Symptomatic Radiation Pneumonitis in Elderly Patients Receiving Thoracic Irradiation

Purpose: Advanced age has been associated with increased risk of radiation pneumonitis. The purpose of this study was to examine the clinical and dosimetric predictors of radiation pneumonitis in elderly patients relative to younger patients treated with thoracic radiation therapy for lung cancer.

Methods: Two hundred fifty-six consecutive patients with stage I-III small cell and non-small-cell lung cancer treated with definitive radiation with or without concurrent chemotherapy, between 2004 and 2009, were reviewed. Pneumonitis was graded by using the Common Terminology Criteria for Adverse Events version 4. Clinical parameters and dosimetric variables were assessed in univariate and multivariate analysis to evaluate predictors of grade ≥2 pneumonitis in patients age ≥70 years and age <70 years.

Results: There were 99 patients age ≥70 and 157 patients age <70 years old. Pneumonitis occurred in 32 patients (grade 2 [22], grade 3 [7], grade 4 [3], grade 5 [1]). On multivariate analysis, the V5 Gy (P = .005) and age ≥70 years (P = .001) predicted for grade ≥2 pneumonitis, whereas angiotensin converting enzyme inhibitor use was associated with decreased risk (P = .02). Pneumonitis grade ≥3 occurred in 10% (n = 10/99) of patients age ≥70 years and in 1% (n = 1/157) of patients <70 years (P = .001). In patients with a V20 Gy >31%, the incidence of grade ≥3 pneumonitis was 33% (n = 4/12) in elderly patients compared with 2% (n = 1/44) in younger patients (P = .005).

Conclusions: Elderly patients were observed to have an increased risk of symptomatic pneumonitis. Radiation dose parameters remain useful in this population; however, the threshold for clinically acceptable pneumonitis may be lower than in younger patients. angiotensin converting enzyme inhibitors use may mitigate radiation pneumonitis.