Prognostic nomogram for pediatric nasopharyngeal carcinoma in the intensity-modulated radiotherapy era.

Abstract

e18036 Background: There was no prognostic nomogram model exclusive for pediatric nasopharyngeal carcinoma (NPC). This study aimed to establish a nomogram, incorporating clinical characteristics and MRI features, for predicting progression-free survival (PFS) and overall survival (OS) in pediatric NPC. Methods: Children with nonmetastatic NPC treated with intensity-modulated radiotherapy (IMRT) in Sun Yat-sen University cancer center in China between 2004 to 2018 were enrolled and separated in a 3:1 ratio into a training cohort and a validation cohort. The data of the training cohort were analyzed to identify the variables independently associated with PFS and OS, and these variables were used to construct the prognostic nomogram. The predictive accuracy and discriminative capability of the nomogram were evaluated by the calibration curve and the concordance index (C-index). The nomogram was validated in the validation cohort. Results: A total of 200 patients were enrolled: 152 in the training cohort and 48 in the validation cohort. Age, serum lactate dehydrogenase level, and invasion of the clivus were the independent prognostic factors for PFS in the training cohort. The C-index of the nomogram constructed using these variables was 0.86. The calibration curve showed consistency between the nomogram prediction and the actual observation for 5-, 6- and 7-year PFS. In the validation cohort, the C-index of the nomogram was 0.64, and the calibration curve showed good consistency between the nomogram and actual observation for 5-, 6- and 7-year PFS. For OS, no independent prognostic factors were identified. Conclusions: The prognostic nomogram could be a useful tool for predicting PFS in pediatric NPC patients treated with IMRT.