Total body irradiation with or without lung shielding for allogeneic bone marrow transplantation.

From June 1986 to June 1990, 64 patients with leukaemia (25 acute myelogenous leukaemia, 21 acute lymphoblastic leukaemia and 18 chronic myeloid leukaemia) undergoing marrow transplantation were randomized to receive cyclophosphamide (CY) and fractionated total body irradiation (TBI) without lung shielding (n = 33) or CY and fractionated TBI with lung shielding (n = 31, control group) as conditioning. Patients conditioned with TBI without lung shielding received a significantly higher total lung dose compared with the control group (p less than 0.0001). The 3-year leukaemia-free survival for patients receiving TBI without lung shielding is 54 +/- 18% versus 51 +/- 18% for patients receiving TBI with lung shielding (p = ns). There was no significant difference in the probability of leukaemia relapse (22 +/- 18% for TBI without lung shielding versus 24 +/- 18% for control group; p = ns). The probability of interstitial pneumonitis is 15 +/- 14% for TBI without lung shielding and 5 +/- 5% for TBI with lung shielding (p = ns). A higher incidence of lung fungal infection (15 versus 3%) and interstitial pneumonitis (12 versus 3%) has been documented in patients receiving TBI without lung shielding compared with the control group. The results indicate that higher radiation dose to the lung did not increase antileukaemic efficacy of TBI but seemed to be associated with the increased pulmonary toxicity.