Risk Factors For Distant Metastasis Of Nasopharyngealcarcinoma Patients Treated With Intensity-Modulated Radiotherapy

Objective:The objective of this study is to identify the risk factors for distant metastasis(DM)of nasopharyngeal carcinoma(NPC)patients treated with intensity-modulated radiotherapy(IMRT).Methods:We analysed retrospectively 155 non-metastasis NPC patients in First Affiliated Hospital of Guangxi Medical University between January 2011 and December 2011.All of patients were treated with IMRT.The median follow-up time was 52 months(3-72 months).The independent risk factors for DM were tested by Kaplan-Meier and the multivariate Logistic regression analysis.Results: 1.Among the patients we followed up,DM occurred in 24 patients.The5-year DM rate was 16.2 %.DM occurred in bones to 16 patients with 13 patients in lungs and 7 patients in patients.The 1,2,3,4,5-year DM rate were41.7%,62.5%,79.2%,83.3%,95.8%respectively.The median time of DM was 11 months(4-53months).2.N2–3,haemoglobin change after treatment(? HGB)? 28g/L,pretreatment platelet PLT ? 300*10^9/L,albumin-globulin ratio(AGR)<1.32 were adverse independent predictive factors for DM of NPC patients treated with IMRT.3.There was no significant difference between the neoadjuvant chemotherapy(NACT)+concurrent radiochemotherapy(CCRT) group in DM rate(X 2 =0.008,P=0.928).There was also no significant difference between the NACT+CCRT group and CCRT group +adjuvant chemotherapy(ACT)group in DM rate(X2=0.422,P=0.516).Conclusion:1.Distant metastasis occursmost in 1 year.The number become stable after 3 years.The most common metastasis site is bone,followwed by lungs and livers.2.N2-3,?HGB?28 g/L,pretreatment PLT?300*10^9/L,AGR<1.32 are adverse independent predictive factors for DM.Monitoring these indicators can help us evaluate the risk of DM in IMRT-treated NPC patients and guide future individualized treatment.3.Compared with CCRT±ACT,it needs further study if NACT+CCRT can reduce DM rate.It also needs further study about the effect of NACT+CCRT on DM rate in NPC pantients.