The Role of Serial Serum Carbohydrate Antigen 19‐9 Surveillance to Detect Recurrences after Curative Resection for Gallbladder Carcinoma

ABSTRACT Background Gallbladder cancer (GBC) is the most common biliary tract malignancy with aggressive biology and poor outcomes. Early detection of recurrence after curative resection is crucial to enable timely systemic therapy. This study evaluates role of Carbohydrate Antigen 19‐9 (CA 19‐9) surveillance in detecting recurrence after radical surgery for GBC. Material and Methods Retrospective analysis of a prospectively maintained database was conducted at Tata Memorial Hospital, India, between 2010 and 2024. Patients undergoing curative‐intent resection for GBC were included. Postoperative CA 19‐9 trends, including first elevated value and serial rise were analyzed to detect recurrence. Results A total of 813 patients were analyzed; 327 (40.2%) developed recurrence. Among them, 210 (64.2%) had a postoperative CA19‐9 rise. Fifty‐three patients had CA 19‐9 elevation without clinico‐radiological recurrence. A first raised CA 19‐9 value (> 37 U/mL) predicted recurrence with 64.5% sensitivity, 89.3% specificity (AUC = 0.681). A serial rise in CA 19‐9 value yielded 45.6% sensitivity and 95.3% specificity. The median duration between first raised CA 19‐9 value and radiological detection of recurrence was 5.4 weeks. Conclusions Serum CA 19‐9 surveillance detects early recurrences in resected GBCs with modest sensitivity and specificity. Serial rise in CA 19‐9 should prompt more detailed investigations to detect recurrence.