Levels of pretreatment serum lipids predict responses to PD-1 inhibitor treatment in advanced intrahepatic cholangiocarcinoma

Background: It has been identified that serum lipids can be used as prognostic biomarkers in several types of cancer and are associated with patient survival. We aimed to clarify the prognostic value of the serum lipids and to establish a novel effective nomogram for overall survival (OS) in intrahepatic cholangiocarcinoma (iCCA) patients receiving anti-PD1 therapy.Methods: Pretreatment serum lipids were retrospectively analyzed for prognostic value, including apolipoprotein B (APOB), apolipoproteinA-1 (APOA1), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG), which were assessed for prediction accuracy using Kaplan-Meier survival curves and time-dependent receiver operating characteristic (ROC). Cox regression analysis with univariate and multivariate factors was used to identify prognostic factors predictive of OS, and prognostic nomograms were constructed.Results: All the serum lipids showed good discriminatory ability in terms of OS (all P < 0.05), the higher the lipid levels, the better the prognosis, while APOA1 and TG were remarkable independent predictors for OS in multivariate analysis (hazard ratio, 2.177,2.035; confidence interval, 1.393-3.402, 1.184-3.498; P = 0.001, P = 0.01). Four (CA19-9, APOA1, tumor number and TG) independent prognostic factors were chosen to generate the nomogram for OS. The area under the ROC curve at 1-year and 2-year consistently demonstrated that the pre-dictive value of the nomogram was superior to serum lipids.Conclusion: In our study, serum lipid levels were used as a prognostic nomogram in the prediction of anti-PD-1 therapy efficacy in patients with iCCA.