Association of hypothyroidism with improved outcomes in first-line treatment of renal cell carcinoma with sunitinib.

Abstract

466 Background: Sunitinib, a multitarget tyrosine-kinase inhibitor, has become a standard of care for first-line low and intermediate risk metastatic renal cell carcinoma (mRCC). Sunitinib-induced hypothyroidism and hypertension have been correlated with better outcomes in those patients. Methods: Fifty patients with mRCC, treated in the first-line with sunitinib, were retrospective analyzed at one brazilian institution, for overall survival (OS), progression free survival (PFS), overall response rate (ORR) and toxicity. We evaluated clinical and laboratory parameters, such as hypothyroidism (TSH level > 5,5 mIU/L) and hypertension, to identify prognostic factors. Results: The median age of patients was 58 years (range: 37-73 years), 82% were male, 54% were ECOG 0 or 1, and 76% were classified in low or intermediate risk. Nefrectomy was performed in 96% of cases. Lung and bone were the most common sites of metastases. The incidence of hypothyroidism and hypertension during treatment were 40% and 34%, respectively. ORR for the entire population was 40% and it was statistically superior in patients that developed hypothyroidism during treatment (90% vs. 20%; p<0,0001). Median survival and PFS were 21.7 months (10.65-17.70 months, 95% CI) and 14.2 months (15.77-27.58 months, 95% CI), respectively. In univariate analysis, ECOG (p<0,0001), MSKCC criteria (p<0,0001), hypothyroidism (p<00001) and hypertension (p=0,001) were associated with OS. In multivariate analysis, ECOG (p<0,0001), MSKCC criteria (p<0,0001) and hypothyroidism (p<00001) were independent prognostic factors for OS. The most common severe adverse events (G3-4) were asthenia (14%), diarrhoea (6%), neutropenia (14%), thrombocytopenia (10%), hand-foot syndrome (6%) and hypertension (8%). Conclusions: Efficacy in survival and toxicity profile of sunitinib in first-line treatment of mRCC in patients out of clinical trials were comparable to prior studies. Hypothyroidism, MSKCC criteria and ECOG were independent prognostic factors for survival.