Contemporary Update on Prognostic Nomograms for Endemic Nasopharyngeal Carcinoma: Real-World Results from a Big-Data Intelligence Platform-Based Analysis

Background: To investigate the survival outcomes and update effective prognostic nomograms of nasopharyngeal carcinoma (NPC) in an endemic area. Methods: A retrospective cohort of 10126 patients who underwent radical intensity-modulated radiotherapy (IMRT) at Sun Yat-sen University Cancer Center (SYSUCC) from April 2009 to December 2015. We assigned patients into a training cohort (SYSUCC-A; n=6751) and an internal validation cohort (SYSUCC-B; n=3375) based on computer-generated random numbers. Patients collected from Wuzhou Red Cross Hospital (WZRCH) between February 2012 and July 2015 were used as the independent external validation cohort (WZRCH; n=450). Concordance index (C-index) was used to determine predictive accuracy and discriminative ability of the nomogram. Overall survival (OS) was the primary endpoint. Secondary endpoints consisted of local relapse-free survival (LRFS), regional relapse-free survival (RRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS). All statistical tests were two-sided. Findings: The three- and five-year OS, LRFS, RRFS, DMFS, and DFS rates were 92.3% and 86.5%, 95.4% and 93.4%, 96.0% and 94.3%, 89.5% and 87.0%, and 83.4% and 78.4%, respectively. Gender, age, T stage, and N stage were identified independent risk factors that predicted OS, which were all assembled into the nomogram and derived from multivariable analysis of the SYSUCC-A cohort. The nomogram c-index for OS was 0.725 (95% CI, 0.679-0.772). Calibration curve for probability of death revealed the nomogram-based predictions were in good agreement with actual observations. C-index of the nomograms for LRFS, RRFS, DMFS, and DFS were 0.684 (95% CI, 0.611-0.756), 0.650 (95% CI, 0.571-0.728), 0.680 (95% CI, 0.630-0.731), and 0.669 (95% CI, 0.629-0.710), respectively. All results were confirmed in the validation cohorts. Interpretation: Patients with NPC had satisfactory locoregional survival outcomes undergoing IMRT in an endemic area, and distant metastasis predominates as the pattern of disease relapse. These validated nomograms could serve as useful tool for predicting survival outcomes and providing patient counseling. Funding Statement: This work was supported by the Special Support Program of Sun Yat-sen University Cancer Center (16zxtzlc06), the Health & Medical Collaborative Innovation Project of Guangzhou City, China (201604020003), the Natural Science Foundation of Guang Dong Province (No. 2017A030312003), Health & Medical Collaborative Innovation Project of Guangzhou City, China (201803040003), the Innovation Team Development Plan of the Ministry of Education (No. IRT_17R110), the Overseas Expertise Introduction Project for Discipline Innovation (111 Project, B14035) and the National Natural Science Foundation of China (No. 81802707). Declaration of Interests: The authors declare no potential conflicts of interest. Ethics Approval Statement: All patients provided informed consent, and consent waiver for the rest of the cohort was approved by the respective ethical review boards. Patients’ clinical and demographic information were anonymized before analysis.