Metastases-yield and Prostate-specific Antigen Kinetics Following Salvage Lymph Node Dissection for Prostate Cancer: A Comparison Between Conventional Surgical Approach and Prostate-specific Membrane Antigen-radioguided Surgery

The first results on 99mTechnetium prostate-specific membrane antigen-radioguided surgery (99mTc-PSMA- RGS) showed promising outcome. Here, we sought to evaluate if this targeted molecular surgical approach might be more effective than conventional salvage lymph node dissection (sLND). We prospectively analysed 42 consecutive patients who underwent sLND based on preoperative 68Gallium (68Ga)-PSMA-positron emission tomography (PET) imaging between 2015 and 2018. In 29 patients, the dissection field was based solely 68Ga-PSMA-PET imaging (conventional surgical approach [CSA]), whereas 13 patients underwent 99mTc-PSMA-RGS. Preoperative characteristics of both groups were similar. Final pathology revealed no metastases in nine CSA patients (31%), whereas all visible lesions on preoperative 68Ga-PSMA-PET were removed in patients who underwent RGS. A PSA decline in general, >50% and >90% within 6 wk was seen in 50%, 29%, and 7% versus 100%, 92%, and 53% in CSA versus RGS groups, respectively (all p<0.01). This is the first comparison of conventional and PSMA-radioguided approach with regards to short-term efficacy of sLND. Although long-term outcome needs to be awaited, RGS offers promising results. PATIENT SUMMARY: We compared two surgical approaches for lymph node dissection in lymph node only recurrent prostate cancer patients. The radioguided approach was superior in removing the affected lymph nodes, resulting in a more pronounced prostate-specific antigen decline.