Relationship between the status of positive surgical margins and biochemical recurrence: developing a risk stratification model for biochemical recurrence following radical prostatectomy

To create a risk stratification model for biochemical recurrence by examining the relationship between the positive surgical margin status and biochemical recurrence in patients with prostate cancer after radical prostatectomy. This retrospective study included 3,010 patients who received radical prostatectomy. We analyzed the effect of postoperative pathological results using the Kaplan-Meier method and Cox model regression analysis in patients with no positive lymph node. A risk stratification model incorporating the total positive surgical margin length was constructed based on factors predicting biochemical recurrence. Among the total 1,865 patients, 346 (19%) experienced biochemical recurrence after radical prostatectomy and 377 (20%) had a positive surgical margin. The median positive surgical margin count was 1, and the median total positive surgical margin length measured 1.0 mm. The multivariable regression analysis revealed significant associations between biochemical recurrence and the following factors: preoperative prostate-specific antigen level > 20 ng/mL (p < 0.001), pathological Gleason grade (p < 0.001), extraprostatic extension (p < 0.001), seminal vesicle invasion (p < 0.001), lymphovascular invasion (p = 0.010), and total positive surgical margin length of ≥ 1 mm (p < 0.001). Patients were classified into good-, intermediate-, and poor-risk groups corresponding to the presence of 0, 1, or ≥ 2 factors, respectively. The 5-year survival rates without biochemical recurrence were 93%, 81%, and 47%, respectively. Our risk stratification model for biochemical recurrence after radical prostatectomy incorporates preoperative prostate-specific antigen level and pathological results, thereby aiding in patient counseling and the selection of appropriate adjunctive therapy after radical prostatectomy.