Construction And Validation Of A Nomogram For Predicting Cancer-specific Survival In Patients With Spinal Chordoma

Objective:Chordoma is a very rare type of malignant bone tumor,mostly found in the vertebrae and sacrum.Chordoma is characterized by a high recurrence rate,which makes the survival rate and quality of life of patients unsatisfactory.The overall 5-year survival rate for patients is reported to be only about 50%.The low incidence of spinal chordoma makes it difficult to achieve accurate survival predictions for patients with spinal chordoma.Our goal is to construct and validate a nomogram model for predicting(Cancer-specific survival,CSS)in patients with spinal chordoma.Methods:We collected clinical and follow-up data from a total of 316 patients with spinal chordoma between 1998 and 2015 from the Surveillance,Epidemiology,and End Results(SEER)database.Univariate and multivariate Cox regression analyses were performed to determine independent prognostic factors for patients with spinal chordoma.Based on independent prognostic factors,R software was used to construct a nomogram to predict the CSS of patients with spinal chordoma.The receiver operating characteristic(ROC)curve,area under the curve(AUC),calibration curve,and decision curve analysis(DCA)were used to evaluate the discrimination and clinical usefulness of the nomogram model.Finally,Kaplan-Meier survival curve analysis and log-rank test were used to verify the prognostic value of the nomogram.Results:Through univariate and multivariate Cox regression analysis,we determined that the patient’s primary site,disease stage,histological type,surgery,and age were independent prognostic factors for patients with spinal chordoma.On this basis,a nomogram for predicting CSS in patients with spinal chordoma was constructed.The AUCs for predicting 1-year,3-year,and 5-year CSS in patients with spinal chordoma using nomogram was 0.821,0.856,and 0.920,respectively,in the training cohort and 0.728,0.804,and0.839,respectively,in the validation cohort.Meanwhile,the AUC value of this nomogram is higher compared to the AUC value of the single variable predicted CSS.The calibration curves showed a high agreement between the results predicted by the nomogram and the actual observed results.The DCA of the nomogram further demonstrated that the nomogram model has a high clinical application value.Kaplan-Meier survival curves showed that the prognosis of patients becomes worse as the risk increases.Conclusion:A nomogram was constructed and validated to predict the individual CSS of patients with spinal chordoma.Clinicians can use this nomogram to categorize patients into different risk groups and thus optimize the treatment plan for these patients.