| BACKGROUD & OBJECTIVE:Nasopharyngeal carcinoma(NPC)is one of the most common malignant tumors in the southern China and especially in Guang dong and Guang xi.NPC with local recurrence plays an important role in the definition of radiotherapy area,clinical staging and prognosis.In the past ten years,Intensity modulated radiation therapy(IMRT)has gradually replaced regular two-dimensional radiotherapy(2D-RT)and become a mainstream treatment for NPC.However,The 7th edition UICC/AJCC T staging is mainly based on conventional clinical examination of 2DRT,and fails to reflect the influence of innovation in diagnosis and therapy on staging.So this study was designed evaluate the prognostic value of NPCs with different structures including nasopharynx,nasal cavity,oropharynx,parapharyngeal space,skull base,internal pterygoid muscle,external pterygoid muscle,paranasal sinus,orbit,cranial nerves and intracalvarium based on MRI,who treated with IMRT.Thus,it may establish a new T staging system and more adapt to IMRT,and provide the basis for clinical treatment and research.Methods: A retrospective review of 608 patients who were newly diagnosed NPC and without distant metastasis between January 2008 and March 2010 at our hospital.According to the 7th edition UICC/AJCC staging system nasopharyngeal carcinoma(NPC),magnetic resonance imaging to review all of the patients,and combination with the related clinical data staging.The Kaplan-Meier method to calculate various survival rate,The differences were compared with the Log-rank test,The Cox model was used for multivariate prognostic analysis;Analysis the insufficiency of the 7th edition UICC/AJCC staging system in predicting the prognosis of NPCs who accepted intensity-modulated radiotherapy,To establish a new T staging system for NPC based on IMRT.According to the principle of staging system,the prognostic value including the risk differece,the distribution balance and the survival prediction were adopted to evaluate the recommend T staging system.Results: The 5-year follow-up rate was 94.5%.the 5 years disease-free survival rate(DFS)was 80.1%,relapse-free survival rate(LRFS)was 86.0%,no distant metastasis survival rate(DMFS)was 81.1%,the 5 years Overall survival rate(OS)was 81.5%.According to the 7th edition UICC/AJCC staging system,infringement of the surrounding structure distribution proportion is as follows:the extents of primary disease invasion were nasopharynx 100%(608/608),nasal cavity 25.6%(209/608),parapharyngeal space 82.4%(501/608),oropharynx 17.6%(107/608),skull base 72.2%(439/608),internal pterygoid muscle 65.5%(398/608),external pterygoid muscle 32.0%(195/608),paranasal sinus 23.8%(145/608),orbit 10.5%(94/608),cranial nerves 23.4%(142/608)and intracalvarium 16.7%(102/608),respectively.According to univariate and multivariate analysis showed that the invasion of nasal cavity,parapharyngeal space,oropharynx,skull base,internal pterygoid muscle,external pterygoid muscle,paranasal sinus,orbit,cranial nerves and intracalvarium were the independent prognostic factors for NPCs(P < 0.05).According to the risk differences and survival curve analysis,it is suggested that based on MRI and IMRT of NPC,A recommended new clinical T stage standards for: T1(nasopharynx,nasal cavity,parapharyngeal space,oropharynx,skull base and internal pterygoid muscle)and T2(external pterygoid muscle,paranasal sinus,orbit,cranial nerves and intracalvarium).Compared to the 7th UICC/AJCC staging system,our recommend T staging system with greatly risk difference and distribution balance,the survival curves of OS and LRFS were in good separation.Conclusion : Our recommend new T staging system based on magnetic resonance imaging and intensity-modulated radiotherapy,it reflect the most advanced mode of diagnosis and treatment for NPCs,and could more objectively and accurately predict the NPC's prognosis,can be used as a new exploratory attempt in the next revisions of staging system. |
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