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

Abstract

Objectives To investigate the association between intraprostatic, intratumoral maximum standardised uptake values (SUV max ) on prostate‐specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in patients with prostate cancer (PCa) prior to robot‐assisted radical prostatectomy (RARP) and pathology outcomes, including pathological International Society of Urological Pathology score (pISUP) and lymph node (LN) status (pN0/pN1). Patients and Methods A bi‐centric, secondary analysis of two previous, prospective cohort studies was performed in 318 patients with biopsy confirmed PCa and who were scheduled for RARP. Before surgery, patients received a PSMA PET/CT with either 68 Ga‐PSMA‐11 (59% of the patients) or 18 F‐PSMA (DCFPyL; 41%) as radiotracer. PET/CT images were analysed both visually and semi‐quantitatively by measuring the SUV max of the most intense suspect lesion in the prostate. The association between the SUV max of the primary tumour and pre‐ and postoperative variables was analysed. Results The SUV max was associated with clinical and biopsy preoperative variables, as well as with pISUP score and pathological tumour stage. Patients with a pISUP of ≤2 showed significantly lower SUV max compared to patients with a pISUP of >2 for both tracers (SUV max 18 F‐PSMA: median 5.1 vs 9.6, P = 0.002; SUV max 68 Ga‐PSMA‐11: 6.6 vs 8.6, P = 0.003). Moreover, patients with pN1 had significantly higher median SUV max than those with pN0/pNx for both tracers (SUV max 18 F‐PSMA: 7.9 vs 12.3, P = 0.04; SUV max 68 Ga‐PSMA‐11: 7.6 vs 12.0, P < 0.001). On multivariable logistic regression analysis, the intraprostatic SUV max was an independent predictor of pN1 for both 68 Ga‐PSMA‐11 (per doubling: odds ratio [OR] 1.96, 95% confidence interval [CI] 1.27–3.01)) and 18 F‐PSMA (per doubling: OR 1.79, 95% CI 1.06–3.03). Conclusion Intraprostatic, intratumoral PSMA intensity on PET/CT, as semi‐quantitatively expressed by SUV max , may be a valuable innovative biomarker in patients with localised PCa, as it is highly associated with known conventional prognostic factors, such as pISUP and LN status.