A Drop-in Gamma Probe for Minimally Invasive Sentinel Lymph Node Dissection in Prostate Cancer Preclinical Evaluation and Interim Results From a Multicenter Clinical Trial

PurposeThis study evaluated the performance of a drop-in gamma probe for prostate cancer (PCa) sentinel lymph node dissection (SLND) in a pelvic phantom, porcine model, and in PCa patients as part of an ongoing prospective multicenter clinical trial.MethodsTwo design variants of the drop-in gamma probe (SENSEI; Lightpoint Medical Ltd) were assessed in the pelvic phantom, and the preferred design was evaluated in a porcine model with clinically representative volumes and Tc-99m activities. In the clinical trial, radical prostatectomy, SLND, and extended pelvic lymph node dissection were performed the day after Tc-99m-nanocolloid injection and imaging. Sentinel lymph nodes (SLNs) were detected with the drop-in probe and a rigid laparoscopic gamma probe (RLGP). An interim analysis was performed after 10 patients were recruited.ResultsThe narrow field of view probe design outperformed the wide field of view design in the pelvic phantom (detection rate, 100% vs 50%). In the porcine model, all activity concentrations could be successfully detected. The drop-in gamma probe successfully detected SLNs in all 10 patients (detection rate, 100%). Two of the SLNs identified by the drop-in gamma probe could not be found with the RLGP. No false-negative cases and no adverse events related to the SLND procedure or the drop-in gamma probe occurred.ConclusionThe drop-in gamma probe meets the usability and performance requirements for SLND in PCa and provides performance advantages over the RLGP. The final clinical study results will confirm the performance of the technique across multiple sites.

Automated summary

This study evaluated the performance of a drop-in gamma probe for SLND in PCa patients. The probe successfully detected sentinel lymph nodes in all patients, outperforming the rigid laparoscopic gamma probe. No adverse events or false-negative cases were reported.