Incidence and Short- to Intermediate-Term Oncological Outcomes of Pathological T0 Prostate Cancer After Robot-Assisted Radical Prostatectomy: A Multicenter, Retrospective Cohort Study in Japan (MSUG94 Group)

Background: Pathological T0 (pT0) prostate cancer following radical prostatectomy is uncommon, and its prognostic significance remains unclear, particularly after neoadjuvant hormonal therapy (NHT). We investigated the incidence of pT0 disease in a multicenter Japanese cohort and described postoperative biochemical recurrence (BCR) outcomes. Methods: This retrospective study analyzed 3079 patients who underwent robot-assisted radical prostatectomy at nine Japanese centers between 2011 and 2021. Patients were classified as having pT0 or non-pT0 disease. Because only four pT0 cases occurred without NHT, these are summarized descriptively. Exploratory Kaplan–Meier and log-rank analyses of biochemical recurrence-free survival (BRFS) were performed for the NHT subgroup. Results: Twenty-seven pT0 cases (0.9%) were identified, and 85.2% were identified after NHT. Overall, 399 patients (13.0%) developed BCR. Among patients who did not undergo NHT, the 1- and 2-year BRFS rates were 100% and 100%, respectively, in the pT0 group and 92.4% and 88.1%, respectively, in the non-pT0 group. In the NHT subgroup, the corresponding rates were 92.9% and 92.7%, versus 91.8% and 85.5%, respectively (p = 0.651). Conclusions: pT0 disease after robot-assisted radical prostatectomy is rare and occurs predominantly after NHT. Given the possibility that late-onset recurrences may have been overlooked, the results of this trial should be understood as providing evidence from the short- to intermediate-term perspective.