We evaluated whether the 2002 TNM substages of pathological T2 prostate cancer predict intermediate term biochemical recurrence-free survival.
The cohort consisted of men who underwent radical prostatectomy between January 2000 and June 2008, and had pT2 disease at final pathological evaluation. We excluded patients with prior treatment, less than 6 months of followup or missing data, leaving 1,370 available for analysis, including 340 with pT2a, 35 with pT2b and 995 with pT2c disease. Clinical and pathological characteristics were compared between groups using univariate analysis. Biochemical recurrence-free survival was compared between substages using Kaplan-Meier analysis. A Cox proportional hazards model was used to evaluate tumor substage as a biochemical recurrence-free survival predictor.
Median followup was 21 months. No differences were seen in the likelihood of biochemical recurrence-free survival between T2 subclasses (p = 0.174). No patient with T2b disease had recurrence. The 3 and 5-year likelihood of freedom from biochemical recurrence was 95.5% (95% CI 90.9-97.8) and 93.8% (95% CI 87.3-97.0) for pT2a, and 94.3% (95% CI 91.8-96.0) and 87.5% (95% CI 82.7-91.1) for pT2c, respectively. Multivariate analysis showed that significant predictors of biochemical recurrence-free survival were margin status (HR 2.7, 95% CI 1.3-5.5, p = 0.006), preoperative prostate specific antigen (HR 1.0, 95% CI 1.0-1.1, p = 0.029), pathological Gleason score 7 (HR 2.5, 95% CI 1.1-5.7, p = 0.024) and pathological Gleason score 8-10 (HR 6.2, 95% CI 2.2-17.4, p <0.001). Compared to pathological stage T2a neither pT2b nor pT2c predicted biochemical recurrence-free survival (p = 0.99 and 0.42, respectively).
Current pT2 prostate cancer substages may not have prognostic significance for intermediate term outcomes. If borne out during longer followup, future staging systems may collapse the substages into a single category.