Mammographic changes following conservation surgery and radiation therapy for breast cancer

We studied 232 mammograms of 46 women who had conservation surgery and radiation therapy for localized breast carcinoma. The goals were 1) to define the time course of changes in skin thickness and stromal density resulting from therapy, 2) to determine whether age was associated with the degree of skin thickening, 3) to determine whether age or pretherapeutic stromal density were associated with the degree of increased posttherapeutic stromal density, and 4) to evaluate posttherapeutic focal lesions. Skin thickness increased by a mean of 3.1 mm in the 0-4-month posttherapeutic interval and gradually returned to a mean of .8 mm excess thickness by the 31-36-month interval; these changes were not significantly associated with patient age. Stromal density increase was maximum in the 5-8-month posttherapeutic interval and returned nearly to pretherapeutic levels by the 31-36-month interval; these changes were independent of age, but increase in stromal density was associated with low pretherapeutic stromal density (p < 0.005). Twenty-four percent of the patients developed focal posttherapeutic masses or microcalcifications; none of these was found to be malignant.