The Role of PET/CT with 68Ga‑PSMA in the Primary Diagnosis of Prostate Cancer

Abstract

Relevance: Prostate cancer is one of the most frequently diagnosed malignant neoplasms of the genitourinary system in men in the world. Recently, there has been an active introduction into clinical practice of positron emission tomography technology combined with computed tomography (PET/CT) with 68Ga‑PSMA‑617 based on prostate‑specific membrane antigen (PSMA), the capabilities of which significantly increase the effectiveness of the diagnosis of prostate cancer at various clinical stages compared with routine methods used in the staging of prostate cancer.Purpose: To compare the diagnostic effectiveness of PET/CT with 68Ga‑PSMA‑617 with traditional methods of radiation imaging (computed tomography, magnetic resonance imaging and bone scan) in the staging of prostate cancer and to clarify the impact of this technology on the choice of surgical treatment.Material and methods: PET/CT with 68Ga‑PSMA was performed in our center in order to stage the verified prostate cancer in 109 patients aged 48 to 80 years (median 64.5). The selection criteria were: a PSA level of more than 5 ng/ml, the presence of a newly identified, histologically verified prostate cancer, lack of treatment, suspicion of metastatic lesion of the lymph nodes of the pelvis and skeleton. Patients were divided into groups by prostate‑specific antigen level, Gleason score, and d’Amico.Results: In the analysis of PET/CT results and MRI/CT comparison and Bone scan, 56 (51.4 %) of 109 patients showed a change in the TNM stage. A change in the data on the local spread of the tumor with an increase in the stage according to criterion T due to the detection of pathological accumulation of RFP in seminal vesicles was detected in 21 (37.5 %) of 56 patients. Additionally, according to PET/CT data, 13 (23.2 %) of 56 patients were found to have lesions of regional lymph nodes (N). Metastatic lesions of distant lymph nodes (M1a) and bones (M1b), not visualized during routine radiation examination, were observed in 32 (57.1 %) and 36 (64.3 %) of 56 patients, respectively.Conclusions: The use of PET/CT 68Ga‑PSMA‑617 in patients with newly diagnosed prostate cancer at the staging stage allows us to obtain valuable additional information about the local, regional and long‑term prevalence of the pathological process, and in some cases — to change the stage of the disease by TNM (usually by increasing it), which has a significant impact on the tactics of therapeutic measures and the choice of the optimal method of therapy for prostate cancer.