A Nomogram Predicting Recurrence and Guiding Adjuvant Radiation for Thymic Carcinoma After Resection

Background. Resection is an effective treatment for thymic carcinoma. We aimed to develop a nomogram for postoperative prediction of recurrence-free survival for patients with thymic carcinoma and guide adjuvant radiotherapy. Methods. A total of 198 patients who underwent surgery were divided into training cohort (n = 152) and validation cohort (n= 46). Clinicopathologic features and independent factors for postoperative recurrence were analyzed. A predictive nomogram was developed based on the prognostic factors. Discrimination and predictive accuracy of the model were measured using the concordance index (C-index), calibration curves, and validation study. Results. The overall 1-, 3-, and 5-year recurrence rate of 198 patients was 7.6%, 27.9%, and 39.9%, respectively. Independent predictors of recurrence-free survival on multivariate analysis were incorporated into the nomogram. Calibration curves for the probability of 1-, 3-, and 5-year recurrence-free survival fitted well. The C-index of the nomogram for predicting recurrence-free survival was 0.862 (95% confidence interval: 0.804 to 0.919). Internal validation supported the results optimally. Adjuvant radiotherapy was effective for patients with a total score greater than 208. Conclusions. Our nomogram for predicting recurrencefree survival had good performance. Adjuvant radiotherapy should be recommended for patients with a total score greater than 208. (C) 2018 by The Society of Thoracic Surgeons