Abstract
BACKGROUND: Radiation pneumonitis may be induced in patients undergoing radiotherapy for lung cancer. However, the histological effects of radiotherapy on the healthy lung tissue are unknown. Transbronchial biopsy (TBB) has shown safety and efficacy in monitoring lung parenchyma. The aim of our study was to assess histological changes of the healthy lung parenchyma after radiotherapy by means of TBB. PATIENTS AND METHODS: A total of 12 patients with lung cancer necessitating radiation therapy participated the study. Serial TBBs were obtained from the opposite to the tumor lung tissue before, just after RT, and at 6 months post-irradiation. Evaluation of each specimen was based on the presence of congestion, inflammation, hemorrhage and fibrosis. RESULTS: A significant increase of interstitial fibrosis (thickness) and congestion was observed between the pre-RT point and after the completion of RT (P=0.048), as well as between the pre-RT point and at 6 months from RT (P=0.014). Six patients (50%) showed intra-alveolar fibroblastic growth after RT. No patient showed clinical or radiographic findings of pneumonitis. CONCLUSIONS: Our study shows that, even in the absence of clinical or radiographic findings, the lung parenchyma suffers early histological lesions after radiation therapy, as monitored by serial TBBs.