Development of a technique for evaluating the presence of malignant cells in prostatic fluid during robotic...

To develop a technique to collect fluid expressed during robot-assisted radical prostatectomy (RARP) to assess whether malignant cells may have been inadvertently introduced into the surgical field.

Men with clinically localized grade group 2 to 5 prostate adenocarcinoma undergoing RARP were identified. Following bladder neck division, fluid expressed via prostatic urethra during seminal vesicle dissection was aspirated (specimen A). After specimen removal, an ex vivo seminal vesicle aspiration was performed as well (specimen B). Specimens were prepared with ThinPrep (Hologic, Marlborough, MA) and stained with 4 immunohistochemical markers: keratin-7, PAX-8, prostate-specific antigen (PSA), and prostatic acid phosphatase (PACP).

Between December 2018 and May 2019, 15 men undergoing RARP were included. Median age was 60 years (range: 47-77), median PSA 8.5 ng/ml (range 5.1-24), and 7 (47%) had AUA high-risk disease. Specimen A had adequate cellularity in 13 patients (87%). Five patients were excluded from assessment of malignancy due to acellularity of specimen A (n = 2) or specimen B (n = 3). Three of the remaining 10 patients (30%) had cytologic features suspicious for malignancy on specimen A. Immunohistochemistry supported prostatic origin with positive PSA and PACP staining and negative PAX8 stains. Specimen B was not suspicious in any patient.

We report a technique for intraoperative collection of fluid expressed during RARP. Three patients with adverse pathologic features had evidence of cancer cells within the operative field. Further work is needed to confirm this observation and to determine whether these cells are associated with adverse oncologic outcomes.