Efficacy of 68Ga-PSMA PET/CT in evaluating lymph node metastasis of prostate cancer / 中华泌尿外科杂志

ABSTRACT

Objective:To study the efficacy of 68Ga-PSMA PET/CT in evaluating lymph node metastases (LNMs) in patients with prostate cancer (PCa). Methods:Patients who recieved 68Ga-PSMA PET /CT examination in the First Affiliated Hospital of Air Force Military Medical University from July 2021 to February 2022 were enrolled. The patients’ age was (64.4±6.1) years old, with median total prostate specific antigen (tPSA) 34.5 (6.1-99.0) ng/ ml, including PSA<10ng/ ml in 12 cases, 10-20ng/ ml in 21 cases, and > 20 ng/ml in 25 cases. Preoperative clinical staging 1 case in T 1 stage, 38 cases in T 2 stage, 16 cases in T 3stage, 3 cases in T 4 stage. Preoperative Gleason score of 10 cases was <7, 20 cases was 7, and 28 cases was > 7. According to D 'Amico risk grouping criteria, there were 8 cases in the low-risk group, 20 cases in the medium-risk group and 30 cases in the high-risk group. Preoperative examination of 68Ga-PSMA PET/CT showed no distant metastasis such as visceral metastasis and bone metastasis. All patients underwent radical prostatectomy and pelvic lymph node dissection. The following patients were excluded patients received preoperative prostate surgery, patients received endocrine therapy, chemotherapy and radiotherapy for prostate cancer before surgery, a history of other malignant tumors in the past 2 years, biopsy pathological diagnosis of neuroendocrine cell prostate cancer and other special types of prostate cancer, prior history of major pelvic surgery, etc. Radical prostatectomy was performed. 38 patients received laparoscopic surgery and 20 patients received robot-assisted laparoscopic surgery. The sensitivity and specificity of 68Ga-PSMA PET /CT for the diagnosis of lymph node metastasis of prostate cancer were calculated according to the comparison of lymph node metastasis in postoperative pathological results and preoperative examination. Results:Postoperative pathological diagnosis Gleason score of 9 cases was <7, 19 cases was 7, and 30 cases was >7. 37 cases were in pT 2 stage, 17 cases in pT 3 stage, and 4 cases in T 4 stage. There were 12 cases (20.7%) of positive resection margin, and 7 cases (12.1%) of lymphatic fistula. There were 10 patients with lymph node metastasis diagnosed by 68Ga-PSMA PET/CT before surgery, and 17 positive lymph node regions. A total of 11 patients were pathologically positive in lymph nodes, and a total of 20 lymph nodes regions were positive. Based on the number of patients, the specificity and sensitivity of 68Ga-PSMA PET /CT in diagnosing lymph node metastasis in patients were 97.9% (46/47) and 81.2% (9/11), respectively. Based on the number of regional lymph nodes, the specificity and sensitivity of 68Ga-PSMA PET /CT for regional lymph node diagnosis were 99.4%(326/328) and 75.0%(15/20), respectively. The specificity of lymph node metastasis in the external iliac group, the internal iliac group and the obturator group were 100.0%(114/114), 99.1%(110/111) and 98.1%(101/103), and the sensitivity was 100.0%(2/2), 60.00%(3/5) and 69.2%(9/13), respectively. Conclusion:68Ga-PSMA PET/CT can be used as a strong tool for precise guidance of PLND in PCa patients.