CA 19-9 predicts resectability of pancreatic cancer even in jaundiced patients

Abstract

Background: Surgical resection remains the only curative option for pancreatic adenocarcinoma. Despite recent improvements in medical imaging, unresectability is still often discovered at the time of surgery. It is essential to identify unresectable patients preoperatively to avoid unnecessary surgery. High serum CA 19-9 levels have been suggested as a marker of unresectability but considered inaccurate in patients with hyperbilirubinemia.

Aim of the study: To evaluate CA 19-9 serum levels as a predictor of unresectability of pancreatic adenocarcinomas with a special focus on jaundiced patients.

Methods: All patients presenting with histologically-confirmed pancreatic adenocarcinoma and having serum CA 19-9 levels available prior to any treatment were included in this retrospective study. The relationship between serum concentrations of CA 19-9 and resectability was studied by regression analysis and theROC curves obtained. A cut-off value of CA 19-9 was calculated. In jaundiced patients, a CA 19-9 adjusted for bilirubinemia was also evaluated.

Results: Of the 171 patients included, 49 (29%) were deemed resectable and 122 (71%) unresectable. Altogether, 93 patients (54%) had jaundice. The area under the ROC curve for CA 19-9 as a predictor of resectability was 0.886 (95%CI:[0.832-0.932]); in jaundiced patients it was 0.880 (95% CI [0.798-0.934]. A cut-off in CA 19-9 at 178 UI/mlyielded 85% sensitivity, 81% specificity and 91% positive predictive value for resectability. There was no correlation between the levels of bilirubin and CA 19-9 (r = 0.149).

Conclusion: Serum CA 19-9 is a good predictive marker of unresectability of pancreatic adenocarcinoma, even in jaundiced patients. CA 19-9 levels over 178 UI/ml strongly suggest unresectable disease.

Keywords: CA 19–9; Jaundice; Pancreatic adenocarcinoma; Resectability.