Martini-Klinik Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
Introduction: Positron emission tomography / computed tomography (PET/CT) directed against the prostate-specific membrane antigen (PSMA) allows detection of even small and/or atypically localized metastatic prostate cancer (PCa) lesions at low PSA values. In a subset of patients with recurrent oligometastatic localized PCa PSMA-targeted radioguided surgery (PSMA-RGS) might be of value. Recently, a DROP-IN gamma-probe for intraoperative detection of metastatic lesions was introduced to facilitate a robot-assisted minimally invasive approach. Here, we report on our experience and the outcome of the first 16 patients treated with PSMA-RGS using the DROP-IN probe. Methods: We assessed 16 patients treated with robot-assisted PSMA-RGS between 05/2021 and 03/2022. All patients presented with biochemical recurrence after radical prostatectomy (RP) and soft-tissue lesions on PSMA PET. Histological correlation, early PSA responses and Clavien-Dindo complications were evaluated. Results: Median age was 64 years (IQR: 56-70.5 years). Prior to PSMA-RGS, overall median PSA was 0.55 ng/ml (IQR: 0.35-0.82 ng/ml). At robotic PSMA-RGS, intraoperative blood loss was estimated with 50 ml (IQR: 50-100 ml) and OR time was 158 minutes (IQR: 139-173 minutes). Metastatic soft-tissue lesions from PCa metastases could be removed in 15 (94%) patients. Postoperatively, overall median PSA was 0.18 ng/ml (IQR: 0.05-0.27 ng/ml). During the median follow-up of 4.2 months (IQR: 1.0-5.8 months), 4 patients experienced BCR and 1 patient received further therapy. One patient suffered from a Clavien-Dindo complication grade IIIb within three months from surgery (intraabdominal fluid collection necessitating drainage in general anesthesia). Limitations are the retrospective design and lack of a control group, as well as the small cohort. Conclusions: Robot-assisted PSMA-RGS using the novel DROP-IN gamma probe is a promising tool to enhance intraoperative detection of metastatic lesions in PCa during salvage surgery in a minimally invasive fashion. Further studies are needed to confirm our findings. SOURCE OF Funding: None.
