Extensive positive surgical margins (PSM) at radical prostatectomy is strongly associated with an increased risk of biochemical recurrence (BCR), according to new study findings published in BMC Urology.

Of 1275 radical prostatectomies performed in 2 university centers in France, Yoann Koskas, MD, of Hôpital Nord in Marseille, and colleagues identified 189 cases (mean age 71.8 years) with PSM, 115 (60.9%) with focal PSM (fPSM) and 74 (39.1%) with extended PSM (ePSM). Compared with the ePSM group, the fPSM group was significantly younger (70.3 vs 74.1 years) and had a significantly lower mean PSA level (8.1 vs 10 ng/mL). To minimize confounding, no patient had pT3b or pT4, detectable postoperative PSA, seminal vesicle or lymph node invasion, or neoadjuvant or adjuvant treatment.

BCR, defined as a PSA rise to 0.2 ng/mL or higher, occurred in just 12.1% of cases with fPSM (a single PSM of 3 mm or less) compared with 54.1% of cases with ePSM (either a single PSM of more than 3 mm or several positive margins of any length) over a median 8-year follow-up.

In a multivariate model, ePSM was significantly associated with a 6-fold greater risk of BCR compared with fPSM. Furthermore, men with ePSM experienced BCR significantly earlier than men with fPSM: 57.2 vs 89.2 months. Having ePSM significantly decreased BCR-free survival regardless of patients’ pathological stage (pT2, pT3a) or Gleason score. BCR-free survival at 5 years was 86.8% for fPSM vs 49.4% for ePSM; at 8 years, it was 85.1% vs 44.8%, respectively. Metastatic recurrence developed in 1 patient, and no patient died from prostate cancer.

“In the end,” Dr Koskas and colleagues wrote, “the therapeutic dilemma for patients with PSMs following radical prostatectomy is to distinguish those who need adjuvant therapy from those for whom simple monitoring would suffice. While it is still unclear what the best treatment is for patients with PSMs, our data may provide beneficial information regarding how to best proceed, particularly for patients with fPSM.”

With regard to patients with ePSM, the authors noted, it remains unclear whether early treatment could be beneficial. According to the investigators, their study clearly indicates that these patients experienced BCR much more frequently than those with fPSM, “and thus it would appear essential to treat them early. Nevertheless, in these cases we believe it essential that the final therapeutic decision integrate the other prognostic factors (Gleason, preoperative PSA, pT) and life expectancy in order to treat these patients as well as possible.”

Study limitations included the retrospective design and the absence of data on PSM Gleason score. The investigators also did not take into account tumor volume and surgeon experience.

Reference

Koskas Y, Lannes F, Branger N, et al. Extent of positive surgical margins following radical prostatectomy: impact on biochemical recurrence with long-term follow-up. BMC Urol 2019;19:37. doi:10.1186/s12894-019-0470-8