Clinical predictive factors for radiation pneumonitis and pulmonary fibrosis during split course concurrent chemoirradiation for locally advanced non-small cell lung cancer

Purpose: We sought to identify factors predictive of development of radiation pneumonitis and pulmonary fibrosis following split course concurrent chemoirradiation for locally advanced non-small cell lung cancer (LA-NSCLC).Methods and Materials: We reviewed records of 108 patients treated with regimen of split course radiotherapy (median 60 Gy in 30 fractions) and concurrent chemotherapy for stage IIIa/IIIb NSCLC. Fisher's Exact Test and Paired Student T Test were performed to identify factors predictive of development of any pulmonary toxicity (pneumonitis or fibrosis of any grade) and severe pulmonary toxicity (grade 3 or higher pneumonitis, grade 2 or higher fibrosis).Results: 56 patients (51.2%%) developed any toxicity; 22 patients (20.4%) developed severe toxicity. The following predictive factors were identified for any and severe pulmonary toxicity, respectively: reactive airway disease (RAD), age, RV % expected (EXP), PEF %EXP, FEV1/FVC ratio, smoking status; and RAD, FEV1 %EXP, FVC %EXP, FEV1/FVC %EXP, RV %EXP, FEF25/75 %EXP, PEF %EXP, S-GAW %, FEV1, FVC, and FEV1/FVC .Conclusions: Our overall rates of any and severe pulmonary toxicity are acceptable. History of RAD and active smoking are protective, whereas patients with severe COPD have increased risk. A trend was seen toward improved outcomes with the use of prophylactic steroid control medication. These results should be confirmed in the context of a prospective study.