ABSTRACT
Objective To propose a new N staging system for nasopharyngeal carcinoma based on intensity-modulated radiotherapy (IMRT) and Radiation Therapy Oncology Group (RTOG) guidelines for cervical lymph node levels.Methods A retrospective analysis was performed in 324 patients with newly diagnosed nasopharyngeal carcinoma who had no distant metastasis confirmed by pathology and received IMRT in the Department of Radiation Oncology in The First Affiliated Hospital of Guangxi Medical University from January 2010 to December 2011.They were restaged according to the 7thedition of UICC/AJCC staging system for nasopharyngeal carcinoma.The survival rates were estimated using the Kaplan-Meier method and the log-rank test was used for univariate prognostic analysis.The Cox proportional hazards model was used for multivariate prognostic analysis.Results Of 324 patients,269(83.0%) had lymph node metastasis.The median follow-up was 58 months (6-77 months).The 5-year overall survival,disease-free survival,relapse-free survival,and distant metastasis-free survival rates were 84.8%,77.1%,92.7%,and 80.5%,respectively.Univariate and multivariate analyses of patients with positive cervical lymph nodes revealed that retropharyngeal lymph node status,cervical lymph node level,and laterality were evaluated as independent prognostic factors for nasopharyngeal carcinoma.According to the hazard ratio calculated,the N staging system was revised as follows:N0:no regional lymph node metastasis;N1:VⅡ a or/and unilateral levels (I,Ⅱ,Ⅲ,Va) involvement;N2:bilateral levels (I,Ⅱ,Ⅲ,Va) involvement;N3:levels IVa,Vb,and IVb+Vc involvement.Conclusions The proposed N staging system is based on IMRT and RTOG guidelines for lymph node levels and more practical,and can provide highly objective prediction of outcome and guide treatment in nasopharyngeal carcinoma.
ABSTRACT
Objective To establish a new T staging system for nasopharyngeal carcinoma ( NPC) based on magnetic resonances imaging ( MRI) and intensity?modulated radiotherapy ( IMRT) . Methods A retrospective analysis was performed on the clinical data of 608 patients who were newly diagnosed with non?metastatic NPC by MRI and treated with IMRT in our hospital from 2008 to 2010. All patients were staged according to the 7th edition of the UICC/AJCC staging system for NPC. The survival rates were calculated using the Kaplan?Meier method and analyzed using the log?rank test. The Cox regression model was used for multivariate analyses. To deal with the deficiency in the current UICC/AJCC staging system, a new T staging system for NPC was established and systematically evaluated. Results The 5?year follow?up rate was 94?5%. The 5?year overall survival (OS), disease?free survival, local relapse?free survival (LRFS), and distant metastasis?free survival rates were 81?5%, 80?1%, 86?0%, and 81?1%, respectively. The univariate and multivariate analyses showed that the anatomic structures of nasopharynx, parapharyngeal space, and skull base were influencing factors for the OS rate (P=0?000?0?045). New T staging criteria were proposed based on the risk differences and survival curves:stage T1:invasion of the nasopharynx, parapharyngeal space, oropharynx, nasal cavity, skull base, and internal pterygoid muscle;stage T2:invasion of the external pterygoid muscle, paranasal sinus, intracalvarium, infratemporal fossa, and cranial nerves. The proposed T staging system achieved a good separation in both OS and LRFS curves. Conclusions The proposed new T staging system gives an objective prognostic prediction in patients with NPC, which provides an exploratory attempt toward a new clinical staging system for NPC.