Comparative Study Of The Simultaneous Integrated Boost-IMRT And Sequential Boost Of Esophageal Squamous Cell Carcinoma

Objective:The aim of this study was to compare and analyze the prognosis survival and side effects of esophageal cancer treated by simultaneous integrated boost-IMRT（SIB-IMRT）and sequential boost-IMRT using radiotherapy alone.In order to provide the individualized treatment plan for patients with esophageal carcinoma of unable receiving concurrent chemotherapy.Methods:This retrospectively analysis was of 152 patients with esophageal squamous cell carcinoma who underwent radiotherapy alone in our hospital from January 2006 to December 2015,the whole group of patients only received radical radiotherapy because of physical conditions or medical disease carrying that could not tolerate chemotherapy or refuse chemotherapy.All the 152 patients have received elective nodal irradiation,including 51patients were treated by simultaneous integrated boost（SIB-IMRT）.All the clinical characteristics for example,gender,age,tumor location,tumor length,T stage,N stage,TNM stage,tumor volume of GTV,invasion of esophageal lesion,irradiated mode and prescription dose were compared and analysed in SIB-IMRT group and sequential boost group,and explored the differences of survival rate and local control rate between the two groups.Univariate and multivariate statistical analysis were carried out wuth all relevant prognosis factors in the whole group,SPSS21.0 statistical software was used to analyze,and Kaplan-Meier method for the local control and survival,and Log-rank test was used.Results:The follow-up time was cut off at the end of 2018 with 3 patients lost and the follow-up rate was 98.0%.The 1-year,3-year,5-year overall survival rates of all patients were 78.9%39.5%,26.5%,and local control rates were75.6%,49.4%,43.6%,respectively.The univariate analysis showed that the hoarse,organs invaded by tumor,tumor volume of GTV,the length of tumor,T stage,TNM stage and the occurrence of radioactive esophagitis were the significant influence factors to overall survival.Organs invaded by tumor was the in-dependent influence factors of local control.The Cox multivariate analysis revealed that TNM stage and organs invaded by tumor were independent prognostic factors of overall survival and local control.When GTV volume>35cm³,tumor length>5cm,T₃+T₄ phase,III+IV phase,the survival rate of SIB-IMRT group was significantly higher than that of sequential boost group（31.9%vs 7.1%P=0.033;39.7%vs 11.4%P=0.042;34.3%vs 8.8%P=0.045;29.6%vs 14.9%P=0.034）.There was no significant difference in the incidence of≥2 grade acute radiation esophagitis between the two groups.but had a statistically significant difference in the incidence of≥2grade acute radiation pneumonitis between the two groups,（16.8%vs 5.9%,P=0.039）.The V5,V10,V20 and MLD of lungs in the SIB-IMRT group were significantly lower than those in the sequential boost group when the volume of GTV was>35cm³,the length of tumor was>5cm,and the stage of T₃+T₄（P<0.05）.Similarly,the V30,V40,V45,V50,MHD values of heart in the SIB-IMRT group can be clearly reduced in SIB-IMRT group（P<0.05）.Conclusions:1 In patients with advanced esophageal cancer treated with the radical radiotherapy with ENI,there were no significantly differences in local control and the overall survival rates.however,SIB-IMRT group had better trend than sequential boost group.2 The overall survival rate had a statistically higher in the SIB-IMRT group than sequential boost group when the larger tumor volume,longer tumor length and advanced TNM stage,the normal tissue in SIB-IMRT group was significantly lower than the sequential boost group,reducing the incidence of adverse reactions and provide a reference of individualized treatment options.