Analysis Of Factors Related To Distant Metastasis After Treatment In Patients With Nasopharyngeal Carcinoma

Objective1.To explore the clinically influential factors of distant metastasis(DM) after treatment in patients with nasopharyngeal carcinoma(NPC),and to analyze synthetically the rule and influential factors of DM by the index equation(IE) that was built using Cox regression model;2.To study the expression of vascular endothelial growth factor(VEGF) and matrix metalloproteinase-9(MMP-9) and its correlation with DM.Materials and methodsFrom May 2001 to February 2007,there were 158 patients with NPC admitted to Department of Oncology,Xinqiao Hospitaland,and they had distant metastasis discovered above half a year after final diagnosis.Clinically influential factors were analyzed retrospectively and IE for distant metastasis was built using Cox regression model and calculated on basis of multivariable analysis.According to IE values,patients were categorized into 4 different risk groups and inter-group comparison was made with Log-rank methods.To evaluate the relationship between the expression levels of VEGF and MMP-9, between the expression levels of either VEGF or MMP-9 and clinical factors,including gender,age,family medical history,T stage,N stage,clinical stage,metastasis of cervical lymph node and post-treatment distant metastasis,immunohistochemical streptavidin peroxidase(SP) were utilized to detect the expression of VEGF and MMP-9 in nasopharyngeal tissue sample of 51 cases collected from Department of Pathology, Xinqiao Hospital on the basis of clinical data of 158 with nasopharyngeal carcinoma.Results1.Organs in which the distant metastasis easily occurred for the 158 patients were bone in 75 cases(47.5%),lung in 58 cases(36.7%),liver in 54 cases(34.2%),.In 38(24.1%) patients multi-organ metastasis was discovered at the same time. 2.The distant metastasis occurred in 107 cases(67.7%) between half a year and two years after final diagnosis,in 56 cases between half a year and one year,in 51 cases between a year and two years,in 30 cases between two years and three years,and in 21 cases above three years.The longest time from final diagnosis to DM is 9.2 years.3.Single factor analysis showed that T stage,N stage,clinical stage,cervical lymph nodes metastasis,and cervical radiation dose were influential factors of distant metastasis after treatment(P＜0.05).Layering analysis for clinical stage revealed that survival rate of two years without DM for patients of chemotherapy ofⅢ,Ⅳstage with NPS was respectively 28.3%,4.2%,higher than that for patients of non-chemotherapy (P＜0.05).4.Multivariable factors analysis for 158 cases with NPC revealed that N stage, clinical stage,chemotherapy were main influential factors of distant metastasis with patients of NPC after treatment.Difference of survival rate without DM in different risk groups was very significant(P＜0.01).5.VEGF was expressed in 37 of 51(72.5%) cases of NPC,MMP-9 in 39 of 51(76.5%) cases.No statistical significant difference was observed between expression of either VEGF or MMP-9 and gender,age,family medical history,and T stage(P＞0.05).Their expression was statistical significant difference with cervical lymph nodes metastasis,N stage,clinical stage.This study showed positive correlation between the expression of VEGF and MMP-9.6.The expression of either VEGF or MMP-9 was negative correlation with distant metastasis after treatment in NPC.The more stronger their expression is,the more earlier distant metastasis of patients with NPC will occur.Multivariable factors analysis revealed that VEGF and MMP-9 also were independently influential factors of distant metastasis after treatment with patients of NPC.Conclusions1.The distant metastasis of most NPC occurred within two years after final diagnosis.Predominant organs for metastasis were bone,lung,liver.2.N stage,clinical stage and chemotherapy were mainly and clinically influential factors of distant metastasis with patients of NPC after treatment.IE value will objectively predict risk of distant metastasis in these patients,and revealed evidence for clinicians to formulate individualized treatment regimen.3.VEGF and MMP-9 might play a important role in process of invasion and metastasis,will be biological parameter predicting distant metastasis,and will show evidence to anti-angiogenesis regimen in patients with NPC.