Clinical Relevance of Ratios Derived from Routine Blood-Based Biomarkers in Cholangiocarcinoma: A Retrospective Cohort Study

<i>Background and Objectives:</i> Cholangiocarcinoma (CCA) is an aggressive tumor that originates in the biliary tract and is subdivided anatomically into intrahepatic (iCCA) and extrahepatic (perihilar-pCCA and distal-dCCA). Diagnosis remains challenging, particularly for extrahepatic forms (pCCA and dCCA). We aimed to assess the relation between systemic inflammatory markers-specifically lymphocyte-related ratios-and tumor characteristics in a Romanian cholangiocarcinoma cohort. <i>Materials and Methods:</i> We conducted an exploratory single-center study including adult patients with a confirmed CCA histopathological diagnosis. We excluded patients with an uncertain diagnosis or tumors of the ampulla of Vater or gallbladder. Demographic and clinical data were retrospectively collected from medical records. <i>Results:</i> Tumor localization was the strongest predictor of metastatic disease. The odd of metastasis was 7.3 times higher for iCCA than dCCA and 4.5 times higher for iCCA than pCCA. Although several evaluated inflammatory biomarkers showed statistically significant associations, their clinical relevance was limited. The odds ratios for these biomarkers were characterized by lower bounds near the null value and wide confidence intervals, reflecting considerable patient heterogeneity, model instability, and inconclusive effect sizes. <i>Conclusions:</i> Our findings suggest a potential biological link between systemic inflammation, metastatic spread, and tumor differentiation grade that deserves further investigation using more accurate systemic inflammation biomarkers than those routinely collected.