Evaluation of serious and unsuspected conditions detected in cancer patients undergoing FDG PET/CT

1621 Objectives FDG PET/CT is routinely performed in cancer patients. Because of its wholebody nature, potentially harmful and previously unknown medical or surgical conditions requiring short term medical attention can be discovered on FDG PET/CT. The aim of our study was to assess the frequency and characterize these serious conditions. Methods We retrospectively reviewed reports of all FDG-PET/CT of patients referred for the evaluation of known or suspected cancer from February 27th 2007 to August 27th 2009. Acquisitions were performed on a dedicated PET/CT camera (Discovery ST, GE Medical System). Low-dose CT scan without IV contrast was performed. Unexpected conditions, detected on PET or CT, which needed short-term medical attention due to an increased risk of morbidity or mortality, were included for analysis. Metastases were included only if they had the potential to result in complications. Conditions known prior to PET/CT were excluded. PET/CT images and medical charts of patients included for analysis were reviewed. Results A total of 6864 patients (3359 M, 3505 F, mean age 62,8 y) had 8056 FDG PET/CT during the evaluation period. Main indications were lung, breast, and colorectal cancers. A hundred and four serious unsuspected conditions were found in 103 patients. Conditions were classified into the following categories: inflammatory (n=3, vasculitis, cholecystitis), urological (n=9, acute urinary obstruction, acute renal failure), bony metastases at high risk of fracture (n=39), infections (n=12, pneumonia, discitis, abscess, empyema), neurological (n=8, brain metastasis, spinal cord compression), vascular (n=19, large aneurysm, inferior vena cava perforated by a intravascular filter) and cardiopulmonary (n=14, pericardial effusion, pneumothorax, tracheal invasion). Conclusions 1,5 % of patients undergoing oncological FDG PET/CT presented an unsuspected serious condition at risk for complication requiring urgent or rapid evaluation. These conditions included a wide variety of pathologies in different regions of the body, adding to the complexity of PET/CT interpretation