Monitoring dominant strictures in primary sclerosing cholangitis with brush cytology and FDG-PET

Abstract

Despite a high risk of cholangiocellular adenocarcinoma (CCA) it is unclear how surveillance of patients with primary sclerosing cholangitis (PSC) should be performed. We evaluated a follow-up algorithm of brush cytology and positron emission tomography/computed tomography with [(18)F] fluorodeoxyglucose ([(18)F]FDG-PET/CT), measured as maximum standardized uptake values, normalized to the liver background (SUVmax/liver) at 180 min, in PSC patients with dominant bile duct strictures. Brush cytology with high grade dysplasia (HGD) was detected in 12/70 patients (17%), yielding a diagnostic sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 56%, 89%, 75%, and 88%, respectively. Preemptive liver transplantations due to repeated HGD before manifest CCA were performed in six patients. Receiver operating characteristic (ROC) analysis of [(18)F]FDG uptake showed that a SUVmax/liver quotient of 3.3 was able to discriminate between CCA and non-malignant disease with a sensitivity, specificity, PPV and NPV for CCA of 89%, 92%, 62%, 98%, respectively. A SUVmax/liver >3.3 detected CCA in 8/9 patients whereas a quotient <2.4 excluded CCA. Combining brush cytology and quantitative [(18)F]FDG-PET/CT yielded a sensitivity for HGD and/or CCA of 100% and a specificity of 88%. Early detection of HGD before manifest CCA is feasible with repeated brush cytology and may allow for preemptive liver transplantation. [(18)F]FDG-PET/CT has a high sensitivity for manifest CCA and a negative scan indicates a non-malignant state of the disease. Brush cytology and [(18)F]FDG-PET/CT are complementary in monitoring and managing PSC patients with dominant strictures.