Active surveillance for metastatic or recurrent renal cell carcinoma

Purpose Metastatic renal cell carcinoma (mRCC) sometimes presents with an indolent course without any significant symptoms. Here, the potential impact of active surveillance (AS) on clinical outcomes in asymptomatic or minimally symptomatic mRCC patients was retrospectively evaluated. Methods mRCC patients who were followed up with deferred treatment for the purpose of AS between 2000 and 2012 were enrolled. Patient and disease characteristics, outcomes of AS and subsequent therapies, and predictive factors for rapid disease progression were analyzed. The primary endpoint was time-to-progression (TTP). Results First-line systemic therapy was deliberately deferred in 58 patients. During AS, the best overall responses were stable disease for 48 patients (83 %) and progressive disease (PD) for 10 patients (17 %), and 47 patients ultimately experienced disease progression at the time of data cutoff. With a median follow-up of 31.4 months, the median TTP was 12.4 months (95 % confidence interval 8.4-16.5) and median overall survival was not reached. After univariate and multivariate analyses for TTP, Karnofsky performance status <100 %, liver metastasis, and a time from diagnosis to AS of less than 1 year were found to be predictive factors for a shorter TTP. After PD, 30 patients received systemic treatment (14 sunitinib, 11 pazopanib, 4 immunotherapy, and 1 temsirolimus). The objective response rates were 71 % for sunitinib and 46 % for pazopanib, which were deemed comparable with historical controls. Conclusions A symptomatic or minimally symptomatic mRCC patients can be observed for a prolonged period of time without active treatment.