences for adjuvant sorafenib after resection of intermediate or high-risk renal cell carcinoma in the SORCE trial: What makes it worthwhile?

Abstract

415 Background: SORCE is an international, double-blind, placebo-controlled, phase 3 trial comparing adjuvant sorafenib for 1 year, for 3 years, or observation after resection of intermediate or high risk (as per the Leibovich score), localised renal cell carcinoma (RCC). We determined the survival benefits that SORCE participants judged necessary to make adjuvant sorafenib worthwhile 3 months after starting study treatment. Methods: Participants recruited to SORCE from Australia and selected UK sites completed a validated, self-administered questionnaire 3 months after starting study treatment to determine the minimum survival benefits they judged necessary to make adjuvant sorafenib worthwhile. Scenarios used baseline survival times (without adjuvant sorafenib) of 5 and 15 years; and baseline survival rates (without adjuvant sorafenib) of 65% and 85% at 5 years. Preferences were determined for 1 year of adjuvant sorafenib (versus none) and for 3 years of adjuvant sorafenib (versus 1 year). All tests were 2-sided and non-parametric. This substudy of SORCE was conducted by the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP). Results: The 179 participants were mostly male (72%) with a median age of 57 years (range 29 to 78). Participants allocated sorafenib judged larger benefits necessary to make 1 year of adjuvant sorafenib worthwhile than those allocated placebo: median benefit of an extra 1 year versus an extra 1 month for baselines of 5 years (p=0.004) and 15 years (p=0.02); median benefit of an extra 5% versus an extra 1% for baseline of 65% (p=0.03), and an extra 3% versus an extra 1% for a baseline of 85% (p=0.07). Larger survival benefits were judged necessary to make 3 years of adjuvant sorafenib worthwhile (versus 1 year) regardless of treatment allocation: median benefit of an extra 2 months to 1 year for baselines of 5 years (p=0.02) and 15 years (0.02). Conclusions: Experienced toxicity and duration of treatment are important determinants of patients’ preferences for adjuvant sorafenib in RCC.