Risk factors for radiation-induced lung toxicity in patients with non-small cell lung cancer who received postoperative radiation therapy

Background and purposeTo evaluate the risk factors for radiation-induced lung toxicity (RILT) from post-operative radiation therapy (PORT) in patients with non-small cell lung cancer (NSCLC).Material and methodsNinety NSCLC patients who received PORT with or without chemotherapy from November 2002 to March 2006 were retrospectively analyzed. Each individual's radiotherapy plans were reviewed to determine the percentage of the whole lung volume that received more than a specific dose of irradiation (Vdose). The endpoint was RILT of grade 2 or higher. Data of potential risk factors for RILT were extracted from the medical records and evaluated by logistic regression modeling, the t-test, and the Chi-square test.ResultsA total of 20 patients received pneumonectomy, while the remaining 70 received lobectomy. In the lobectomy group, 9 patients (10%) developed ≥grade 2 RILT. Among the clinical factors, only adjuvant chemotherapy was significantly correlated with RILT (p = 0.039). For lung dosimetric factors, V20 through V40 were all significantly higher in the RILT group than in the non-RILT group. In the lobectomy group, the incidence of RILT was 27.3% in patients who received adjuvant chemotherapy and whose V20 was greater than 20%. It was 9.7% in lobectomy patients with one of the risk factors, and 0.0% in those with no risk factors (p = 0.032).ConclusionsThe lung toxicity of PORT was found to be acceptably low. Adjuvant chemotherapy and lung dosimetric factors of V20–V40 were significantly correlated with RILT risk in NSCLC patients.