A Study Of Three Dimensional Conformal Radiotherapy For Stageâ…¢ Non-small Cell Lung Cancer

PartⅠDosimetric Comparison between Conventional and Three Dimensional Conformal Radiotherapy for StageⅢCentral Non-small Cell Lung CancerObjective:To compare the dose distribution by three dimensional conformal treatment planning system(TPS) for the primary lesion and normal tissues between conventional and three dimensional conformal radiotherapy for stageⅢcentral non-small cell lung cancer.Methods:Thirty-two patients were allotted to receive both conventional simulation and CT simulation in the same treatment position.Three kinds of treatment plans were designed for each patient:1.Three dimensional conformal radiotherapy plan(3DCRT),2.Virtual comprehensive treatment plan(VCTP),i.e. it consisted of conventional radiotherapy first , followed by conformal plan , 3 . Conventional treatment plan(CTP) .All plans were received conventional fraction,the total radiation dose was 60Gy.Dose volume histogram(DVH) was applied to evaluate the different of dose distribution for tumors and normal tissues among the three plans. Results:In three kinds of plan,the maximum dose at GTV were 64.3Gy,67.1Gy,60.9Gy, the mean dose were 60.0Gy,62.6Gy,57.6Gy, and the minimum dose 55.9Gy,57.1Gy,52.2Gy,respectively. the maximum dose at CTV were 67.0Gy,66.1Gy,63.1Gy, the mean dose were 60.8Gy,60.8Gy,58.0Gy, and the minimum dose were 55.3Gy,56.4Gy和50.8Gy,respectively. The target dose of 3DCRT was higher than that of CTP, but lower than that of VCTP, parts of the data have statistical significance. 3DCRT and VCTP could meet the demands of dosimetric requirements for radiation treatment. At the radiation dose to the normal tissue, the whole lung volumes which received radiation dose of≥20Gy(V20) at the three designs were 22.2%,32.4% and 26.4%,≥30Gy(V30) were 12.1%,21.0% and 20.3%, the mean dose were 16.5Gy,27.2Gy and 22.5Gy, respectively. The maximum dose at the heart were 50.3Gy,56.2Gy and 57.5Gy, V35 were 27.1%,29.5% and 29.6%, respectively. The maximum dose at the spinal cord were 30.0 Gy,40.0Gy and 38.8Gy, the mean dose were 10.3Gy,24.6Gy and 21.9Gy, and the spinal cord volume which received radiation of≥40Gy (V40) were 3.3%,10.6% and 11.4%,respectively. The maximum dose at the esophageal were 47.6Gy,55.9Gy and 49.8Gy, the length of esophagus(total circumference) treated with≥45Gy(LETT45) were 5.6cm,7.2cm and 6.5cm, and the volume which received radiation of≥45Gy(V45) were 30.7%,47.6% and 38.5%, respectively. 3DCRT were superior to VCTP and CTP in the volume and dose of lung and spinal cord and esophageal.Conclusions:3DCRT could achieve more irradiation dose to the target volumes and reduce irradiation dose to normal tissue at the same time compared with the VCTP and CTP, which contributes to raise the local control rate. PartⅡStudy on Vinorelbine plus Cisplatin Chemotherapy with Concurrent Three-Dimensional Conformal Hypofractionated Radiotherapy (3DCRT) for StageⅢNon-Small Cell Lung CancerObjective:To evaluate the clinical toxicity and effect of three-dimensional conformal hypofractionated radiotherapy with concurrent vinorelbine plus cisplatin chemotherapy for StageⅢNon-Small Cell Lung CancerMethods: 42 patients were randomly divided into two groups:20 patients were received conventional fraction 3DCRT(control group),The fraction was 2 Gy, 5 times every week,the total dose was 60-70Gy.22 patients were given three dimensional conformal hypofractionated radiotherapy (experimental group),these patients were received 4Gy per fraction,3 times every week,to a total dose of 48-56Gy.42 cases were also given concurrent NP chemotherapy.The chemotherapy regimen consisted of 3-4 cycles of vinorelbine 20mg/m2 for weekly administration in Saturday,cisplatin 20mg/m2 in Saturday and Sunday.Toxicities and effects were evaluated according to the criteria of WHO.The survival rate was calculated and survival curve was plotted by Kaplan-Meier.Results:All the patients have finished the trial.The complete response(CR) rate was10%(2/20) and partial response(PR) rate was 65%(13/20) in control group.No change and progress disease (NC+PD) was 25% (5/20).The overall response rate (CR+PR) was 75% (15/20),and 1-year survival rate was 75% (15/20).While the CR rate was 18% (4/22) and PR 68% (15/22) in experimental group,NC and PD was 14% (3/22).Total CR and PR was 86.4%(19/22) in experimental group,and 1-year survival rate was 86.4%(19/22).2-3 grade of esophagitis and pneumonia and leukocytopenia in control group and experimental group were 60.0%(12/20) and 72.7%(16/22) ,20.0%(4/20) and 22.7%(5/22),25.0%(5/20) and 31.8%(7/22).Conclusions : Three-dimensional conformal hypofractionated radiotherapy with concurrent low dose NP chemotherapy for StageⅢNon-Small Cell Lung Cancer is tolerable and improved response rate,long survival time is still farther observed.