New suggestion for clinical downstaging of nasopharyngeal carcinoma in the era of intensity-modulated radiotherapy / 中华放射肿瘤学杂志

ABSTRACT

Objective To propose a new suggestion for the clinical downstaging of nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiotherapy (IMRT) without changing the current T,N,and M staging system.Methods We reviewed the records of 536 NPC patients treated in Sun Yat-Sen University Cancer Center from January 2002 to December 2006.The Kaplan-Meier method was used to calculate the disease-specific survival (DSS) rate,and the log-rank test was used for survival difference analysis.The Cox regression model was used to calculate the hazard ratio (HR) of each subset.ResultsAccording to the 7th edition of UICC/AJCC staging system,the 5-year DSS rates of stage Ⅰ-Ⅲ patients (except T3N2M0) were all more than 85%(P>0.05),those of stage ⅣA and ⅣB patients were 71.8% and 46.2%,respectively (P=0.171),and that of stage ⅠVC patients was only 24.0%.In stage Ⅲ,the 5-year DSS rate of non-T3N2M0 patients (91.5%) was significantly higher than that of T3N2M0 patients (78.6%)(P=0.042),but there was no significant difference in DSS between T3N2M0 patients and stage ⅣA and ⅣB patients.Based on the above results,new stage Ⅰ included T1-3N0-1M0 and T1-2N2M0,new stage Ⅱ included T3N2M0,T4N0-2M0,and TxN3M0,and new stage Ⅲ included TxNxM1.The 5-year DSS rates of new stage Ⅰ,Ⅱ,and Ⅲ patients were 93.3%,72.7%,and 24.0%,respectively (P=0.000).Compared with new stage Ⅰ patients,new stage Ⅱ and Ⅲ patients had HRs of 4.01 and 16.76,respectively,for 5-year DSS.Conclusions In the era of IMRT,the new clinical staging system (stages Ⅰ,Ⅱ,and Ⅲ) helps with prognostic evaluation and clinical treatment.