Prognostic value of pretreatment primary tumor and regional lymph node necrosis in nasopharyngeal carcinoma with 3DRT

Objective: To investigate the clinical features and prognostic, value of primary tumor and regional lymph node necrosis in nasopharyngeal carcinoma (NPC). Methods: Clinical data were collected from 477 patients newly diagnosed with NPC in our hospital from 2009 to 2013. Pretreatment MRI and CT scans of primary tumor and regional lymph nodes were performed to analyze the clinical features and prognostic value of primary tumor and regional lymph node necrosis after 3DRT. The survival rates wee calculated using the Kaplan-Meier method and analyzed using the log-rank test. Univariate and multivariate prognostic analyses were made by the log-rank test and the Cox model. Results: In the 477 patients, 219 (45.9%) had tumor necrosis and 258 (54.1%) had not. The patients without tumor necrosis had significantly longer median survival time and significantly higher 3-year overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) rates than those with tumor necrosis (40 vs. 37 months, 93.7% vs. 78.2%, 86.7% vs. 63.8%, 96.3% vs. 87.0%, 93.4% vs. 79.7%, all P = 0.000). The univariate analysis showed that tumor necrosis was an important influencing factor for OS, PFS, LRFS, and DMFS rates in patients. T stage, N stage, and clinical stage were correlated with OS, PFS, and DMFS rates in patients (P = 0.000-0.004). The multivariate analysis showed that pretreatment tumor necrosis were predictive factors for all survival in patients with NPC (P = 0.001-0.022), with T stage for LRFS, DMFS (P = 0.016, 0.006) and N stage for PFS (P = 0.000). Conclusions: Patients with pretreatment tumor necrosis are likely to have recurrence or metastasis as well as shorter survival time than those without tumor necrosis. On the basis of T/N stage, identification of the state of tumor necrosis helps clinical physicians to make more reasonable treatment plans and improve the prognosis. (authors)