Influence of tumor necrosis on treatment sensitivity and long-term survival in nasopharyngeal carcinoma

•Tumor necrosis served as a predictor of treatment sensitivity and poor prognosis in patients with nasopharyngeal carcinoma (NPC).•Lymph node necrosis significantly improved the prognostic value of the current N classification criteria of NPC.•Patients with tumor necrosis might require effective strengthening treatment such as with radio chemotherapy sensitizers. To assess the impact of tumor necrosis on treatment sensitivity and long-term survival in patients with nasopharyngeal carcinoma (NPC) treated using intensity-modulated radiation therapy (IMRT). In total, 757 patients with non-metastatic, histologically confirmed NPC were retrospectively examined. All patients were treated using IMRT; 93.7% patients with stage T3-T4/N1-N3 disease also received cisplatin-based chemotherapy. The incidence rates of tumor necrosis in primary tumor, retropharyngeal lymph nodes, neck lymph nodes, and total tumor were 2%, 17.7%, 21.5%, and 31.4%. Overall, 40.8% patients with necrosis of the total tumor achieved complete response (CR) and 54.7% patients without tumor necrosis achieved CR at the end of treatment (χ2 = 12.728, P