Prognostic impact of pT3a subclassification based on extent of extraprostatic extension after robot-assisted radical prostatectomy.

Date 24 November 2018
Event ESMO Asia 2018 Congress
Session Poster display - Cocktail
Topics Prostate Cancer
Surgical Oncology
Presenter Kent Kanao
Citation Annals of Oncology (2018) 29 (suppl_9): ix67-ix73. 10.1093/annonc/mdy434
Authors K. Kanao1, M. Sugie2, S. Morinaga2, H. Muramatsu2, K. Kajikawa2, I. Kobayashi2, G. Nishikawa2, M. Watanabe1, K. Zennami2, K. Nakamura2, M. Sumitomo2
  • 1Urology, Aichi Medical University, 480-1195 - Nagakute/JP
  • 2Urology, Aichi Medical University, 464-0015 - Nagakute/JP

Abstract

Background

International Society of Urological Pathology (ISUP) recently recommends that the amount of extraprostatic extension (EPE) should be quantified in radical prostatectomy specimen reporting, and Epstein et al. proposed pT3a subclassification based on extent of EPE. However, the prognostic impact of the subclassification has not been fully validated in patients treated with robot-assisted radical prostatectomy (RARP). In this study, we evaluated prognostic impact of the pT3a subclassification after RARP.

Methods

A total of 447 consecutive patients undergoing RARP for localized prostate cancer were included in the study. Specimens with EPE were reviewed and the extent of EPE was divided into focal EPE (F-EPE; a few extraprostatic cancer glands on 1-2 slides), and nonfocal EPE (NF-EPE) according to Epstein’s definition. Biochemical recurrence-free rates were calculated using Kaplan-Meier estimates, with pT2, pT2+, F-EPE, NF-EPE pT3a+, and pT3b. Cox proportional hazards models including age, PSA, GS, and above pathological stage were also used to predict biochemical recurrence.

Results

The mean and median follow-up periods after surgery were 19.8 and 14.0 months, respectively. Of the 447 patients, 58 (13.0%) experienced biochemical recurrence during the follow-up period. A total of 98 (21.9%) patients were diagnosed as pT3. Of the pT3 patients excluding 41 patients with positive surgical margin (pT3+), 12 patients had F-EPE and 45 patients had NF-EPE. Kaplan-Meier estimates demonstrated that biochemical recurrence-free rates of the F-EPE was better than the NF-EPE. In multivariate Cox proportional hazards models, hazard ratio of F-EPE (1.074) was almost same as pT2 (1.00; reference) and lower than that of NF-EPE (3.337).

Conclusions

In pT3a patients without surgical margin, patients with F-EPE had better prognosis than patients with NF-EPE following RARP. This result suggests that extent of EPE have a value to be reported on a pathology report.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

Aichi Medical University.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.