[Two cases of bronchiolitis obliterans organizing pneumonia (BOOP) induced radiotherapy after surgery of breast cancer]

We report two cases of bronchiolitis obliterans organizing pneumonia (BOOP) induced radiotherapy after surgery of breast cancer. One of the patients was a 58-year-old woman. She underwent a conserving surgery for bilateral breast cancers, and received radiation therapy to the remaining part of bilateral breasts. Two months after the termination of irradiation, cough, fever and general fatigue developed. We clinically diagnosed this case as BOOP after radiation therapy. After initiation of oral steroid therapy, the clinical symptoms and radiographic findings disappeared. Another patient was a 57-year-old woman. She underwent radical mastectomy for right breast cancer. A month after the operation, she suffered from local recurrence, so radiation therapy to the thoracic wall was performed. After irradiation, resection of the thoracic wall lesion was performed because of malignancy from local skin biopsy specimen. Two months after the termination of irradiation, cough, dyspnea and fever developed. We clinically diagnosed this case as radiation-induced BOOP by BAL and TBLB findings. After an initiation of steroid therapy, the clinical symptoms and radiographic findings disappeared. It is important to be aware of BOOP as a complication in the patient who was given radiation after surgery of breast cancer.