CONSEQUENCES OF 2 DIFFERENT DOSES TO THE LUNGS DURING A SINGLE-DOSE OF TOTAL-BODY IRRADIATION - RESULTS OF A RANDOMIZED STUDY ON 85 PATIENTS

Purpose: To evaluate the incidence of lung complications and leukemia recurrences after two different doses to the lungs during total body i rradiation. Methods and Materials: Seventy-nine patients with acute le ukemia (AML or ALL) in first complete remission or chronic myeloid leu kemia in the chronic phase, five patients with high grade lymphoma, an d one with chronic lymphocytic leukemia were entered in the study. The y were given a single dose of total body irradiation (10 Gy over 4 h) with two different doses to the lungs (6 Gy or 8 Gy) prior to bone mar row transplantation. The median dose rate was 0.04 Gy/min. The median follow-up for both groups of patients was 24 months. Results: The actu arial 5-year overall survival rate was similar in both groups, 59% and 43% for patients given 8 Gy and 6 Gy to the lungs, respectively. The lung complication rate was similar in the two groups (28% vs. 22% for the 8 Gy and 6 Gy group, respectively); The actuarial leukemia recurre nce rate was significantly higher in the group of patients given 6 Gy to the lungs (25%) vs. 0% in the 8 Gy group. Interestingly, all recurr ences occurred in the group of patients who were given 6 Gy to the lun gs, who had acute leukemia, and no chronic graft vs. host disease (GVH D). Conclusions: Although the number of patients was not very large an d the follow-up relatively short, these findings suggest that a lower dose to the lungs could lead to an increased incidence of leukemia rec urrences due to a lower dose to the thoracic wall or to a lower incide nce of chronic GVHD.