Clinical Application of SPECT-CT Imaging with 99mTc-PSMA in Patients with Recurrent Prostate Cancer
Authors:   Department of Nuclear Medicine, Sofia Cancer Center, Sofia, Sergieva Sonya , Mangaldzhiev Radoslav ,   Department of Medical Oncology, Sofia Cancer Center, Sofia, Dimcheva Milena ,   Department of Nuclear Medicine, Sofia Cancer Center, Sofia, Parvanova Veselina ,   Department of Radiotherapy, National Oncological Centre, Sofia, Nedev Kamen ,   Department of Radiotherapy, Acibadem City Clinic, Sofia, Zahariev Zahari ,   Department of Radiotherapy, Uni Hospital, Panagyurishte, Robev Bozhil ,   Department of Medical Oncology, UH “St Ivan Rilsky”, Sofia, Gatsev Ognyan ,   Department of Urology and Nephrology, Military Medical Academy, Sofia Bulgaria, Petkova Kremena ,   Department of Urology and Nephrology, Military Medical Academy, Sofia Bulgaria, Saltirov Iliya ,   Department of Urology and Nephrology, Military Medical Academy, Sofia Bulgaria
Published: November 2022

Introduction: Prostate cancer is the most common malignancy in men in Europe. One of the important clinical problems is the early detection and visualization of recurrence after radical prostatectomy, radiation therapy or other radical topical treatment, in patients with PSA values above 0.2 ng/ml. With the introduction of molecular highly sensitive imaging methods after administration of radiolabeled prostate-specific membrane antigen (PSMA), it became possible to detect early functional changes associated with the development of a metastatic process in this disease, with a negative CT or MRI result. 99mTc-PSMA is a new radiopharmaceutical and is a small ligand that binds to the active core of PSMA. The aim of our study was to evaluate the clinical role of 99mTc-PSMA in imaging local recurrence and/or loco-regional and distant metastases in patients with recurrent prostate cancer and biochemical disease progression. Material and methods: A cohort of 36 prostate cancer patients was evaluated with established laboratory data for biochemical progression of the disease - increase in the serum value of the tumor marker PSA and its doubling time within 6 months. In 3/36 of the patients, prostate adenocarcinoma was accidentally detected after transurethral resection of the prostate. Hormonal and cytoreductive radiotherapy was performed in these patients as a therapy. The remaining 33/36 patients underwent radical treatment of primary cancer after a systematic or MRI/US fusion prostate biopsy. Results: All of these patients underwent a whole body scan followed by a targeted SPECT-CT study, 1–3 hours after intravenous administration of 99mTc-PSMA. The sensitivity of the SPECT-CT test with 99mTc-PSMA for the detection of recurrent prostate cancer in 36 followed patients was 84.37% (27/32), specificity - 100% (4/4) and accuracy - 86.11% 31/36). Conclusion: For the clinical application of 99mTc-PSMA SPECT-CT we can summarize that this method finds the greatest clinical application for early diagnosis of recurrent disease in patients with prostate cancer and biochemical progression, at serum PSA levels ≥0.50 ng / ml, in order to determine a personalized treatment for each individual patient. Key words: Prostate cancer, recurrent prostate cancer, 99mTc-PSMA, SPECT-CT