First experience of active surveillance before systemic target therapy in patients with metastatic renal cell carcinoma

Objective To reveal the outcomes of initial active surveillance (AS), followed by deferred systemic target therapy, in a subpopulation of patients with indolent metastatic renal cell carcinoma (mRCC). Methods We retrospectively reviewed the clinical and pathologic data of patients with mRCC, who initially were monitored by planned AS before systemic therapy because of their preference and asymptomatic or slowly progressive disease, at our institution between 2000 and 2011. The primary outcome measures were progression-free survival (PFS) and overall survival (OS). Results Twenty-nine patients with a metastatic lesion at start of AS were eligible for this analysis. The median age at the start of AS was 69 years. Of these patients, 65% had recurrent disease and 35% were in stage IV. All patients had undergone nephrectomy and 86% had clear-cell carcinoma. No patients were categorized into a poor risk according to Memorial Sloan-Kettering Cancer Center (MSKCC) and Heng criteria. The median follow-up period was 35.4 months. Disease progression was observed in 72% of patients, but only 14% died during the follow-up period. The median PFS time was 26.1 months. After disease progression was observed, only 58% of these patients received treatment. The median OS had not been reached, but 12, 24, and 48 months OS rates were 96.4%, 88.7%, and 83.8%, respectively. Conclusion PFS and OS of patients who underwent AS were acceptable. AS might be a reasonable approach, particularly for patients with prolonged, indolent course of the disease. Further observational studies with a larger sample size might be needed.