Outcomes for Patients with Metastatic Renal Cell Carcinoma Achieving a Complete Response on Targeted Therapy: A Registry-based Analysis.

Abstract

It is currently not known whether treatment with anti-vascular endothelial growth factor agents for metastatic renal cell carcinoma (mRCC) can be safely discontinued in patients achieving a complete response (CR). To assess outcomes for patients with mRCC achieving CR on targeted therapy (TT) and the survival of patients discontinuing TT after CR. A national registry was used to identify patients achieving CR during first-line TT using bevacizumab, sunitinib, sorafenib, or pazopanib. Relationships with outcomes were analysed using a log-rank test. A total of 100 patients achieving CR were identified out of 2803 patients. The median time to CR was 10.1 mo. Median progression-free survival (PFS) from TT initiation was 3.8 yr (95% confidence interval [CI] 2.9-4.6 yr) and the 5-yr overall survival (OS) was 80% (95% CI 70-91%). Patients discontinuing TT within 1 mo after achieving CR and those continuing TT beyond CR had similar OS (CI for difference in 2-yr post-CR OS -13% to 19%; p=0.3) and PFS (CI for difference in 2-yr post-CR PFS -29% to 17%; p=0.7). The limitations include the retrospective, registry-based data analysis. Achievement of CR on TT for mRCC was associated with excellent long-term prognosis. No significant differences in post-CR survival were observed between patients discontinuing TT after the date of CR and those who continued on TT, although the wide CIs cannot exclude important differences between the groups. According to this registry-based analysis, patients with metastatic renal cancer with no signs of disease (complete response) after treatment with targeted agents experience excellent long-term survival even if the treatment does not continue beyond the date of complete response.