Accuracy of FDG-PET/CT and paraneoplastic antibodies in diagnosing cancer in paraneoplastic neurological syndromes

Abstract

ObjectiveThere is still no consensus about whether to perform PET/CT to detect carcinoma in paraneoplastic neurological syndromes (PNS) in patients with or without antibodies. The aim of this study is to determine the diagnostic accuracy of PET/CT and antibodies in patients with PNS. Material and MethodsA retrospective study was conducted on patients with clinically suspected PNS between 2008 and 2013. The association between histopathological findings, paraneoplastic antibodies, and PET/CT findings were evaluated. Sensitivity and specificity for the detection of underlying malignancy were calculated for PET/CT and paraneoplastic antibodies. ResultsA total of 42 patients were analyzed. Of these 42 patients, 32 (75%) had a classical PNS, 6 (14%) had positive PET/CT findings, and 34 were tested for the presence of antibodies (anti-Hu Ab, anti-Yo Ab, and anti-Ri Ab). Twenty one of 34 patients had positive antibodies. Of the 6 patients with positive PET/CT findings, 6 had positive histopathological results. Among 21 patients with positive biomarkers, carcinoma was confirmed only in 5 patients. One patient with negative antibodies, but positive PET/CT findings, was diagnosed with a tumor. Gastric carcinoma was detected in 1 patient with negative PET/CT findings and antibodies during follow-up. Based on the results, PET/CT was found to have 85.71% sensitivity, 100% specificity, 100% positive and 97.22% negative predictive values in the detection of tumors. ConclusionPET/CT has a certain diagnostic accuracy for detecting underlying malignancy in patients with PNS, regardless of the presence of paraneoplastic antibodies.