Breast hypoplasia following irradiation of the female breast in infancy and early childhood.

The occurrence and the degree of breast hypoplasia were studied in 129 women irradiated with ionizing radiation in infancy or childhood for hemangioma located in the breast region. The patients were born between 1934 and 1943 and were treated at Radiumhemmet before 4 years of age. Dosimetry was based on treatment data. The mean absorbed dose to the breast anlage was 2.3 Gy. Breast asymmetry was estimated by a mailed questionnaire to all patients and by a clinical examination of 53 patients living in Stockholm County. Breast hypoplasia on the treated side was reported by 57% of the patients and on the contralateral side by 8%. A breast hypoplasia exceeding 10% was found in 53% of the clinically examined patients on the treated side and in 9% on the contralateral side. The frequency and the severity of impaired breast development increased with the absorbed dose. The possibility of a threshold dose for the occurrence of breast hypoplasia could neither be established nor ruled out.