Predictors of prostate bed recurrence on magnetic resonance imaging in patients with rising prostate-specific antigen after radical prostatectomy

Pathological predictors of 18 F-DCFPyL prostate-specific membrane antigen-positive recurrence after radical prostatectomy

Objectives

To assess the correlation of pathological radical prostatectomy (RP) specimen features and prostate‐specific antigen (PSA) characteristics to imaging findings on subsequent ¹⁸F‐DCFPyL positron emission tomography/computed tomography (PET/CT) in patients with biochemical failure (BF).

Patients and Methods

Retrospective analysis of combined ¹⁸F‐DCFPyL PET/CT database of patients from centres in Australia and New Zealand was performed. A total of 205 patients presenting with BF after RP were included in this study. Imaging findings on ¹⁸F‐DCFPyL PET/CT were recorded and correlated with the PSA characteristics at BF and pathological features of the original tumour.

Results

Of the 205 patients, 120 (58.5%) had evidence of abnormal prostate‐specific membrane antigen (PSMA) expression compatible with recurrent prostate cancer. Increasing PSA velocity (P = 0.01), International Society of Urological Pathology (ISUP) Grade Group (P = 0.02), lymphovascular invasion (P = 0.05) and nodal positivity (P = 0.02) at the time of RP were more likely to demonstrate PSMA positivity. Multivariable logistic regression revealed a higher PSA level prior to PSMA PET/CT (P < 0.01), adjuvant radiotherapy (P = 0.09), Gleason score ≥8 (P < 0.01) and nodal positivity (P = 0.05) were all predictive of PSMA positivity.

Conclusion

¹⁸F‐DCFPyL PET/CT positivity, both generally and site specific, correlates with PSA and RP pathological factors. Our results echo cohorts focussing on post‐RP patients, those imaged with ⁶⁸Ga‐PSMA and those concerning biochemical persistence. Nomograms that include risk factors for ‘PSMA‐positive recurrence’ in the BF population may increase the catchment of patients with disease confined to the prostate bed or pelvis who have a greater probability of prolonged disease‐free survival.