By David LiuA new study in the June 2011 issue of Nihon Kokyuki Gakkai Zasshi suggests that postoperative radiation therapy together with use of tamoxifen may boost risk of organizing pneumonia in breast cancer patients."Bronchiolitis obliterans organizing pneumonia (BOOP) is an inflammation of the bronchioles (bronchiolitis) and surrounding tissue in the lungs. It is an non infectious pneumonia", according to wikipedia.The study led by T Kishikawa of National Nagasaki Medical Center in Japan and colleagues reported three cases of organizing pneumonia, which occurred in the breast cancer patients after postoperative radiotherapy.The researchers said the cases of organizing pneumonia have been on the rise and they believed based on the three cases that tangential radiation therapy and adjuvant tamoxifen indicated to treat breast cancer patients may be the cause of the organizing pneumonia in these cases.