Radiotherapy for Breast Cancer and Pulmonary Toxicity Outside the Radiation Field

To the Editor:

We read with interest the report by Epler and Kelly¹ on post-breast cancer radiotherapy bronchiolitis obliterans organizing pneumonia. The authors reported that the post-radiotherapy lung injury usually developed during the 12 months after completion of radiotherapy and was characterized by ground-glass opacities even in the nonirradiated lung, and they also indicated that age and cigarette smoking were 2 of the 3 risk factors.¹

We would like to share our experience. At our institution, we practice intensity-modulated radiation therapy using TomoTherapy. In this treatment method, we have treated 2 patients who have had both ground-glass opacities and consolidations appear outside the radiation field. These 2 patients were both women, aged 64 y and 50 y. One had a history of smoking, while the other did not. After partial resection of stage I breast cancer, they had chest wall 50 Gy irradiation. Opacities appeared 2 months after the end of irradiation in one patient, and at 5 months in the other patient. They have been followed to 24 months and 44 months, respectively. When computed tomography examinations were repeated at intervals of several months to half a year, there was no sign of scarring where the opacities had been identified. For this reason, we described these opacities as “moving around” or “migratory.” Up to now, these patients were not prescribed systemic corticosteroids because they had no deterioration in respiratory status or volume loss in the lungs. Considering previous reports^2-4 and our experience together, we need to pay attention to the following 4 points: (1) the presence of patients with migratory opacities to both lungs in the irradiated and nonirradiated field after irradiation for breast cancer; (2) the existence of patients whose migratory opacities did not change to “fibrosis with volume loss”; (3) the existence of patients with long-term migratory opacities; and (4) the presence of patients whose respiratory status did not worsen without corticosteroids.

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