Abstract
BACKGROUND: Treatment modification due to adverse events reduces the dose intensity in cancer treatment. The prognostic impact of sunitinib treatment interruption within the initial period of therapy for metastatic renal cell carcinoma (mRCC) remains unknown. PATIENTS AND METHODS: We retrospectively evaluated 97 patients with mRCC treated with first-line sunitinib treatment. The patients were classified into two groups according to the presence of treatment interruption (TI) within the initial two cycles. The prognostic impact of TI was analyzed using the Kaplan-Meier method and log-rank test, and multivariate analyses using the Cox proportional hazard model. RESULTS: Thirty-eight patients (39.2%) experienced an immediate TI. The median progression-free (PFS) and overall (OS) survival were significantly shorter in patients with a TI than in those without (PFS= 6.54 vs. 11.3 months, p=0.0246; OS=16.9 vs. 30.0 months, p=0.0420). Multivariate analyses for PFS and OS showed that TI was an independent factor predicting poorer PFS (hazard ratio(HR)=1.93, p=0.0141) and OS (HR=2.09, p=0.0102). In addition, the relative dose intensity within the initial two cycles was significantly lower in patients with a TI than in those without (52.7% vs. 75.0%, p<0.0001). CONCLUSION: This study showed the significantly negative effect of immediate TI on survival of patients under sunitinib treatment for mRCC. Therefore, the careful monitoring of patient tolerability is required in order to maintain therapeutic efficacy in the early phase of sunitinib treatment.