Nomograms for predicting survival outcomes in intensity-modulated radiotherapy era of nasopharyngeal carcinoma: A study based on Epstein-Barr virus DNA biological responses.

Abstract

Treatment of nasopharyngeal carcinoma (NPC) is evolving toward Intensity-modulated radiotherapy (IMRT) era, which requires patient-specific reestimation of survival outcomes in modern health care. A total of 488 detectable pre-treatment Epstein-Barr virus (EBV) DNA patients (stage II-IVa) treated with induction chemotherapy (IC) and IMRT were examined (training set, n = 325; validation set, n = 163). Concurrent chemotherapy (CC) was still an independent prognosticator for overall survival (OS) and progression-free survival (PFS). Both nomograms included age, T classification, N classification, post-IC EBV DNA, and CC. Predictions correlated well with observed 3-/5-year OS and PFS. The concordance index was 0.776 (95% confidence interval (CI) 0.69-0.86) for OS and 0.742 (95% CI 0.65-0.83) for PFS in the validation cohort. The nomograms can successfully classify patients into low- and high-risk groups. The validated nomograms provided useful prediction of OS and PFS for detectable pre-treatment EBV DNA patients with NPC in IMRT era.