1. ¹Stem Cell Transplant Unit, National Cancer Center Hospital, Tokyo, Japan
2. ²Department of Radiology, National Cancer Center Hospital, Tokyo, Japan
3. ³Department of Medical Oncology, National Cancer Center Hospital, Tokyo, Japan
4. ⁴Department of Molecular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
5. ⁵Blood and Marrow Transplant Program, University of Michigan, Ann Arbor, MI, USA

Correspondence: Dr S Yoshihara, Department of Molecular Medicine, Osaka University Graduate School of Medicine, 2-2, Yamada-oka, Suita, Osaka 565-0871, Japan. E-mail: yoshihara@imed3.med.osaka-u.ac.jp

Received 19 May 2004; Accepted 24 February 2005; Published online 25 April 2005.

Abstract

Bronchiolitis obliterans (BO) is one of the most devastating complications after allogeneic stem cell transplantation (HSCT). However, its true pathogenesis is still to be elucidated. We conducted this study to find whether tissue damage due to high-dose chemo-radiotherapy is related to its pathogenesis. In all, 144 patients who received allogeneic HSCT between May 1999 and October 2001, and survived more than 80 days after transplant, were analyzed. Clinical course, pulmonary function tests, imaging studies including CT scan, and pathology results were reviewed. The overall incidence of BO was 9.7% (14/144). The cumulative incidence of BO at 2 years after transplant was 17% with myeloablative conditioning, and 2.3% with reduced intensity conditioning (P=0.024). Multivariate analysis showed that myeloablative conditioning was the only factor which affected the incidence of BO. Development of BO did not significantly affect the overall survival of patients. However, if they developed BO earlier than 200 days post transplant, the prognosis was significantly worse than if they developed it later than 200 days post transplant (P=0.003) or if they did not develop BO (P=0.002). Our results imply that tissue damage secondary to intensive chemo-radiotherapy may contribute to the pathogenesis of BO.