The effect of cytoreductive radiofrequency ablation (cRFA) on results of therapy with sunitinib or interferon-alpha (IFN) in metastatic renal cell carcinoma (RCC) patients with a small primary tumor.

414 Background: At least 5% of the patients (pts) with small primary RCC initially present with metastasis. The main objective of this trial was to evaluate the role of cRFA in metastatic RCC pts with small primary tumor treated with immuno- or targeted therapy. Methods: Three parallel single-arm prospective studies were conducted. Eligibility criteria were nearly identical for all trials, and included histopathologically confirmed RCC; metastatic measurable disease; size of primary tumor ≤5 cm; good prognosis by MSKCC model; no previous therapy. Study 1: Pts were treated with percutaneous cRFA under CT guide and following IFN, 9 MIU, s.c, 3 tiw. Study 2: Pts received cRFA and following sunitinib in repeated 6-week cycles of 50 mg/day for 4 weeks, followed by 2 weeks off. Study 3: Pts with unresected primary RCC received sunitinib alone. The primary endpoint was a 33% increase in progression-free survival (PFS) over expected 5 months in study 1 and over expected 11 months in studies 2-3 (power 80%; signif...