ABSTRACT
BACKGROUND: The current treatment of metastatic renal cell carcinoma (mRCC) with vascular endothelial growth factor (VEGF)-targeted agents is continuous therapy until progression of disease (PD) or unacceptable toxicity. Chronic mild to moderate toxicity and risk of long-term toxicity ensue for some patients. It is hypothesized that patients with an initial response to treatment can maintain disease control off all therapy for a period of time. METHODS: A retrospective study of patients with mRCC who initiated VEGF-targeted therapy between January 2004 and December 2009 at The Cleveland Clinic Foundation, Cleveland, Ohio, or Institut Gustave-Roussy, Villejuif, France, was conducted. Patients had achieved RECIST (Response Evaluation Criteria in Solid Tumors)-defined stable disease or better on therapy, and were then taken off all therapy for reasons not including disease progression. Patient, disease, and therapy characteristics were recorded. The primary objective was progression-free survival (PFS), measured as the time from discontinuation of therapy to RECIST-defined PD. RESULTS: Forty patients were identified. After a median follow-up of 29.7 months (range, 4.2 to 84.7 months), 25 patients (63%) had PD off therapy (median PFS, 10.0 months; range, 1.4-27.2 months). Among these patients, 8 (32%) had progression in sites that were not previously involved with disease. Heng risk group (hazard ratio, 2.49; 95% confidence interval, 1.19-5.22; P = .011) and achievement of a complete response prior to discontinuing therapy (hazard ratio, 0.20; 95% confidence interval, 0.04-0.86; P = .025) were independent predictors of PFS in a multivariable Cox proportional hazards model. CONCLUSIONS: A select subset of mRCC patients achieving stable disease or better on VEGF-targeted therapy can be observed off all therapy. Further prospective investigation is warranted.