Image interpretation of 18F-DCFPyL PET/CT imaging

Interpretation of the scans was performed by nuclear medicine physicians in the three hospitals, all of whom have an ample experience with PSMA PET reading (>400 scans). PSMA reporting was performed in accordance with the PROMISE criteria [24]. If at least one metastatic lesion or sign of local recurrence in the prostate/prostatic fossa (miTr) was found, the scan was considered to be positive (i.e., focal and higher uptake of the PSMA tracer compared to the surrounding tissue, not compatible with physiological uptake). Loco-regional lymph node metastases in the true pelvis were classified as miN1. miM1a was defined as lymph node metastatic disease outside the surgical template, whereas lesions that showed increased PSMA expression in the bones or the visceral organs were classified as miM1b and miM1c, respectively. This classification was conform the EAU guidelines [20].