Clinical Outcomes And Prognostic Analysis On N3 Nasopharyngeal Carcinoma With Intensity-modulated Radiotherapy

Purpose: To investigate optimal treatment scheme for N3 nasopharyngeal carcinoma through observing the clinical outcomes of IMRT(intensity-modulated radiotherapy)and analyzing prognostic factors,which provides reference for the research and clinical treatment.Methods: 125 nasopharyngeal carcinoma patients who had been confirmed by pathological examination without distant metastasis in the First Affiliated Hospital of Guangxi Medical University from Jan.2009 to Dec.2013 were selected as research objects.On the basis of their preliminary clinical data as well as imaging data(CT and MRI),they were categorized into T1-4N3M0 phase according to 2017 UICC/AJCC clinical staging standard(the 8-th Edition),all receiving IMRT.Their various types of survival rates(OS,PFS,RFS and DMFS)were calculated by Kaplan-Meier method.The intergroup difference was compared by single factor analysis and tested by Log-rank method.Cox regression model was applied in multivariate prognostic analysis.Results: Follow-up examination varied from 3 to 93 months in time length,with median follow-up time of 50 months.Of all 125 patients with N3 nasopharyngeal carcinoma,there were 50 deaths(50/125,40%),including 44 treatment failure-caused deaths(44/125,35.2%),2internal medicine disease-caused death(2/125,1.6%),and 4 deathscaused by unknown reason(4/125,3.2%).Of 44 cases of treatment failure,there were 34 cases of distant metastasis(34/44,77.2%),12 cases of relapse(12/44,27.2%),4 cases of replase combined with distant metastasis(4/44,9.1%),and 2 cases of uncontrolled tumor(2/44,4.5%).1,3,4-year OS was 92.8%,70.4%,63.2%,,respectively;1,3,4-year PFS was 87.1%,64.5%,59.7%,respectively;the 1,3,4-year RFS was 98.4%,91.9%,90.3%,respectively;the 1,3,4-year DMFS was88.6%,74.8%,73.2%,respectively.The single factor and multifactor analyses showed that anemia,the number of chemotherapy cycle,chemotherapy method,T staging were independent prognostic factors for OS;anemia,the number of chemotherapy cycle,T stage were independent prognostic factors for PFS;anemia,the number of chemotherapy cycle were independent prognostic factors for DMFS;T staging was the only independent prognostic factors for RFS.Conclusion: The combined application of radiotherapy with at-least4 cycles of platinum-based chemotherapy can significantly improve the prognosis of patients with N3 nasopharyngeal carcinoma.The selection of optimal chemotherapy combination and chemotherapy drug needs to be further studied.Correction of anemia may become an effective intervention means to improve survival and rate of no distant metastasis.