Robot-assisted radical prostatectomy with intraoperative assessment of surgical margin (per the CELPM protocol)

Background. Decision on using nerve-sparing technique during robot-assisted radical prostatectomy (RARP) involves a compromise between oncological safety and preservation of erectile function affecting patients' quality of life. One of the approaches to decreasing oncological risks of nerve-sparing technique is intraoperative histological examination of prostate regions adjacent to neurovascular bundle.

Aim. To evaluate the efficacy of express intraoperative histological examination of prostate regions adjacent to neurovascular bundle (CELPM protocol) during nerve-sparing RARP.

Materials and methods. Between March 2019 and October 2025 at the S.P. Botkin Moscow Multidisciplinary Scientific and Clinical Center of the Moscow Healthcare Department, nerve-sparing RARP with express histological examination of the lateral prostate margin was performed in 58 patients. All surgical interventions were performed using Si and Xi da Vinci models through transperitoneal access by two surgeons. Express and final histological examinations of all samples were performed at the Division of Pathological Anatomy of the Center. Presence of tumor tissue in the stained resection margin was considered a positive result of the examination.

Results. Mean time to CELPM was 35 min. Mean operative time was 190 min. Unilateral and bilateral preservation of the neurovascular bundle was performed in 22.4 and 77.6 % of cases, respectively. Risk of recurrence was intermediate in 17.2 % of cases and high in 72.4 %. of cases. Extraprostatic tumor extension per the final histological examination was observed in 22.4 % of patients. The CELPM protocol showed tumor tissue in the resection margin in 23 % of cases. Planned histological examination of secondarily resected neurovascular bundles confirmed tumor process in 10 of 11 cases (90.9 %). In 1 case, oncological process in secondarily resected tissue was not confirmed. Tumor tissue in the resection margin during planned histological examination of the gross specimen (prostate, seminal vesicles, parts of the distal urethra/bladder neck) was found in 9 (15.5 %) of 58 cases. It is important to note that in all cases it was found outside the scope of previous express histological examination.

Conclusion. The use of express histological examination technique (CELPM protocol) during nerve-sparing RARP allows to intraoperatively evaluate the status of resection margin which allows to resect the neurovascular bundles with tumor tissue during a single surgery decreasing the risk of early biochemical recurrence. This technique might extend the indications for nerve-sparing RARP, especially in patients with intermediate and high risk.

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