Analysis Of Responses And Prognostic Factors In Radical Radiotherapy For 135 Patients With Nasopharyngeal Carcinoma

Objective:To analyze and compare the responses of radiotherapy alone group with radiochemotherapy group,and evaluate the responses of different radiotherapy techniques for patients with nasopharyngeal carcinoma?NPC?,and explore the prognostic factors and the late adverse reactions for NPC.Methods:We retrospectively analyzed the clinical data of 135 patients,who were initial diagnosed with NPC by pathology at the department of radiation oncology,China-Japan Union Hospital of Jilin University between January 2010 to December 2016,and the last follow-up deadline by December 2017.Radiotherapy techniques included three dimensional conformal radiotherapy?3D-CRT?and intensity modulated radiotherapy?IMRT?.Chemotherapy modality was composed of neoadjuvant chemotherapy,concurrent chemotherapy and adjuvant chemotherapy,of which regimens was made up of platinum alone or platinum-containing combination regimens.The RECIST evaluation criteria were used to analyze the short-term clinical response,and RTOG radiation injury grading criteria were used to evaluate late adverse reactions.The Log-rank univariate analysis was used for comparing with overall survival?OS?,progression-free survival?PFS?,loco-recurrence-free survival?LRFS?,and distant metastasis-free survival?DMFS?.The Cox regression model was used to conduct the multivariate analysis.The rank sum test was applied to compare the short-term response between radiotherapy alone and radiochemotherapy group,3D-CRT group and IMRT group as well.Kaplan-Meier was devoted to compare with OS,PFS,LRFS and DMFS after 1,2,3,4 and 5 years later for NPC.The chi-square test was applied to compare the differences with late adverse reactions in different groups.P value<0.05 was considered statistically significant.Results:1.Prognostic factors for NPCThe Log-rank univariate analysis showed that the short-term response?complete remission?CR?or not?for OS,PFS,and LRFS was statistically different?P<0.05?.The different techniques of radiotherapy?3D-CRT and IMRT?for PFS was significant?P<0.05?.Gender was significant for DMFS?P<0.05?.T-stage(T_1-2-2 and T_3-4)was statistically different for PFS,LRFS,and DMFS?P<0.05?.N-stage(N_0-1-1 and N_2-3)was significant for DMFS?P<0.05?,and clinical stage?I-II and III-IV?for OS,PFS and DMFS were statistically different?P<0.05?.The Cox multivariate analysis showed that the short-term response?CR or not?was an independent prognostic factor for OS,PFS,and LRFS.Radiotherapy technique?3D-CRT and IMRT?was an independent prognostic factor for PFS and DMFS.2.The short-term responseAmong 135 patients with NPC after treatment,69 patients achieved CR,65patients were partial remission?PR?,1 patient was stable disease?SD?,and no patient with disease progression?PD?.The overall response rate?ORR?was 99.3%.There were non-significant differences between the radiotherapy alone group and the radiochemotherapy group,and also between the 3D-CRT group and the IMRT group?P>0.05?.3.The long-term responseThe OS rate after 1,2,3,4,and 5 years for 135 patients with NPC was 90.4%,87.4%,85.2%,83.0%and 82.2%,respectively;the PFS rate was 88.1%,83.7%,79.3%,77.0%and 74.8%;the LRFS rate was 96.3%,95.6%,94.1%,93.3%and91.9%;the DMFS rate was 92.6%,89.6%,87.4%,85.2%and 84.4%.There existed statistically different between the radiotherapy group and the radiochemotherapy group for 2-year and 3-year OS?P<0.05?.The 1-year DMFS between 3D-CRT group and IMRT group was significant?P<0.05?.4.The late adverse reactionsOnly 86 patient?67.7%?of late adverse reactions were recorded through follow-up.Adverse reactions such as mild impairment with salivary glands,mucous membranes,and esophageal were the mainly side reaction and no more serious adverse reactions.There were no significant differences between the radiotherapy alone group and the radiochemotherapy group,and also between the 3D-CRT group and the IMRT group?P>0.05?.Conclusion:1.Radiotherapy is the preferred treatment method for NPC.The short-term response is an independent prognostic factor for OS,PFS,and LRFS.Radiotherapy technique is an independent prognostic factor affecting the PFS and DMFS.2.Radiochemotherapy can improve the 2-year and 3-year OS.IMRT technology can improve the 1-year DMFS.3.After radical radiotherapy for nasopharyngeal carcinoma,late-stage adverse reactions are mainly grade 1 and grade 2.Only a few patients occurred grade 3 or more serious adverse reactions.