Médecine Nucléaire | 2021
Detection of primary tumor by 18F-FDG PET/CT in cancer of unknown primary (+ Running poster)
Abstract
Introduction Patients with carcinoma of unknown primary are a diverse and heterogenous group. There are various clinical manifestations and some of the patients could be asymptomatic and diagnosed incidentally. Among numerous imagining techniques, PET/CT seems to be the most suitable for localizing the primary tumor. The sensitivity of PET/CT in detecting primary tumor is 29%–69% according different authors and it is higher comparing to contrast enhanced CT. The purpose of this retrospective study was to estimate the detection ratio of 18F-FDG PET-CT in highlighting the sites of primary tumors in patients with carcinoma of unknown primary. Materials and methods Sixty-seven patients with cancer of unknown primary (39 males, 28 females, the mean age was about 62\xa0years), unsuccessfully investigated with conventional diagnostic procedures and laboratory investigation, were enrolled for 18F-FDG PET-CT whole body imaging. Patients received 370\xa0MBq FDG (10 mCi) intravenously, and whole body images were acquired at 60\xa0min after injection. The images obtained were analyzed with visual and semi-quantitative methods. Results The primary tumor site was correctly identified by 18F-FDG PET/CT in 23 patients (23/67; 34.3%): gastrointestinal tract (n\xa0=\xa06), lung (n\xa0=\xa04), rino/oro-pharynx (n\xa0=\xa04), mammary gland (n\xa0=\xa02), lymphatic system (n\xa0=\xa02), prostate gland (n\xa0=\xa01), thyroid (n\xa0=\xa01), parotid gland (n\xa0=\xa01), bladder (n\xa0=\xa01), and kidney (n\xa0=\xa01). Conclusion Our study suggests that 18F-FDG PET-CT is a useful noninvasive imaging tool to locate the primary tumor in patients with unknown primary malignancies, with high impact in clinical management and plan therapeutic strategies.