[Value of positive resection margins in patients with pT2 prostate cancer. Implications for adjuvant treatment].

Objective: To analyse the impact on the recurrence-free biochemical survival of tumour involvement of surgical resection margins in patients with localized prostate cancer (pT2) in the prostatectomy specimen and its implications for adjuvant treatment.

Materials And Method: Retrospective study of 536 patients with stage pT2 prostate cancer, treated with radical prostatectomy between 1996 and 2007. Subsequent to the prostatectomy, the following variables were collected: Gleason score, pathological stage, capsular invasion, surgical margins and perineural invasion. We performed a univariate analysis and subsequently adjusted it by means of a Cox proportional hazard model (enter method).

Results: 21.7% presented positive surgical margins and 20.9% developed biochemical recurrence after a mean follow-up of 57 months. 37.9% of the patients with pathological involvement of the resection surgical margins presented biochemical recurrence against 16% that did not have it (p<0.001). In the multivariate analysis, only the surgical margin (p<0.001) and the Gleason score greater or equal to 8 (p<0.001) behaved as independent biochemical recurrence factors. On stratifying the series according to these two variables, we found that the patients with positive surgical margins and a Gleason score of ≤ 7 have a recurrence probability at 5 and 10 years of 35% and 50% against 74% and 87% in the group with positive surgical margins and a Gleason score of ≥ 8 (p=0.002).

Conclusion: Patients with pT2 prostate cancer, positive surgical margins and a Gleason score of ≥ 8 will benefit from adjuvant radiotherapy. 50% of the patients with positive margins and a Gleason score of ≤ 7 will not recur, which means that the indication of adjuvant radiotherapy continues to be controversial.