Effect of dose fractionation on pulmonary complications during total body irradiation.

Total body irradiation/Pulmonary complications/Dose fractionation. Total body irradiation (TBI) is an important component of conditioning regimens for Allogeneic bone marrow transplantation (BMT). Interstitial pneumonitis (IP) and other pulmonary disorders are known regimen-related complications. The incidence of IP is related to the dose rate and dose fractionation; however, there is a paucity of clinical data regarding the optimal dose fractionation. This retrospective study evaluated patients to determine the influence of dose fractionation during TBI in preparation for allogeneic BMT on the subsequent development of IP and other pulmonary complications. Fifty-six patients were treated with TBI followed by BMT at our institute. All patients received a total TBI dose of 12 Gy given in 6 fractions over 3 days or in 4 fractions over 2 days. The prevalence of unrelated donors in the 4-fraction group was higher than that in the 6-fraction group. The overall and freedom from progression rates for patients in the 4-fraction group were better than those for patients in the 6-fraction group, but the difference did not reach significance. Clinically significant lung complications occurred in 19 (10: infectious and 9: non-infectious diseases) of 33 patients in the 6-fraction group and 12 (7: infectious and 5: non-infectious diseases) of 23 in the 4-fraction group. There was no significant difference between the two groups. There was no significant difference in pulmonary complications between patients treated with a TBI dose of 12 Gy in 6 fractions over 3 days and patients treated with a TBI dose of 12 Gy in 4 fractions over 2 days.