Localization of radio-recurrence within the prostate: anti-3-18F-FACBC PET/CT compared with multiparametric MRI using histopathology as reference standard

Abstract

Background

Focal treatment of prostate cancer recurrence is emerging and increases the demand for precision in imaging; pure detection is no longer enough and accurate localization is needed.

Purpose

To investigate the ability of anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid (FACBC) PET/CT to localize radio-recurrences within the prostate, compared to multiparametric magnetic resonance imaging (mpMRI) and with histopathology as the reference standard.

Material and Methods

This prospective salvage focal brachytherapy protocol included 20 patients (mean age = 66 years; age range = 57–72 years) with biochemical recurrence after primary radiotherapy. All patients underwent mpMRI, FACBC PET/CT, prostate biopsies, and bone marrow aspiration. The mean time between mpMRI and FACBC PET/CT was 68 days (range = 5–147 days). Two radiologists and two nuclear medicine physicians independently interpreted MRI and PET. Based on schematic drawings, the quadrant (right, left, anterior, posterior) and the level (apex, mid, base) of tumor recurrence were compared and correlated to histopathology. Written informed consent was obtained from all patients.

Results

PET correctly localized the recurrence in 15 of 20 patients and MRI correctly localized 19 of 20 patients. MRI and PET were concordant for 14 of these 20 patients. There was perfect agreement between the MRI radiologists. Except for one case in which the lesion was only detected by one of the readers, there was also agreement between the nuclear medicine physicians.

Conclusions

FACBC PET/CT detected fewer histological verified radio-recurrences within the prostate than mpMRI. In accordance with previous studies, we found that the limitations of FACBC PET were small tumor amounts and uptake in hyperplastic benign tissue.