Evaluation of the Relationship Between Prostate-Specific Antigen Levels, Gleason Scores, and 68Ga-PSMA PET/CT Scan Findings in Prostate Cancer Patients

Abstract

Background: The use of 68-gallium prostatespecific membrane antigen positron emission tomography/computed tomography (68Ga-PSMAPET/CT) scan has recently received particular attention in the evaluation of prostate cancer patients. Objectives: The present study aimed to evaluate the relationship between the prostate-specific antigen (PSA) level, Gleason score, and 68Ga-PSMAPET/CT findings in prostate cancer patients. Patients and Methods: In this cross-sectional study, 80 male patients with a definitive diagnosis of prostate cancer, who were candidates for 68Ga-PSMA PET/CT scan for both initial staging and restaging, were included. Restaging indicated biochemical recurrence, which refers to a detectable level of PSA after being documented undetectable following a definitive primary treatment. All prostate cancer patients, who were not initially treated with a definitive therapy, were excluded from the study. A cutoff value ≥ 4 was considered significant for maximum standardized uptake value (SUVmax) to differentiate benign from malignant 68Ga-PSMA-avid lesions. Any 68Ga-PSMA uptake outside the prostate bed, especially in the lymph nodes, bones, and visceral organs, was considered metastatic. Results: Comparison of the PSA level between two subgroups with and without metastasis demonstrated a higher PSA level in patients with metastatic abdominal lymph nodes and a slightly higher PSA level in patients with metastatic pelvic lymph nodes. No significant correlation was found between the Gleason score and the total PSA. There was also no significant association between the level of PSA and the type of Lymph node involvement (single or multiple) in different involved areas. Besides, there was no significant correlation between the SUVmax and the level of PSA and the Gleason score in different involved areas. Conclusion: The SUVmax value in 68Ga PSMA PET/CT scan provides a reliable predictor for neither the grade of prostate cancer, nor the metastatic status associated with cancer progression. The measurement of total PSA may predict metastasis to the abdominal and pelvic lymph nodes caused by prostate cancer.