PurposeVarious strategies have been used to treat patients with nonpalpable prostate cancer (T1c). As one of the treatments for this stage, a radical prostatectomy was performed and the outcomes were evaluated.MethodsBetween 1993 and 2002, 117 patients with T1c received a radical prostatectomy and their follow-up were examined by the end of 2013. Patients were classified according to risk groups using prostate-specific antigen (PSA) and Gleasson score, and outcomes of respective groups were compared.ResultsApproximately 60% of patients were in low risk group, and the remaining patients were grouped into the intermediate or high risks in half. In 22% insignificant cancer was detected. Biochemical failure occurred in 14%. One patient exhibited bone metastasis, but no deaths from prostate cancer ware observed. The five and ten year overall survival rates were 92% and 75%, respectively, and the biochemical failure-free survival rates were 92% and 89%, respectively. No different outcomes were observed for the different risk groups in the overall and biochemical failure-free survival rates. T1c tumors contain a certain range of various stages of tumors, but most patients experienced favorable outcomes.ConclusionRadical prostatectomy as monotherapy is one of the treatment option for T1c prostate cancer patients, who have a long life span and belong to intermediate or high risk groups.