[Clinical study of bronchiolitis obliterans organizing pneumonia (BOOP) primed by radiation for breast cancer].

Bronchiolitis obliterans organizing pneumonia (BOOP) primed by radiation therapy for the breast cancer (BOOP-RT/BC) has been recognized recently. In this study, we reported 9 such cases and discussed steroid therapy. Mean radiation dose and interval from completion of radiation therapy to the appearance of BOOP-RT/BC were 47.3 Gy and 5.6 months respectively. BOOP-RT/BC recurrence was observed by 5 episodes in 3 of 9 cases (recurrence rate was 33%). Steroid therapy showed a remarkable improvement in both primary and recurrent disease, and no residual symptom or BOOP shadow was detectable at the end of the observation except for shadows due to radiation fibrosis. All but one patient were prescribed prednisolone, with a mean initial dose of 32.5 mg/day and a mean treatment duration of 46.7 weeks. One patient improved without treatment. No case suffered from respiratory failure which needed mechanical ventilation or was motile. Considering these findings and the fact that almost all patients are middle aged or senior women who are susceptible to osteoporosis, we conclude that steroid therapy for BOOP-RT/BC should be carefully considered.