Mammographic changes following radiotherapy.

Fifty-seven patients with carcinoma of the breast were assessed with serial mammograms following local excision and radiotherapy. The mammographic appearances due to radiotherapy were categorised and the changes in these with the passage of time have been studied. Residual tumour was identified on the basis of remaining malignant-type microcalcification. Local recurrence was identified on mammography. The most useful signs were the development of a mass lesion and the increase or development of malignant-type microcalcification. Differentiation of radiotherapy changes from recurrence of carcinoma can be made when a reaction that is normally due to radiotherapy occurs to an inappropriate degree, or with inappropriate timing.