A Case-control Study On The Relationship Between Smoking And Lung Metastasis In Patients With Nasopharyngeal Carcinoma

Background and Purpose：Nasopharyngeal carcinoma is a malignant epithelialoriginal tumor,with the high incidence in the south of China.When diagnosed withnon-metastatic patients after radical radiotherapy are still about20%to30%haddistant metastases,and a lot of scholars point that distant metastasis is one of the mainreasons for failure in nasopharyngeal carcinoma.Our country is a big country ofsmoking,espically,male smoking rate is highest in the world. Existing documentsindicated that smoking can change lung’s microenvironment,and there are a lot ofspecialists consider that this change can affect the tumor cell,s grow, invasion,survivaland growth.Therefore,our study aim to observe the effects of smoking on lungmetastasis of nasopharyngeal carcinoma.Material and method:This is a matched case-control study.All male NPCpatients initially presenting with no distant metastasis were treated with radicalradiotherapy in Jiangxi Provincial Tumor Hospital Department of RadiationOncology from June2008to June2011.We select46clearly diagnosised ofpulmonary metastasis patients as case group;the control group are divided into twogroups: the extra-pulmonary metastasis group; no distant metastasis.All groups pairwith1:1:2byT、N、08stage,and were46case、46case、92case. Reviewing of allpatients’s clinical data and,record relativied message:the first admissionage,height,weight, KPS score and other general.then calculate body mass index(BMI),Recording first admission lactate dehydrogenase(LDH) and hemoglobin(HBG)by collecting fasting blood and testing.Calendaring smoking status (smoking=activesmoking&quit smoking less than five years;no smoking=never smoking&Quitsmoking more than five years).Cassetting patient treatment (chemotherapy,radiotherapy).Using Excel2003establish a database table with obtained data,andusing SPSS version18.0for data processing:Rank test to compare the three groupsT,N,08stage;Chi-square test to compare the four groups age,KPS score,smokingstatus,whether chemotherapy, radiotherapy methods and metastasis;t test to compareBMI index, LDH, HGB； Logistic regression analysis used for univariate and multivariate analysis.Results:(1) General:three groups of patients in the T,N,08stage,age,KPS score,wheather chemotherapy and radiotherapy methods were not statistically different (p>0.05).(2)Stages:Three groups of patients have no significant statistically difference inthe T, N,08stage(p>0.05).(3)Treatment:whether chemotherapy or not,taking IMRTtreatment or Ordinary radiotherapy had no effect for the transfer (p>0.05).(4)Smoking、anemia、lower BMI index、higher LDH were not statistical link (p>0.05) of pulmonary metastasis group and no distant metastasis group、extra-pulmonary metastasis and no distant metastasis group、pulmonary metastasisgroup and extra-pulmonary metastasis.(5)Univariate analysis and Multivariateanalysis showed that Smoking（p=0.028，Exp(B)=2.694，95%CI=1.366-5.315）、anemia（p=0.037，Exp(B)=2.606，95%CI=1.058-6.420）、lower BMI index（p=0.019，Exp(B)=3.046，95%CI=1.199-7.733）、higher LDH（p=0.044，Exp(B)=2.909，95%CI=1.030-8.215）were independent prognostic factors.Conclusion: Smoking can lead to a higher rate of distant metastasis fornasopharyngeal carcinoma, but it seems not to be much relationship with metastaticsites.In addition,NPC patients with anemia, low BMI, elevated LDH are more likelyto distant metastases.