PSMA-Ligand Uptake Can Serve as a Novel Biomarker in Primary Prostate Cancer to Predict Outcome After Radical Prostatectomy

Abstract

BackgroundThe prostate-specific membrane antigen (PSMA) is a relevant target in prostate cancer and immunohistochemistry studies showed associations with outcome. PSMA-ligand positron emission tomography (PET) is increasingly used for primary prostate cancer staging and the molecular imaging TNM classification (miTNM) standardizes its reporting. We aimed to investigate the potential of PET-imaging to serve as a noninvasive imaging biomarker to predict disease outcome in primary prostate cancer after radical prostatectomy (RP).MethodsIn this retrospective analysis, 186 primary prostate cancer patients treated with RP who had undergone a 68Ga-PSMA-11 PET up to three months prior to the surgery were included. Maximum standardized uptake value (SUVmax), SUVmean, tumor volume (TV) and total lesion (TL) were collected from PET-imaging. Moreover, clinicopathological information, including age, serum prostate-specific antigen (PSA) level, and pathological characteristics were assessed for disease outcome prediction. A stage group system for PET-imaging findings based on the miTNM framework was developed. ResultsAt a median follow-up after RP of 38 months (interquartile range (IQR): 22-53), biochemical recurrence (BCR) was observed in 58 patients during the follow-up period. A significant association between a positive surgical margin and miN status (miN1 vs. miN0, odds ratio (OR): 5.428, p=0.004) was detected. miT status (miT≥3a vs. miT<3, OR: 2.696, p=0.003) was identified as an independent predictor for Gleason score (GS)≥8. Multivariate Cox regression analysis indicated that PSA level (hazard ratio (HR): 1.024, p=0.014), advanced GS (GS≥8 vs. GS<8, HR: 3.253, p<0.001) and miT status (miT≥3a vs. miT<3, HR: 1.941, p=0.035) were independent predictors for BCR. For stage I disease as determined by PET-imaging a shorter BCR-free survival was observed in the patients with higher SUVmax (IA vs. IB stage, log-rank, p=0.022).ConclusionPreoperative miTNM classification from 68Ga-PSMA-11 PET correlates with postoperative GS, surgical margin status and time to BCR. The association between miTNM staging and outcome proposes 68Ga-PSMA-11 PET as a novel non-invasive imaging biomarker and potentially serves for ancillary pre-treatment stratification. Prospective studies with larger cohort are necessary to fully determine its use including primary prostate cancer patients with different treatments and risk categories and late-stage patients.

Standardised uptake values as determined on prostate‐specific membrane antigen positron emission tomography/computed tomography is associated with oncological outcomes in patients with prostate cancer

“…In a study by Wang et al . [28], that studied 195 patients receiving a 68 Ga‐PSMA‐11‐PET/CT for initial staging before RARP, an association was reported between SUV max and surgical margin status on univariate analysis ( P = 0.04). The SUV max was not found to be an independent variable for surgical margin status when assessed along other imaging parameters such as tumour volume, miN status, miT stage.…”