Unusual uptakes on 18F-fluorocholine positron emission tomography/computed tomography (PET/CT): a retrospective study of 368 prostate cancer patients referred for a biochemical recurrence or an initial staging

Background: F-18-fluorocholine positron emission tomography/computed tomography (F-choline PET/ CT) is considered a cornerstone in the staging and restaging of patients with prostate cancer (PCa). The aim of this study was to retrospectively assess unusual uptakes in patients who underwent a F-choline PET/CT for the initial staging or for the restaging of a relapsing PCa. Methods: Three hundred and sixty-eight PCa patients were staged or restaged using F-choline PET/CT. Unusual uptakes were defined as uptakes occurring outside the usual paths of diffusion of PCa or as uptake in bone with a clear morphological evidence of nonmetastatic lesion. Results: We found unusual uptakes in 47/368 patients (12.8%). Among them, 41/47 presented with benign F-choline uptake, usually within lymph nodes, due to inflammatory processes (22/47). Other benign processes were found in: thyroid (3/47), adrenal gland (3/47), brain (2/47), liver (1/47), bowel (3/47), frontal sinus (1/47), lungs (4/47), parotid gland (1/47) and bone (1/47). The six remaining patients presented with a second cancer, including lymphoma (1/47), non-small cell lung cancer (4/47) and neuroendocrine tumor (1/47). Conclusions: unusual uptakes on F-choline PET/CT are quite frequent and should be explored since they may correspond to non-PCa.

Automated summary

Unusual uptakes on F-choline PET/CT are relatively common in PCa patients, with majority being benign uptake related to inflammatory processes in lymph nodes. Other benign processes and second cancers were also detected, highlighting the importance of further investigation for non-PCa causes.