Can angiotensin-converting enzyme inhibitors protect against symptomatic radiation pneumonitis?

This study was designed to determine whether patients taking angiotensin-co nverting enzyme (ACE) inhibitors while receiving radiation therapy for lung cancer are protected from developing symptomatic radiation pneumonitis, Th e records of 213 eligible patients receiving thoracic irradiation for lung cancer with curative intent at Duke University Medical Center from 1994-199 7 were reviewed. Of the 213 patients, 26 (12.2%) were on ACE inhibitors (us ually for the management of hypertension) during radiotherapy (group 1); th e remaining 187 patients (group 2) were not. Patients were irradiated, with fields shaped to protect normal tissues, with total doses of 50-80 Gy. Aft er treatment, patients were generally followed every 3 months for 2 years, then every 6 months thereafter. Symptomatic radiation pneumonitis was score d according to modified National Cancer Institute Common Toxicity Criteria (i.e., radiographic changes alone were not sufficient for the diagnosis of pneumonitis). There was no difference in the incidence of pneumonitis betwe en the two groups (P = 0.75). Fifteen percent of the patients on ACE inhibi tors (group 1) developed symptomatic radiation-induced lung injury compared to 12% of the patients not receiving these drugs (group 2). Although patie nts in group 1 tended to develop pneumonitis slightly sooner than did patie nts in group 2, this difference also was not significant (P = 0.8). Within the dose range prescribed for treating hypertension, ACE inhibitors do not appear to either decrease the incidence or delay the onset of symptomatic r adiation pneumonitis among lung cancer patients receiving thoracic irradiat ion. (C) 2000 by Radiation Research Society.