The influence of extent of surgical margin positivity on prostate specific antigen recurrence

Background: Positive surgical margins are an adverse prognostic factor in patients undergoing prostatectomy for prostate cancer. The extent of margin positivity varies and its influence on clinical outcome is uncertain. Aims: To evaluate the linear extent of margin positivity and the number and location of positive sites as prognostic indicators in a series of prostatectomy specimens evaluated with the whole mount technique. Methods: Eighty six consecutive margin positive prostatectomy specimens were evaluated, and all pathology data were collected prospectively. The linear extent of margin positivity was measured with an ocular micrometer and the total extent of all positive sites was summed. The total number of sites with positive margins and anatomical sites of the positive margins were analysed. Results: The linear extent of margin positivity ranged from 0.01 to 68 mm ( mean, 6.8; median, 3.0) and was associated with prostate specific antigen (PSA) recurrence in univariate logistic regression ( p = 0.031). In addition, the extent of margin positivity weakly correlated with preoperative PSA ( p = 0.017) and tumour volume ( p = 0.013), but not with age, prostate weight, Gleason score, pathological stage, or perineural invasion. The total number of positive sites was significantly higher in patients with PSA recurrence ( p = 0.037). The location of the positive margin site was not associated with PSA recurrence. The extent of margin positivity correlated with PSA recurrence in univariate analysis, although it had only marginal predictive value when adjusted for Gleason score ( p = 0.076). Conclusions: The extent of margin positivity correlates with PSA recurrence in univariate analysis, although it has no predictive value independent of Gleason score.