Evaluation of pT0 prostate cancer in patients undergoing radical prostatectomy.

Objective: To evaluate the incidence, predictors and oncological outcomes of pT0 prostate cancer (PCa).

Methods: We conducted a retrospective analysis of 20 222 patients undergoing radical prostatectomy (RP) for PCa at the Mayo Clinic between 1987 and 2012. Disease recurrence was defined as follow-up PSA >0.4 ng/mL or biopsy-proven local recurrence. Systemic progression was defined as development of metastatic disease on imaging. Comparisons of baseline characteristics between pT0 and non-pT0 groups were carried out using chi-squared tests. Recurrence-free survival was estimated using the Kaplan-Meier method and compared using the log-rank test.

Results: A total of 62 patients (0.3%) had pT0 disease according to the RP specimen. In univariable analysis, pT0 disease was significantly associated with older age (P = 0.045), lower prostate-specific antigen (PSA; P = 0.002), lower clinical stage (P < 0.001), lower biopsy Gleason score (P = 0.042), and receipt of preoperative transurethral resection, hormonal and radiation therapies (all P < 0.001). In multivariable analysis, lower PSA levels, lower Gleason score, and receipt of preoperative treatment were independently associated with pT0 (all P < 0.05). Seven patients (11%) with pT0 PCa developed disease recurrence over a median follow-up of 10.9 years. All seven patients had preoperative treatment(s) and three had recurrence with a PSA doubling time of <9 months. Compared with non-pT0 disease, pT0 disease was associated with longer recurrence-free survival (P < 0.05). Only one (1.6%) patient with pT0 disease developed systemic progression.

Conclusions: pT0 stage PCa is a rare phenomenon and is associated with receipt of preoperative treatment and features of low-risk PCa. Although pT0 has a very favourable prognosis, some men, especially those who received preoperative treatment, experience a small but non-negligible risk of disease recurrence and systemic progression.