Meta-analysis of the diagnostic performance of serum carbohydrate antigen 19-9 for the detection of gallbladder cancer.

Introduction: Carbohydrate antigen 19-9 (CA19-9) is a well-studied tumor marker, yet its diagnostic value for gallbladder cancer remains unclear. The present meta-analysis was conducted to validate the role of serum CA19-9 for the detection of gallbladder cancer.

Methods: A systematic search of digital databases was conducted, complemented by additional hand-searching. Studies that reported serum CA19-9 for the differentiation of gallbladder cancer cases from non-gallbladder cancer controls were considered eligible.

Results: A total of 27 studies involving 4300 subjects were included. The pooled sensitivity, specificity, and area under the curve in diagnosing gallbladder cancer were 0.70 (95% confidence interval (CI): 0.63-0.76), 0.92 (95% CI: 0.88-0.94), and 0.89 (95% CI: 0.86-0.92), respectively. The pooled positive likelihood rate, negative likelihood rate, and diagnostic odds rate were 8.30 (95% CI: 5.84-11.69), 0.33 (95% CI: 0.27-0.41), and 25.13 (95% CI: 5.83-39.89), respectively. Meta-regression analysis revealed that there was significantly lower sensitivity (0.69, 95% CI: 0.61-0.77) and specificity (0.91, 95% CI: 0.87-0.95) when CA19-9 was used for the differentiation of gallbladder cancer cases from benign biliary diseases. A better specificity of 0.93 (95% CI: 0.90-0.96) was reached in the setting of a sample size ≥100.

Conclusions: Serum CA19-9 can be a potential candidate marker for the detection of gallbladder cancer, which maintains moderate sensitivity and good specificity. Attention should be paid to the control type and sample size, which may affect its diagnostic accuracy. Also, results should be interpreted with caution due to significant heterogeneity primarily caused by different thresholds between included studies.