How PET-CT is Changing the Management of Non-metastatic Castration-resistant Prostate Cancer?: Comment la TEP-TDM...

The aim of this narrative review conducted by the Prostate Cancer Committee of the French Association of Urology (CC-AFU) was to provide an update on the current evidence for the impact of PET/CT in the management of men with non-metastatic castration-resistant prostate cancer (nmCRPC).

This review is based on data available in the literature on PET/CT imaging for staging nmCRPC patients. A PubMed search and narrative review of the data were performed in March 2022. Only articles in French or English were considered.

Current guidelines recommend bone scan and CT scan as standard imaging modalities for staging and follow-up of patients with nmCRPC. Nearly one-third of asymptomatic patients with presumed nmCRPC ultimately have metastatic disease on conventional imaging. Increasing reports have shown that conventional imaging has limited accuracy in detecting metastatic disease in nmCRPC patients, leading to the development of next-generation imaging techniques. In a retrospective study, 18F-choline PET/CT detected distant metastases in 27/58 high-risk nmCRPC patients with prior negative conventional imaging. The implementation of radiolabeled ligands of the prostate-specific membrane antigen (PSMA) PET/CT in staging strategy has resulted in metastasis detection in 45% to 98% of patients with presumptive nmCRPC on conventional imaging. Such an early diagnosis of metastatic CRPC may allow patients to be referred for metastasis-directed therapies (i.e. stereotactic body radiotherapy), aimed at prolonging the efficacy of systemic therapies and improving clinical outcomes. However, current data are not strong enough to recommend this strategy, which must be properly evaluated in clinical trials. Indeed, the use of molecular imaging may lead to inappropriate undertreatment if the second-generation androgen receptor inhibitors (darolutamide, enzalutamide, apalutamide), which prolong life, are not used in the subgroup of patients with high PSA velocity (PSA doubling time <10 months).

Implementation of PSMA-PET/CT in the staging strategy would result in a migration of disease stage to extra-pelvic, M1 disease in at least half of presumed nmCRPC patients. The unprecedented accuracy of PSMA-PET/CT may pave the way for a more personalized treatment strategy. However, no data yet support this strategy for all nmCRPC patients as no oncologic benefit of early detection of M1 disease or MDT has been demonstrated. © 2022 Elsevier Masson SAS. All rights reserved.