Nomogram to predict thymoma prognosis: A population‐based study of 1312 cases

BACKGROUND: A thymoma is a common cancer within the anterior mediastinum; however, the prognostic characteristics have not been established. The aim of this study was to identify the prognostic factors and develop a nomogram for the prognostic prediction of patients with thymoma based on data from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Patients with thymomas diagnosed between 1983 and 2014 were selected. Overall survival (OS) was estimated using the Kaplan–Meier method with the log‐rank test. Univariate and multivariate Cox proportional hazards regression analyses were performed to identify the independent prognostic factors, from which a nomogram for thymomas was created. External validation of the nomogram was performed using data from our center. RESULTS: A total of 1312 patients with thymomas were enrolled. Age, tumor size, Masaoka–Koga stage, chemotherapy administered, and surgery type were independent prognostic factors for OS. A nomogram for OS was formulated based on the independent prognostic factors and validated using an internal bootstrap resampling approach, which showed that the nomogram exhibited a sufficient level of discrimination according to the C‐index in training (0.713, 95% confidence interval 0.685–0.741) and (0.746, 95% confidence interval 0.625–0.867) validation cohorts. CONCLUSION: Several prognostic factors for thymomas were identified. The nomogram developed in this study accurately predicted the 5‐year and 10‐year OS rates of patients with thymomas based on individual characteristics. Risk stratification using the survival nomogram could optimize individual therapy and follow‐up.