Changes in local pulmonary injury up to 48 months after irradiation for lymphoma and breast cancer

Purpose: To assess the recovery from early local pulmonary injury after irr adiation and to determine whether regional differences exist. Methods: For 110 patients treated for breast cancer or malignant lymphoma, single photon emission computed tomography (SPECT) perfusion and ventilatio n scans and CT scans were made before, 3, 18, and 48 months after radiother apy. Dose-effect relations for changes in local perfusion, ventilation, and density were determined for each individual patient using spatially correl ated SPECT and CT data sets, for each follow-up period. Average dose-effect relations for both subgroups were determined, as well as dose-effect relat ions for different regions. Results: In general, partial improvement of local pulmonary injury was obse rved between 3 and 18 months for each of the three endpoints. After 18 mont hs, no further improvement was seen. Patients with breast cancer and malign ant lymphoma showed a similar improvement (except for the perfusion paramet er), which was attributed to a recovery from the early radiation response a nd could not be explained by contraction effects of fibrosis of lung parenc hyma. No regional differences in radiosensitivity 18 months after treatment were observed, except for the dorsal versus ventral region. This differenc e was attributed to a gravity-related effect in the measuring procedure. Conclusion: For all patients, a partial recovery from early local perfusion , ventilation, and density changes, was seen between 3 and 18 months after radiotherapy. After 18 months, local lung function did not further improve (lymphoma patients). (C) 2000 Elsevier Science Inc.