Study The Relationship Among Endothelin-1 (ET-1),Lung Dose-Volume Histogram Parameters V20 And Radiation-induced Lung Injury

Objectives: To investigate pretreatment,duringtreatment(40Gy),posttreatment plasma ET-1 levels and Dose-Volume Histogram Parameters V20 associated with radiation-induced lung injury.Methods : Forty-eight lung cancer patients who received 3DCRT,the tumor doses ranged from 54 to 66Gy, delivered in 2Gy per fraction, 5 times per week. Make V20≤30% and the dose of spinal cord≤45Gy. Use the method of ELISA to quantitate the concentration of pretreatment,duringtreatment(40Gy) and posttreatment plasma ET-1.Make clinical examination and CT every one or two week.Apply RTOG radiation scoring criteria to assess radiation-induced lung injury.Results: The totle incidence of radiation-induced injury was 27.1%(13/48), 12.5%(6/48) of patients were≥GradeⅡradiation-induced lung injury . When received 40Gy, the incidence of lung injury whose ET-1 levels elevated was 41.7 % markedly higher than those who have normal ET-1 levels(12.5%)(P=0.023).After the therpy, the incidence of lung injury whose ET-1 levels elevated was 44% significantly higher than those who have normal ET-1 levels 8.7%(P=0.006). The radiation-induced lung injury incidence of whose V20≥25% and plasm ET-1 levels elevated posttherapy was 69.2%,especially higher than other groups , The results have significant difference(P<0.05). The radiation-induced lung injury incidence of patients whose V20<25% and with normal ET-1 levels after therpy was 5.9%,significant lower than other groups. The incidence of radiation-induced lung injury of those patients who combined chemistry therpy was 37.9%,markedly higher than those who received radiation only10.5%(P=0.037).Conclusion: The radiation-induced lung injury was significantly related to the concentration of plasma ET-1 during and after radiation therpy. The patients whose V20≥25% and ET-1 levels elevated during or after radiation therpy have markedly higher incidence of radiation-induced lung injury than other groups. Patients who combined chemistry therpy have their incidence of radiation-induced lung injury increased markedly.