The role of histopathological and biochemical parameters for predicting metastatic disease on 68Ga‐PSMA‐11 PET in prostate cancer

Background The aim of this study was to evaluate the role of histopathological and biochemical parameters in the prediction of the presence and number of PSMA positive lesions consistent with the metastatic spread of prostate cancer on 68Ga‐PSMA PET images. Methods Biochemical, histopathological and imaging data of 302 prostate cancer patients who underwent 68Ga‐PSMA‐11 PET/CT or PET/MR imaging for primary staging were retrospectively analyzed. Patients were divided into two groups as “PET positive” and “PET negative” according to the presence of pathologic extraprostatic PSMA involvement. “PET positive” patients were additionally divided into two groups: oligometastatic (1‐3 metastatic lesion) and multimetastatic (>3 metastatic lesions). Results The mean age of patients was 66.8 ± 7.6 years. Imaging modality was PET/MR in 223 (73.8%) and PET/CT in 79 (26.2%) of patients. Total PSA, PSA density (PSAD), ALP, and tumor ratio in biopsy specimens were found to be significantly higher in “PET positive” group compared to “PET negative” group and in multimetastatic group compared to oligometastatic group. PET positivity was observed in 3.8% of the low‐intermediate risk groups (ISUP 1‐3 and total PSA ≤ 20 ng/ml and PSAD 20 ng/ml or PSAD ≥ 0.15 ng/ml/cc) with a relative risk of 12 (p