Impact of treatment volume on outcomes for patients with penile cancer at relatively low-volume centers in Japan.

OBJECTIVES: To investigate whether there are differences in treatment approaches, including complications according to the volume of treatment experience for penile cancer, and whether such differences affect patient prognosis. METHODS: We retrospectively analyzed 196 patients with penile cancer treated at 12 university hospitals and affiliated institutions (total of 32 institutions) in the Kyushu-Okinawa region from 2009 to 2020. Cancer-specific survival (CSS) was compared between patients treated at lower-volume centers (defined as institutions with fewer than five cases during the study period) and higher-volume centers (five or more cases). The underlying factors contributing to differences in CSS were also analyzed. RESULTS: Groups treated at lower-volume and higher-volume centers comprised 39 and 157 patients, respectively. No significant differences were observed in patient backgrounds. However, among patients with clinical stage 3 disease, CSS was significantly worse in the lower-volume center group. In that subgroup, significantly fewer patients underwent lymph node dissection. There were no notable differences in other treatments or complications between the two groups. CONCLUSION: A disparity in CSS was observed specifically in patients with clinical stage 3 disease. The lower rate of lymph node dissection in lower-volume centers appears to be a contributing factor to the inferior prognosis in this group. No other differences were found in treatment or complication rates, suggesting that lower-volume centers can deliver care that is comparable to that in higher-volume centers, apart from lymph node dissection.