Comparison of clinical usefulness of serum Ca125 and CA19-9 in pancreatic adenocarcinoma diagnosis: meta-analysis and systematic review of literature.

Abstract Background: Pancreatic adenocarcinoma remains one of the most lethal cancers. This is caused by its late manifestation and lack of extensively available, highly accurate diagnostic tools. The only recommended biomarker CA19-9 proves to be not accurate enough to establish a certain diagnosis. Therefore a standardization of usefulness of other biomarkers is essential. Consequently, our aim was to assess the specificity and sensitivity of Ca125 in comparison with CA19-9 by means of meta-analysis. The systematic review of combined tests (CA19-9+Ca125) was also carried out. Methods: We conducted a systematic search of Medline (via PubMed) and Ovid. After screening of abstracts and the assessment of full-texts, 9 studies (number of patients, n = 1599) were included in the meta-analysis. Hierarchical summary receiver under operator curve (hsROC) model was applied to estimate the diagnostic accuracy. Results: CA19-9 sensitivity and specificity were 0,748 (95%CI 0,676-0,809) and 0,782 (95%CI 0,716-0,836) respectively. These values were estimated on 0,593 (95%CI 0,489-0,69) and 0,754 (95%CI 0,817-0,668) for Ca125. Regarding the heterogeneity of studies we found a strong threshold effect for Ca125 and moderate one for CA19-9. Conclusions: Our meta-analysis did not prove the superiority of Ca125 in diagnosis of pancreatic adenocarcinoma. It should be nevertheless noted that analysed studies are encumbered with high heterogeneity mainly due to threshold effect. Moreover the sparsity of studies precludes accurate analysis of various factors’ influence. Therefore further research into Ca125 is warranted to fully elucidate its usefulness. The review of proposed combined tests shows that although CA19-9+Ca125 models are characterized by higher sensitivity, their usefulness is hampered by inferior specificity to than that of CA19-9 alone.