The Value of SUVmax of Gallium-68-PSMA PET/CT in Newly Diagnosed Prostate Cancer

OBJECTIVES: To evaluate the correlation between the intensity of prostate specific membrane antigen (PSMA) expression by Gallium-68-PSMA positron emission tomography/computer tomography (Ga-68-PSMA PET/ CT) and the D’Amico risk classification of newly diagnosed prostate cancer patients. MATERIALS AND METHODS: Retrospective reviews of 61 newly diagnosed prostate cancer patients, who underwent Ga-68-PSMA PET/CT between September 2017 and November 2021. Data of maximum standard uptake value (SUV max) of prostate tissue was collected. The correlation between SUV maximum value and D’Amico risk classification, as well as Gleason score (GS) grade group and prostate specific antigen (PSA) level, was evaluated. For the data analysis, the Kruskal-Wallis test, Pearson correlation, and receiver operating characteristic curve (ROC curve) analysis were carried out. RESULTS: Most of the patients (50 patients, 82%) were in the high risk D’Amico risk classification. The mean SUVmax values of the primary tumor for all patients were 15.7 ± 10.5. The SUVmax values for low and intermediate-risk patients (9.5 ± 4.76) were significantly lower than those of high-risk patients (17.06 ± 10.93) (p-value 0.013). A positive correlation was found between SUVmax values and the GS grade group (p-value 0.025), while there was a low correlation between PSA level and SUVmax values. The cutoff SUVmax value of 8.3 showed a sensitivity (84%) and specificity (63.6%) for the detection of high-risk prostate cancer. CONCLUSION: PSMA expression in primary tumors is significantly higher in patients with higher GS grade groups and high-risk D’Amico staging, but it is not correlated with PSA level. Ga-68-PSMA PET/CT can be used to screen high-risk prostate cancer patients and potentially help in an individualized treatment decision.