Clinicopathological significance of 114 cases with positive surgical margin in radical prostatectomy specimens

Abstract

Objective: To analyze the clinicopathological features of positive surgical margins (PSM) after radical prostatectomy and to explore its associated factors. Method: A retrospective analysis was conducted on 274 patients who underwent radical prostatectomy in Beijing Hospital from June 2018 to June 2021. The margins of these specimens of radical prostatectomy were directly inked with black ink. According to the margin status (tumor present versus not), the patients were divided into PSM and negative surgical margin (NSM) groups. The clinicopathological characteristics were compared between two groups, including age, preoperative prostate specific antigen (PSA), number of tumors, tumor's location, postoperative pathological Gleason score, tumor burden and postoperative pathological staging. Results: Among the 274 cases, 114 showed PSM, and 160 showed NSM. PSM accounted for 41.6% of the cases. The mean age was 68.3 years, while the PSM group's mean age was 68.0 years, and that of the NSM group was 68.6 years, with no statistical significance between groups (P>0.05). The mean preoperative PSA was 15.8 μg/L in all patients, 21.5 μg/L in the PSM group and 11.3 μg/L in NSM group. PSA in the PSM group was statistically higher than that in the NSM group (P<0.001). The PSA level (10 μg/L, 10-20 μg/L, and >20 μg/L) was associated with the PSM rate (31.1%, 48.7%, and 69.4%). Regarding tumor numbers, 118 cases had a single focus, including 40 cases with PSM (33.9%). In the 156 cases of multiple foci, 74 cases had a PSM (47.4%). There were statistically more PSM cases in the cases with multi-focal disease (P<0.05). Tumors were seen in the transit zone of 44 cases, while 107 cases showed tumors in the peripheral zone, and 123 cases in the whole zone. The PSM rate was 27.3% (12/44), 40.2% (43/107), and 48.0% (59/123) by tumor location, respectively, but the difference among groups was not statistically significant (P>0.05). The postoperative Gleason scores were 3+3=6 in 51 cases, 3+4=7 in 98 cases, 4+3=7 in 81 cases, and ≥8 in 44 cases, with PSM rates of 19.6% (10/51), 38.8% (38/98), 45.7% (37/81) and 65.9% (29/44), respectively (P<0.001 for rate differences). The tumor burden was <30% in 157 cases, 30%-60% in 91 cases, and>60% in 26 cases, with PSM rate of 21.0% (33/157), 65.9% (60/91) and 80.8% (21/26), respectively (P<0.001 for rate differences). Moreover, there were 181 cases of pathological stage T2 (PSM rate, 29.3%) and 93 cases of pathological stage T3 (PSM rate, 65.6%), with statistical difference in PSM rates (P<0.001). The multivariable logistic regression analysis indicated that preoperative PSA >20 μg/L, postoperative Gleason score ≥8, high tumor burden and pathological stags were different between the PSM and NSM groups (P<0.05). Conclusions: The PSM of radical prostatectomy is closely related to the preoperative PSA level, the number of lesions, postoperative Gleason score, tumor burden and pathological stage. Preoperative PSA level >20 μg/L, postoperative Gleason score ≥8, high tumor burden and pathological stage are independent predictors for PSM.