S0083 Risk of Development of Cholangiocarcinoma in Patients with Atypical Cells on Brush Cytology During ERCP for Primary Sclerosing Cholangitis

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a chronic fibro-inflammatory process affecting hepatobiliary system. Reported lifetime incidence of cholangiocarcinoma (CCA) in PSC is 20%. Endoscopic retrograde cholangiography (ERCP) with brush cytology has high specificity but variable sensitivity to detect CCA. Atypical cells are frequently noted on cytology. It is unclear if atypical cells suggest presence of, or increased risk of development of cholangiocarcinoma as compared to patients with normal brush biopsy. METHODS: This is an IRB approved retrospective study looking at adult patients with PSC who received index ERCP with brush cytology at our large tertiary care academic institution from 2005 to 2018. All endoscopies were performed by two experienced endoscopists with more than 20 years of experience. We included patients having normal cells or atypical cells on brush cytology in our study. Demographic and clinical data including CA 19-9, results of imaging, follow up time, presence or development of cholangiocarcinoma if any, were recorded. RESULTS: We identified 210 patients with PSC of which 165 patients without an existing diagnosis of cholangiocarcinoma received index ERCP with brush cytology. Mean age was 43 (18) years and 67% were males. Of the 165 patients, 130 (79%) had normal cells on cytology, 28 (17%) patients had atypical cells on cytology, 1 had low grade dysplasia, and 6 (3.6%) patients were diagnosed with high grade dysplasia/adenocarcinoma. Two (7.1%) of 28 patients with atypical cells were diagnosed with cholangiocarcinoma as compared to 5 (3.8%) of 130 patients with normal cytology (P = 0.61) at a mean follow up of 7.3 (5.5) years. Of the 2 patients with atypical cells on cytology who were diagnosed with cholangiocarcinoma, the first patient was diagnosed within 3 months; this patient had significantly elevated CA 19-9 of 768 ng/ml. The CA 19-9 of all other 27 patients was less than 100 ng/ml. The second patient developed cholangiocarcinoma at 16 years from index ERCP. Twenty-four patients had subsequent repeat ERCP with brush cytology, of which 22 (92%) had turned to normal cytology and 2 (8%) remained atypical cells. CONCLUSION: PSC patients with atypical cells on brush cytology during ERCP and having a normal CA 19-9 are unlikely to harbor cholangiocarcinoma and are at low risk for development of cholangiocarcinoma in the near future. In these patients the atypical cells are likely as a result of inflammation from underlying PSC rather than cholangiocarcinoma.