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.

Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is a modern imaging tool used in the diagnosis of prostate cancer (PCa). Approximately 10% of patients who underwent PSMA PET/CT have a biopsy-proven, primary PCa without PSMA expression on PET/CT (non-PSMA_PET-expressing PCa), according to a recent systematic review[1]. However, the definition of non-PSMA_PET-expression in these studies was poorly defined and no immunohistochemical studies for confirmation of PSMA protein expression were performed. The aim of this retrospective study was to report the prevalence, characteristics, and immunohistochemical assessment of non-PSMA_PET-expressing hormone-sensitive PCa in a cohort of 362 patients who underwent PSMA PET/CT and robot-assisted radical prostatectomy (RARP).

Objectives: To construct and externally calibrate a predictive model for early biochemical recurrence (BCR) after radical prostatectomy (RP) incorporating clinical and modern imaging characteristics of the primary tumour. Patients and Methods: Patients who underwent RP following multiparametric magnetic resonance imaging, prostate biopsy and prostate‐specific membrane antigen‐positron emission tomography/computed tomography (PSMA‐PET/CT), from two centres in Australia and the Netherlands. The primary outcome was biochemical recurrence‐free survival (BRFS), where BCR was defined as a rising PSA level of ≥0.2 ng/mL or initiation of postoperative treatment per clinician discretion. Proportional hazards models to predict time to event were developed in the Australian sample using relevant pre‐ and post‐surgical parameters and primary tumour maximum standardised uptake value (SUV _max ) on diagnostic PSMA‐PET/CT. Calibration was assessed in an external dataset from the Netherlands with the same inclusion criteria. Results: Data from 846 patients were used to develop the models. Tumour SUV _max was associated with worse predicted 3‐year BRFS for both pre‐ and post‐surgical models. SUV _max change from 4 to 16 lessened the predicted 3‐year BRFS from 66% to 42% for a patient aged 65 years with typical pre‐surgical parameters (PSA level 8 ng/mL, Prostate Imaging‐Reporting and Data System score 4/5 and biopsy Gleason score ≥4 + 5). Considering post‐surgical variables, a patient with the same age and PSA level but pathological stage pT3a, RP Gleason score ≥4 + 5 and negative margins, SUV _max change from 4 to 16 lessened the predicted 3‐year BRFS from 76% to 61%. Calibration on an external sample ( n = 464) showed reasonable performance; however, a tendency to overestimate survival in patients with good prognostic factors was observed. Conclusion: Tumour SUV _max on diagnostic PSMA‐PET/CT has utility additional to commonly recognised variables for prediction of BRFS after RP.