Hyponatremia is a Predictor of Clinical Outcome for Resected Biliary Tract Cancers: A Retrospective Single-Center Study

Introduction Biliary tract cancers (BTC) include both gallbladder cancer and cholangiocarcinoma, both of which have a poor prognosis. The aim of our study was to evaluate the main clinical prognostic factors in this setting and to assess their impact on overall survival (OS). Methods We retrospectively analyzed data collected on 64 patients with BTC who underwent surgery with radical intent at our institution. OS was estimated using the Kaplan–Meier method. The Cox regression model was used to perform univariate and multivariate analyses. Results Preoperative hyponatremia was found to be an independent prognostic factor that correlated negatively with prognosis, with hyponatremic patients having a poor OS compared to the group of patients with normal serum sodium levels (9.44 vs. 15.47 months; p = 0.0215). In addition, high preoperative values for carbohydrate antigen 19-9 (Ca19.9), a tumor marker for some gastrointestinal cancers, and lactate dehydrogenase (LDH) were found to be prognostic factors for a significant reduction in OS (Ca19-9: 7.14 vs. 24.22 months, p = 0.0088; LDH: 1.70 vs. 15.47 months, p = 0.0384). Conclusion Identification of these prognostic factors may support strategies to identify, in clinical practice, those subgroups of patients with a favorable or unfavorable prognosis before surgical treatment and, therefore, to guide therapeutic choices. In particular, to our knowledge, this is the first report of the prognostic role of serum sodium level in BTC. Early detection and careful monitoring of hyponatremia and supportive therapy can help to improve the treatment and prognosis of BTC.