A comparison of single-dose and fractionated total-body irradiation on the development of pneumonitis following bone marrow transplantation

Purpose: A review of 132 consecutive patients who received bone marrow transplant for various malignancies was conducted to determine factors associated with increased risk in developing interstitial pneumonitis (IF) as the result of total body irradiation (TBI). Twenty-four patients were excluded because 22 did not receive TBI and two had insufficient records. Methods and Materials: Patients were conditioned with TBI and various drug regimens. Eighteen patients received a single 6.0 Gy dose of x-rays, The remaining 90 were treated with three doses of 3.33 Gy separated by 24 h. All patients were followed for at least 18 months for the purposes of determining the IP incidence, Results: Twenty-seven of these 108 (25%) patients developed IF; 19 (17.6%) died. The 2-year estimated incidence of IP was 24 and 18.6% for fatal IF. The etiology was determined to be idiopathic in 12 patients, the result of cytomegalovirus in 6 patients, and caused by a variety of other infectious organisms in 9 patients. We were unable to demonstrate a statistically significant increase in IP with age (adults vs. children), dose regimen, use of methotrexate for graft-vs.-host disease prophylaxis, the presence of acute graft-vs.-host disease, time from diagnosis to transplant, or transplant type (allogeneic vs, autologous). Conclusions: The incidence of fatal IP reported here is similar to that reported by other institutions utilizing hyperfractionated TBI protocols. Our data do not support the need for hyperfractionation to reduce the risk of IF.