Predicting the Risk of Radiation Pneumonitis and Pulmonary Function Changes after Breast Cancer Radiotherapy

Background: Radiotherapy plays an important role in the treatment of breast cancer. In the process of radiotherapy, the underling lung tissue receives higher doses from treatment field, which led to incidence of radiation pneumonitis. Objective: The present study aims to evaluate the predictive factors of radiation pneumonitis and related changes in pulmonary function after 3D-conformal radiotherapy of breast cancer. Material and Methods: In prospective basis study, thirty-two patients with breast cancer who received radiotherapy after surgery, were followed up to 6 months. Respiratory symptoms, lung radiologic changes and pulmonary function were evaluated. Radiation pneumonitis (RP) was graded according to common terminology criteria for adverse events (CTCAE) version 3.0. Dose-volume parameters, which included percentage of lung volume receiving dose of d Gy (V5-V50) and mean lung dose (MLD), were evaluated for RP prediction. Pulmonary function evaluated by spirometry test and changes of FEV1 and FVC parameters. Results: Eight patients developed RP. Among the dose-volume parameters, V10 was associated to RP incidence. When V10