Factors predicting severe radiation pneumonitis in patients receiving definitive chemoradiation for lung cancer

Purpose: To identify factors that may predict for severe radiation pneumoni tis or pneumonopathy (RP), we reviewed a set of simple, commonly available characteristics. Methods and Materials: Medical records of 148 lung cancer patients with goo d performance status (ECOG 0-1) treated definitively with chemoradiation fr om 6/92-6/98 at the University of Pennsylvania were reviewed. Actuarial sur vival and the crude rate of severe radiation pneumonitis were determined as a function of several variables. Potential predictive factors examined inc luded age, gender, histology, stage, pulmonary function, performance status (0 vs. 1), weight loss, tumor location, radiation dose, initial radiation held size, chemotherapy regimen, and timing of chemotherapy. Univariate ana lysis (log-rank test) was performed for each variable. Multivariate analysi s was performed using linear regression. Results: Median survival for the entire cohort was 14.7 months. Four patien ts were inevaluable for pneumonitis due to early death from progressive dis ease. Of the remaining 144 evaluable patients, 12 (8.3%) experienced severe RP. The most significant factor predicting for severe RP was performance s tatus (p < 0.003). The risk of severe RP was 16% for PS-1 patients vs. 2% f or PS-0 patients. Women were significantly more likely to develop severe RP than men (p = 0.01). Among 67 patients for whom pre-radiation therapy pulm onary function data were available, forced expiratory volume of the lung in 1 second (FEV1) was also significant (p = 0.03). No patient suffering seve re RP had a pretreatment FEV1 > 2.0 liters. The median radiation dose was 5 9.2 Gy and median initial radiation held size was 228 cm(2). Neither radiot herapy factor predicted for RP. Other factors studied, including chemothera py drugs, and schedule, also were not significant predictors of severe RP. Conclusions: Pretreatment performance status, gender, and FEV1 are signific ant predictors of severe radiation pneumonopathy, at least when using conve ntional radiation fields and doses. Complex radiation dose-volume algorithm s that attempt to predict lung complication probabilities should probably i ncorporate these simply obtained clinical parameters. (C) 2000 Elsevier Sci ence Inc.