Describing Treatment Patterns For Elderly Patients With Intrahepatic Cholangiocarcinoma And Predicting Outcomes By A Prognostic Model

Background&objective:Intrahepatic cholangiocarcinoma(ICC)is the second most common primary malignant tumor of the liver,and its incidence increases with age.With the increased incidence of ICC and the growth of aging population,the management of elderly ICC patients has gradually become a global medical problem.However,elderly patients with ICC are often under-represented in clinical trials,resulting in unclear treatment of this population.The purpose of this study was to explore the treatment pattern and survival outcome of elderly ICC patients,and to construct a reliable prognostic model to individually predict their prognosis,which could provide evidence for the clinical treatment of elderly patients.Methods:Based on the Surveillance,Epidemiology,and End Results(SEER)database,we conducted a retrospective analysis of 1651 elderly patients(≥65 years)diagnosed with ICC between 2004 and 2016,and divided these cases into two age groups(65-74 years and ≥75 years).Treatment patterns in different age groups were analyzed and differences in survival outcomes were compared among patients receiving different therapeutic methods.Logistic regression and Cox proportional hazard models were utilized to analyze the determinants of treatment receipt and prognosis,respectively.According to the selected independent prognostic factors,a nomogram was constructed to predict the survival of elderly ICC patients and compared with the traditional American Joint Committee on Cancer(AJCC)TNM staging system.Finally,in the training cohort,X-tile was used for risk stratification based on the total risk scores,and Kaplan-Meier curve and Log-rank test were applied to assess the survival differences among these risk groups.Results:1.For the whole study population,29.3% received only chemotherapy,26.7%no tumor-directed therapy,19.1% surgery alone,17.5% radiotherapy,and 7.4%surgery plus chemotherapy.Chemotherapy alone remained the most extensive option for patients aged 65-74 years(32.8%),while the largest number of patients aged ≥75years did not accept any cancer therapy(36.4%).2.According to the results of polytomous logistic regression,patients aged ≥75years were less likely to receive treatment compared with the 65-74 years age group.3.Kaplan-Meier survival analysis showed that compared with the age group of65-74 years,patients aged ≥75 years had a worse prognosis.Among patients 66-74 years of age,surgery alone resulted in a median overall survival(OS)of 30 months,surgery combined with chemotherapy 26 months,radiotherapy 17 months,chemotherapy alone 10 months and no therapy 3 months;while among patients ≥75years of age,the median OS was 21,25,14,9 and 4,respectively.4.In the multivariate Cox analysis,age,gender,grade,tumor size,T stage,N stage,M stage,and treatment were all proven to be independent prognostic factors.Based on the above eight prognostic indicators,a prediction model was established to predict the 3-year or 5-year survival probability of elderly patients with ICC.5.The C-indexes of the nomogram were 0.725 and 0.724 for the training and validation cohorts,respectively,indicating the perfect discrimination of the prediction model.6.The calibration curves reflected the good consistency between the survival results predicted by the model and the actual survival results,confirming the good fitting degree of the model.7.The receiver operating characteristic(ROC)curve and decision curve analysis(DCA)displayed that the prediction model had better predictive ability and higher clinical application value than the traditional TNM staging.8.According to the total risk scores(175 points and 253 points),patients were divided into three groups: low-,middle-and high-risk groups.There were significant prognostic differences among these three risk groups on the Kaplan-Meier curve,which meant that the risk classification system produced by this model had a good predictive accuracy.Conclusions:1.Although elderly patients with ICC can benefit from active treatment,the elderly population is relatively conservative in choosing treatments,especially those aged ≥75 years.2.The prognostic model based on the SEER database has high prediction accuracy and clinical applicability.It can more precisely predict the 3-year and5-year survival rate of elderly patients with ICC,which will help clinicians to provide better individualized prognostic assessment and treatment guidance.