A Study On Radiation Pneumonitis Following Hypo-Fractionated Radiation Therapy In Non-Small-Cell Lung Cancer

Objective:This study was undertaken to retrospectively evaluate the clinical and dosimetric prognostic factors for radiation pneumonitis (RP) after hypo-fractionated radiotherapy (RT) in patients with non-small cell lung cancer (NSCLC).Methods:We retrospectively analyzed the clinical and DVH data from32non-small celllung cancer patients treated with3-dimensional conformal radiation therapy(3DCRT) between January2009and August2012. Among them,18cases are male and14cases are female;20patients under60years of age,12cases of patients aged60and over;12cases of squamous cell carcinoma and20cases of adenocarcinoma. There were8cases treated with radiotherapy alone, and24cases combined chemotherapy. ALL of them have complete radiotherapy plans. All patients were diagnosed pathologically as non-small cell lung cancer for stage I toIV and received a three-dimensional conformal radiotherapy. Radiation pneumonitis was scored by using Radiation Therapy Oncology Group criteria. To evaluate the radiation pneumonitis occurred within3months after radiotherapy. Grade3RP was defined as an RP event. Using SPSS17.0software analysis the relationship of patients’gender, age, clinical stage, histological type, lesion, specific leaf chemotherapy history, smoking history, history of previous lung disease, tumor volume and dose parameters V10, V20and radiation pneumonitis (RP). X2exact test was performed to compare clinical parameters between patients who developed severe RP and those who did not. logistic logistic regression analyses were performed to evaluate data for association between dose-volumetric parameters and severe RP. P<0.05is considered statistically significant difference. Result:All patients completed the entire radiation therapy plan. Evaluate the radiation pneumonitis in3months after radiotherapy.10patients suffered the-S3acute radiation pneumonitis.The overall incidence rate was31.3%(10/32). Univariate analysis showed that the clinical factors (patient gender, age, clinical stage, histological type, lesion, chemotherapy history, smoking history, history of previous lung disease, tumor volume) had no significant effect on the occurrence of radiation pneumonitis, and the tumor leaf, maximum dose and mean dose of ipsilaterallung, V10, V20significantly affect the incidence of radiation pneumonitis in patients. Multivariate Logistic regression analysis showed a significant correlation in the V20and radiation pneumonitis occurred.Conclusion:The radiation pneumonitis occurrence is the result of the interaction of the various clinical and dose factors. The tumor leaf, maximum dose and mean dose of ipsilateral lung, V10, V20affect the incidence of radiation pneumonitis in patients, and V20most significant impact. When making radiotherapy plan, you can predict the degree of the radiation pneumonitis risk through V20factors,and then adjust the radiotherapy plan in time, in order to effectively reduce the risk of r radiation pneumonitis...