[PET/CT and biochemical recurrence of prostate adenocarcinoma: Added value of 68Ga-PSMA-11 when 18F-fluorocholine is non-contributive]

Abstract

Introduction: Since April 201, we have introduced PET/CT using a ligand of prostate-specific membrane antigen labeled with gallium-68 (PSMA-11). We aimed to evaluate its positivity rate and impact in patients presenting biochemical recurrence of prostate cancer whose ¹⁸F-fluorocholine (FCH) PET/CT was non-contributive.

Patients and method: Patients were prospectively included between April and December 2016. PET/CT was performed 60min after injection of 2MBq/kg of body mass of ⁶⁸Ga-PSMA-11. Three anatomical areas were considered: prostatic lodge, pelvic lymph nodes and distant locations. The impact of PSMA-11 PET/CT was assessed by comparing changes in therapeutic strategy decided during multidisciplinary meeting.

Results: Thirty-three patients were included. The mean PSA serum level measured on the month of the PSMA-11 PET/CT was 2,8ng/mL. Twenty-five (76%) PSMA-11 PET/CT were positive, 7 (21%) negative and 1 (3%) equivocal. Of 11 patients whose FCH PET/CT showed equivocal foci, PSMA-11 PET/CT confirmed those foci in 5 cases. Follow-up was available for 18 patients (55%). PSMA-11 PET/CT results led to a change in management in 12 patients (67%).

Conclusion: ⁶⁸Ga-PSMA-11 PET/CT is useful in detecting recurrence of prostate cancer, by identifying residual disease which was not detected on other imaging modalities and by changing management of 2 patients out of 3.

Level of evidence: 5.

Keywords: (18)F-fluorocholine; (68)Ga-PSMA ligand; Biochemical recurrence; Cancer de la prostate; Ligand du PSMA (68)Ga; PET/CT; Prostate cancer; Récidive biologique; TEP/TDM.