Value of 18F-PSMA-3Q PET/CT in prostate cancer patients with low prostate specific antigen level after radical prostatectomy / 中华核医学与分子影像杂志

ABSTRACT

Objective:To evaluate the value of 18F-prostate specific membrane antigen (PSMA)-3Q PET/CT imaging in prostate cancer patients with serum prostate specific antigen (PSA) less than 1.00 μg/L after radical prostatectomy. Methods:From May 2021 to August 2022, 18F-PSMA-3Q PET/CT images and clinical data of 58 patients with prostate cancer (age 52-82 years) after radical prostatectomy with PSA less than 1.00 μg/L in Chinese PLA General Hospital were analyzed retrospectively. According to the level of PSA, patients were divided into three groups (0-0.19 μg/L group, 0.20-0.49 μg/L group, and 0.50-0.99 μg/L group). 18F-PSMA-3Q PET/CT images were analyzed according to the standardized evaluation criteria of molecular imaging, and lesions with the scores of molecular imaging PSMA (miPSMA)≥1 were defined as recurrent or metastatic lesions. The detection rates of 18F-PSMA-3Q PET/CT for patients in different PSA level groups were compared ( χ2 test). The PSA levels of patients with positive and negative scans were compared by using independent-sample t test. Results:Of the 58 patients, 36(62.1%, 36/58) patients and 85 lesions were found by 18F-PSMA-3Q PET/CT. There was 91.7%(33/36) with oligofocal lesions (1≤number of foci≤3) and 8.3%(3/36) with multiple lesions (number of foci>3). According to the location, 5.2%(3/58) of the recurrent lesions were found in the prostatic bed, 39.7%(23/58) in the bone lesions, 37.9%(22/58) in the pelvic lymph nodes, 12.0%(7/58) in the retroperitoneal lymph nodes and 5.2%(3/58) in the left clavicular lymph node metastases. There were 15 cases in 0-0.19 μg/L group, 22 cases in 0.20-0.49 μg/L group, and 21 cases in 0.50-0.99 μg/L group. The detection rates of 18F-PSMA-3Q PET/CT in the above groups were 5/15, 59.1%(13/22) and 85.7%(18/21), respectively ( χ2=10.33, P=0.006). There was significant difference in PSA level between patients with positive ( n=36) and negative ( n=22) 18F-PSMA-3Q PET/CT scans ((0.48±0.28) vs (0.28±0.25) μg/L; t=2.67, P=0.010). Conclusions:18F-PSMA-3Q PET/CT can be used to detect the recurrence or metastasis in prostate cancer patients with PSA level lower than 1.00 μg/L after radical prostatectomy. In this kind of patients, the common sites of lesions are bone, pelvic lymph nodes, retroperitoneal lymph nodes, left clavicular lymph nodes and prostatic bed, and oligofocal patients are more common.