A new staging system for nasopharyngeal carcinoma based on intensity-modulated radiation therapy (IMRT).

Objective: This study is to establish a new staging system for nasopharyngeal carcinoma (NPC) based on the magnetic resonance imaging (MRI) and intensity-modulated radiation therapy (IMRT).

Methods: Totally 492 patients with nasopharyngeal carcinoma were included in this study. These patients were diagnosed by pathological detection (without distant metastasis) and underwent the initial treatment of IMRT. These patients were subjected to the staging with the International Union against Cancer/American Joint Committee on Cancer (UICC/AJCC) staging system. Survival rates were calculated by the Kaplan-Meier method. Log-rank test was used to calculate the single factor prognosis, and the COX risk model was used to analyze the multivariate prognosis.

Results: In these 492 patients, according to our recommended new T and N staging criteria, there were 290 cases of T1 and 202 cases of T2; there were 64 cases of N0, 159 cases of N1, 226 cases of N2, and 43 cases of N3. Univariate and multivariate analyses showed that the T and N staging combination parameters were independent prognostic factors, which affected the overall survival rates and tumor-free survival rates. According to risk difference and survival curve distribution, the following new clinical staging criteria were established: stage I (T1N0M0), stage II (T1N1M0 and T2N0M0), stage III (T1N2M0 and T2N1-2M0), stage IVa (T1-2N3M0), and stage IVb (TxNxM1).

Conclusion: A new staging system for NPC based on MRI and IMRT has been recommended, which provides valuable evidence for disease treatment and prognosis prediction.