Change in Diffusing Capacity After Radiation as an Objective Measure for Grading Radiation Pneumonitis in Patients Treated for Non-Small-Cell Lung Cancer

• Published in: International journal of radiation oncology, biology, physics Vol. 83; no. 5; pp. 1573 - 1579
• Main Authors: Lopez Guerra, Jose Luis, M.D, Gomez, Daniel, M.D, Zhuang, Yan, M.D, Levy, Lawrence B., M.S, Eapen, George, M.D, Liu, Hongmei, M.S, Mohan, Radhe, Ph.D, Komaki, Ritsuko, M.D, Cox, James D., M.D, Liao, Zhongxing, M.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-08-2012; Elsevier
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; CARBON MONOXIDE; Carbon Monoxide - metabolism; Carcinoma, Non-Small-Cell Lung - drug therapy; Carcinoma, Non-Small-Cell Lung - physiopathology; Carcinoma, Non-Small-Cell Lung - radiotherapy; CHEMOTHERAPY; DIAGNOSIS; Diffusing capacity of lung for carbon monoxide; DOSES; Female; Hematology, Oncology and Palliative Medicine; Humans; Lung Neoplasms - drug therapy; Lung Neoplasms - physiopathology; Lung Neoplasms - radiotherapy; LUNGS; Male; Medical sciences; Middle Aged; NEOPLASMS; Non-small-cell lung cancer; PATIENTS; Pneumology; PNEUMONITIS; Proportional Hazards Models; Pulmonary Diffusing Capacity - physiology; Pulmonary Diffusing Capacity - radiation effects; Radiation Pneumonitis - diagnosis; Radiation Pneumonitis - physiopathology; Radiation therapy; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; TOXICITY; Tumors of the respiratory system and mediastinum; Non-small-cell lung cancer; Diffusing capacity of lung for carbon monoxide; Radiation therapy; Histological grading; Human; Lung disease; Pneumonia; Respiratory disease; Lung cancer; Lung; Malignant tumor; non-small cell lung carcinoma; Radiotherapy; Cancerology; Treatment; Bronchus disease; Diffusing capacity; Carbon monoxide; Cancer
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2011.10.065

Purpose Scoring of radiation pneumonitis (RP), a dose-limiting toxicity after thoracic radiochemotherapy, is subjective and thus inconsistent among studies. Here we investigated whether the extent of change in diffusing capacity of the lung for carbon monoxide (DLCO) after radiation therapy (RT) for non-small-cell lung cancer (NSCLC) could be used as an objective means of quantifying RP. Patients and Methods We analyzed potential correlations between DLCO and RP in 140 patients who received definitive RT (≥60 Gy) with or without chemotherapy for primary NSCLC. All underwent DLCO analysis before and after RT. Post-RT DLCO values within 1 week of the RP diagnosis (Grade 0, 1, 2, or 3) were selected and compared with that individual’s preradiation values. Percent reductions in DLCO and RP grade were compared by point biserial correlation in the entire patient group and in subgroups stratified according to various clinical factors. Results Patients experiencing Grade 0, 1, 2, or 3 RP had median percentage changes in DLCO after RT of 10.7%, 13%, 22.1%, or 35.2%. Percent reduction in DLCO correlated with RP Grade ≤1 vs. ≥2 ( p = 0.0004). This association held for the following subgroups: age ≥65 years, advanced stage, smokers, use of chemotherapy, volume of normal lung receiving at least 20 Gy ≥30%, and baseline DLCO or forced expiratory volume in 1 second ≥60%. Conclusions By correlating percent change in DLCO from pretreatment values at the time of diagnosis of RP with RP grade, we were able to identify categories of RP based on the change in DLCO. These criteria provide a basis for an objective scoring system for RP based on change in DLCO.