Gallium-68-prostate-specific membrane antigen (68 Ga-PSMA) positron emission tomography (PET)/computed tomography (CT) predicts complete biochemical response from radical prostatectomy and lymph node dissection in intermediate- and high-risk prostate cancer

Abstract

Objective: To determine the value of gallium-68-prostate-specific membrane antigen (⁶⁸ Ga-PSMA)-11 positron emission tomography (PET) /computed tomography (CT) in men with newly diagnosed prostate cancer.

Patients and methods: We analysed results of 140 men with intermediate- and high-risk prostate cancer. All men underwent ⁶⁸ Ga-PSMA-11 PET/CT and multiparametric magnetic resonance imaging (mpMRI) before radical prostatectomy (RP) with extended pelvic lymph node (LN) dissection. For each patient, the clinical and pathological features were recorded. Prostate-specific antigen (PSA) was documented at staging scan, and after RP, at a median (interquartile range) of 110 (49-132) days. A PSA level of ≥0.03 ng/mL was classified as biochemical persistence (BCP). Logistic regression was performed for association of clinical variables and BCP.

Results: In these 140 patients with intermediate- and high-risk prostate cancer, 27.1% had PSMA PET/CT-positive findings in the pelvic LNs. Sensitivity and specificity for detection of LN metastases were 53% and 88% (PSMA PET/CT) and 14% and 99% (mpMRI), respectively. The overall BCP rate was 25.7%. The BCP rate was 16.7% in men who were PSMA PET/CT LN-negative compared to 50% in men who were PSMA PET/CT LN-positive (P < 0.05). The presence of PSMA-positive pelvic LNs was more predictive of BCP after RP than cT-stage, PSA level, and the Gleason score, adjusted for surgical margins status.

Conclusions: ⁶⁸ Ga-PSMA-11 PET/CT is highly predictive of BCP after RP, and should play an important role informing men with intermediate- or high-risk prostate cancer.

Keywords: #PCSM; #ProstateCancer; accuracy; biochemical recurrence; positron emission tomography; prostate-specific membrane antigen; radical prostatectomy.