Analysis Of The Prognosis And The Influence Factors Of Image Residue At The End Of Intensity Modulated Radiotherapy For Nasopharyngeal Carcinoma

ObjectiveIn the current study,we retrospectively analyzed the prognostic influencing factors of nasopharyngeal carcinoma(NPC)patients treated with intensity-mod ulated radiotherapy(IMRT),including imaging residual after IMRT,times of im aging residual disappearing,and several survival rates.The results of this study could bring deeper insights into the treatment and prognosis conditions of NPC cases.MethodsFrom June 2008 to June 2016,691 NPC patients that treated by IMRT in the affiliated tumor hospital of Guangxi medical university were followed-up.The correlated factors including imaging T residual,time of survival,recurrence,metastasis and related influencing factors.Chi-square test was used to compare the differences of residual rates among groups and the risk factors of imaging T residual were screened utilizing logistic regression model.Meanwhile,NPC patients' overall survival(OS),local recurrence-free survival(LRFS)and distant metastasis-free survival(DMFS)in 5-year were calculated based on the lifetime table.The prognosis-related factors were analyzed by Kaplan-Meier(KM)plots and the Log-rank model statistically tested differences of survival rates among groups.Furthermore,Cox Proportional Hazard Regression Model was employed for extracting risk factors.Results1.32.9% and 31.0% NPC patients were found to be existed imaging T and N residual after IMRT curing.2.Results of multivariate analysis revealed that the male sex,aged patients,invasive sites(including Pars oralis pharynges,basis cranii,cavernous sinus,cranial nerve)were the risk factors of imaging T residual(P<0.05).3.NPC patients at following N stages(IIa stage,III stage,VIIa stage)with tumor invasion were considered as the strong risk factors of imaging N residual(P<0.05).4.Residual lymph nodes,T residual and T+N residual were identified as the risk factors for the time of imaging residual disappearing over 3 months.5.Several survival rates were analyzed(OS=81.8%,LRFS=93.3%,DMFS=82.1%).Meanwhile,via multivariate analysis of OS,aged patients at advanced N stage and with imaging residual were the risk factors of death(P<0.05).Similarly,advanced N stage and imaging residual could induce relapse of NPC,but simple induction chemotherapy and PF-chemotherapy + adjuvant chemotherapy were taken as the protective factors of recurrence of NPC(P<0.05).For metastasis of NPC,imaging residual and advanced N stage were considered as the risk factors,and simple induction chemotherapy,simple PF-chemotherapy and PF-chemotherapy + adjuvant chemotherapy were the protective factors(P<0.05).Conclusions1.Imaging T or N residual would be significantly affected by the sex and age issues,as well as whether tumor cells invaded the parts of pars oralis pharynges,basis cranii,cavernous sinus or cranial nerve.Furthermore,invasion progress of NPC cells in lymphoma nodes at IIa,III and VIIa of N stages can also indicate crucial evidence of imaging T or N residual conditions after IMRT treatment.2.We found the risk factors of NPC patients,such as residuals of NPC cells in lymphoma nodes,imaging T residual,imaging T+N residual and residual disappearing time over 3 months.3.Meanwhile,we should focus on the patients who are probably in a poorer prognosis due to the prognostic risk factors,including the aged,patients with imaging residual,advanced N stages and so on.Therefore,as the protective factors of NPC prognosis,simple induction chemotherapy,simple PF-chemotherapy and PF-chemotherapy + adjuvant chemotherapy should be actively promoted to reduce the relapse and improve the survival rates of NPC patients.