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.