99mTechnetium-based Prostate-specific Membrane Antigen–radioguided Surgery in Recurrent Prostate Cancer

• Published in: European urology 2019-04, Vol.75 (4), p.659-666
• Main Authors: Maurer, Tobias, Robu, Stephanie, Schottelius, Margret, Schwamborn, Kristina, Rauscher, Isabel, van den Berg, Nynke S., van Leeuwen, Fijs W.B., Haller, Bernhard, Horn, Thomas, Heck, Matthias M., Gschwend, Jürgen E., Schwaiger, Markus, Wester, Hans-Jürgen, Eiber, Matthias
• Format: Article
• Language: English
• Subjects: Positron emission tomography; Prostate cancer; Prostate-specific membrane antigen; Radioguided; Salvage lymph node dissection
• ISSN: 0302-2838; 1873-7560
• DOI: 10.1016/j.eururo.2018.03.013

Prostate-specific membrane antigen (PSMA)–targeted positron emission tomography (PET) can visualize metastatic lesions in recurrent prostate cancer (PC). However, reliable identification of small and/or atypically localized lesions during salvage surgery procedures is challenging. To describe the technique, feasibility, and short-term outcomes of 99mTechnetium (99mTc)-based PSMA-radioguided surgery (99mTc-PSMA-RGS) for removal of recurrent PC lesions. Thirty-one consecutive patients with evidence of recurrent PC on 68Ga-PSMA N,N′-bis[2-hydroxy-5-(carboxyethyl)benzyl] ethylenediamine-N,N′-diacetic acid (68Ga-PSMA-11) PET after radical prostatectomy undergoing 99mTc-PSMA-RGS were retrospectively analyzed. Salvage surgery with intraoperative radioguidance using a gamma probe was performed after intravenous application of 99mTc-PSMA investigation and surgery (mean activity 571 MBq, mean time to surgery 19.7h). Radioactive rating (positive vs negative) of resected tissue was compared with the findings of postoperative histopathological analysis. Best prostate-specific antigen (PSA) response without additional treatment was determined after 8–16 wk postoperatively. Biochemical recurrence- and treatment-free survival was evaluated. In total, 132 tissue specimens were removed, of which 58 showed metastatic involvement on histological analysis. On a specimen basis, radioactive rating yielded a sensitivity of 83.6% (confidence interval [CI]: 70.9–91.5%), a specificity of 100%, and an accuracy of 93.0% (CI: 85.5–96.7%). With 99mTc-PSMA-RGS, all lesions visualized on preoperative 68Ga-PSMA-11 PET could be removed. Moreover, 99mTc-PSMA-RGS detected additional metastases as small as 3mm in two patients. Thirteen patients suffered from complications related to surgery (Clavien-Dindo grade 1: 12 patients; grade 3a: one patient). A PSA reduction below 0.2 ng/ml was observed in 20 patients. Thirteen patients remained biochemical recurrence free after a median follow-up of 13.8 (range: 4.6–18.3) mo. Twenty patients continued to be treatment free after a median follow-up of 12.2 (range: 5.5–18.3) mo. As a new technique for surgical guidance, 99mTc-PSMA-RGS is feasible, and has been proved to be of high value for successful intraoperative detection and removal of metastatic lesions in PC patients scheduled for salvage surgery. Its long-term impact on outcome has to be evaluated. In this report, we evaluated a novel technique to identify metastatic lesions intraoperatively in p