PET/CT WITH 68GA-PSMA-11 IN DETECTION OF PRIMARY TUMOR AND RECURRENCE OF PROSTATE CANCER

Abstract

Purpose: To study the diagnostic value of PET-CT with 68Ga-PSMA-11 in the diagnosis of a primary prostate cancer, preoperative staging, and the detection of recurrence of prostate cancer (PCa).

Methods: 28 patients aged 64.7 ± 8.74 years were included. 10 patients primary prostate cancer, and 18 patients with biochemical recurrence of the disease after radical treatment were examined. All patients underwent PET-CT with 68Ga-PSMA-11 according the whole body protocol. Interpretation of images was performed visually and quantitatively by calculation of SUL max.

Results: High focal or diffuse 68Ga-PSMA-11 uptake was found in prostate parenchyma in patients with primary prostate cancer. Additionally metastases in regional lymph nodes were diagnosed in 4 patients and bone metastases were found in one patient. The correlation between 68Ga-PSMA-11 uptake level and Gleason index in the primary tumor (R Spearmen = 0.25, p = 0.57) was not observed. PET-positive results were obtained in 14 patients and PET-negative results in 4 patients with biochemical recurrence of PCa. The relationship between the frequency of PET-positive results and Gleason index was not revealed (R Spearmen = 0.2, p = 0.39). We found a weak but significant correlation between the frequency of PET-positive results and the prostate tumor stage according to the T category (R Spearmen = 0.49, p = 0.049). In patients with low values of PSA (less than 1.0 ng/ml) in 4 out of 9 cases, PET-negative results were obtained. In patients with PSA level more than 1.0 ng/ml PET-positive results were obtained in all cases.

Conclusions: PET/CT with 68Ga-PSMA-11 allows to diagnose the primary prostate cancer, to establish the stage of the disease in categories N and M, and also to determine the localization and dissemination of the tumor in patients with biochemical recurrence of prostate cancer. The relationship between 68Ga-PSMA-11 uptake in primary tumor and Gleason index was not found. The probability of obtaining PET-positive results in cases of biochemical recurrence is affected by a PSA level above 1 ng/ml and a high stage of the disease according to the T category (T3-T4).