[Risk factors of positive surgical margin and multifocal positive surgical margin after robot-assisted radical prostatectomy].

OBJECTIVE

To investigate the incidence, location distribution and risk factors of positive surgical margin (PSM) and multifocal PSM after robot-assisted radical prostatectomy (RARP).

METHODS

We retrospectively and continuously reviewed clinical and pathological data of 926 patients with RARP performed by a single surgeon in Department of Urology, Peking University First Hospital from January 2019 to May 2024. The median age of the patients was 66 (62-77) years, the median body mass index (BMI) was 24.69 (22.86-26.54) kg/m2, and the median preoperative total prostate specific antigen (tPSA) was 10.45 (6.92-16.30) μg/L. Univariate and multivariate Logistic regression were used to analyze the risk factors of PSM and multifocal PSM.

RESULTS

The overall PSM rate was 30.7% (272/926), and the multifocal PSM rate was 13.4% (124/926). The PSM rate in pT3 patients was 45.9% (219/477), while the PSM rate in pT2 patients was 14.0% (62/444). The PSM was primarily distributed in the apex (221 cases, 77.8%), the right peripheral zone (91 cases, 32.0%), and the left peripheral zone (89 cases, 31.3%). Multivariate Logistic regression analysis indicated that preoperative variables including tPSA (OR=1.020, 95%CI: 1.007-1.032, P=0.002), clinical T stage 3 (OR=1.678, 95%CI: 1.110-2.538, P=0.014), International Society Urological Pathology (ISUP) grading of puncture pathology (OR=1.169, 95%CI: 1.034-1.321, P=0.012) was an independent risk factor for PSM; Postoperative variables including pathological T stage 3-4 (OR=3.966, 95%CI: 2.806-5.607, P < 0.001), pathological ISUP group (OR=1.360, 95%CI: 1.181-1.566, P < 0.001) was an independent risk factor for PSM. The independent risk factors for multifocal PSM included BMI (OR=1.101, 95%CI: 1.021-1.188, P=0.013), pathological T stage 3-4 (OR=2.776, 95%CI: 1.350-5.711, P=0.006), and pathological ISUP group (OR=1.307, 95%CI: 1.024-1.667, P=0.032). Multifocal PSM (HR=1.916, 95%CI: 1.110-3.306, P=0.020) was one of the independent factors for biochemical recurrence (BCR)-free survival.

CONCLUSION

The apex was the most common site for PSM after RARP. Clinicopathological characteristics reflecting the degree of tumor progression and aggressiveness were associated with the risk of PSM and multifocal PSM. Patients with multifocal PSM had a higher risk of BCR.