Prediction of Radiation-induced Pulmonary Function Loss in Post-operative Radiotherapy for Non-small Cell Lung Cancer Using a Fibrosis Volume Model

Abstract

Purpose/Objective(s)To evaluate radiation-induced pulmonary function loss in post-operative radiotherapy (PORT) for non-small cell lung cancer (NSCLC) using the volume of radiation-induced pulmonary fibrosis.Materials/MethodsPatients with NSCLC who were treated with PORT were enrolled in this investigation. Pulmonary function tests (PFTs) were determined pre-operatively, pre-PORT, and > 6 months after PORT. Pre-PORT PFTs were also estimated from preoperative PFTs using a quantitative CT method. The volume of radiation-induced pulmonary fibrosis (Vf) was evaluated on chest CT scan > 6 months after the completion of PORT. The correlations among the dosimetric parameters of the lung, Vf, and radiation-induced pulmonary function loss were analyzed.ResultsBetween January 2003 and January 2007, 48 patients were treated with conformal radiotherapy. The mean values of FEV1 were 2.16 L pre-operatively, 1.65 L pre-PORT; 1.61 L estimated pre-operatively, and 1.59 L during follow-up PFTs. PORT showed no additional decline in FEV1 (estimated pre-PORT FEV1 vs. follow-up FEV1 [1.63 L vs. 1.59 L]; p = 0.48). The radiation-induced pulmonary function loss was well-correlated with the dosimetric parameters (V25; r = -0.734; p < .01), as well as the Vf (r = -0.695; p < .01).ConclusionsThe degree of radiation-induced pulmonary function loss can be predicted by the dosimetric parameters of the lung in patients with NSCLC who underwent surgical resection followed by PORT. Radiation-induced fibrosis volume can be used as a quantitative imaging marker in assessment of radiation-induced pulmonary injury. Purpose/Objective(s)To evaluate radiation-induced pulmonary function loss in post-operative radiotherapy (PORT) for non-small cell lung cancer (NSCLC) using the volume of radiation-induced pulmonary fibrosis. To evaluate radiation-induced pulmonary function loss in post-operative radiotherapy (PORT) for non-small cell lung cancer (NSCLC) using the volume of radiation-induced pulmonary fibrosis. Materials/MethodsPatients with NSCLC who were treated with PORT were enrolled in this investigation. Pulmonary function tests (PFTs) were determined pre-operatively, pre-PORT, and > 6 months after PORT. Pre-PORT PFTs were also estimated from preoperative PFTs using a quantitative CT method. The volume of radiation-induced pulmonary fibrosis (Vf) was evaluated on chest CT scan > 6 months after the completion of PORT. The correlations among the dosimetric parameters of the lung, Vf, and radiation-induced pulmonary function loss were analyzed. Patients with NSCLC who were treated with PORT were enrolled in this investigation. Pulmonary function tests (PFTs) were determined pre-operatively, pre-PORT, and > 6 months after PORT. Pre-PORT PFTs were also estimated from preoperative PFTs using a quantitative CT method. The volume of radiation-induced pulmonary fibrosis (Vf) was evaluated on chest CT scan > 6 months after the completion of PORT. The correlations among the dosimetric parameters of the lung, Vf, and radiation-induced pulmonary function loss were analyzed. ResultsBetween January 2003 and January 2007, 48 patients were treated with conformal radiotherapy. The mean values of FEV1 were 2.16 L pre-operatively, 1.65 L pre-PORT; 1.61 L estimated pre-operatively, and 1.59 L during follow-up PFTs. PORT showed no additional decline in FEV1 (estimated pre-PORT FEV1 vs. follow-up FEV1 [1.63 L vs. 1.59 L]; p = 0.48). The radiation-induced pulmonary function loss was well-correlated with the dosimetric parameters (V25; r = -0.734; p < .01), as well as the Vf (r = -0.695; p < .01). Between January 2003 and January 2007, 48 patients were treated with conformal radiotherapy. The mean values of FEV1 were 2.16 L pre-operatively, 1.65 L pre-PORT; 1.61 L estimated pre-operatively, and 1.59 L during follow-up PFTs. PORT showed no additional decline in FEV1 (estimated pre-PORT FEV1 vs. follow-up FEV1 [1.63 L vs. 1.59 L]; p = 0.48). The radiation-induced pulmonary function loss was well-correlated with the dosimetric parameters (V25; r = -0.734; p < .01), as well as the Vf (r = -0.695; p < .01). ConclusionsThe degree of radiation-induced pulmonary function loss can be predicted by the dosimetric parameters of the lung in patients with NSCLC who underwent surgical resection followed by PORT. Radiation-induced fibrosis volume can be used as a quantitative imaging marker in assessment of radiation-induced pulmonary injury. The degree of radiation-induced pulmonary function loss can be predicted by the dosimetric parameters of the lung in patients with NSCLC who underwent surgical resection followed by PORT. Radiation-induced fibrosis volume can be used as a quantitative imaging marker in assessment of radiation-induced pulmonary injury.