Impact of positive surgical margins (PSMs) after robotic prostatectomy on biochemical recurrence (BCR): Multicenter analysis

Objective: To study and analyze any correlations between positive surgical margins after RARP and biochemical recurrence. Methods: We enrolled 105 patients who underwent robot-assisted radical prostatectomy (RARP) from 2016-2020 with PSMs on final pathology, all performed or supervised by a senior surgeon in two tertiary referral center. Pathology has been described indicating also the area (apical, base, mediolateral, anterior, or multiple) and the extent of PSMs: focal (& LE;3 mm) or extensive (>3 mm). Cox univariable and multi-variable regression models were used to find the correlation between clinico-pathologic factors: age, local staging, PSA, grading, area, and size of PSMs). Results: We found a good correlation between PSA and grading and between PSA and local staging (T) (p < 0.001). There was no clear correlation between the PSM area with grading nor with T staging. There is a statistically significant correlation between extensive PSM and the worsening of grading and local staging (p < 0.001). BCR rate also has a strong correlation with the worsening of grading and local staging (T) (p < 0.001). A relevant fact is the difference between the BCR rate in the apical and base PSM (34.88%vs 62.5%; p < 0.001) which are the most frequent locations of PSMs. Discussion: PSMs remain a predictor of BCR but which may have controversial significance. The likelihood of BCR increases as grading or local staging gets worse. However, apical PSM is a relatively less powerful predictor of postoperative BCR. This can help to better select patients for subsequent RT, which still causes important side effects.