The value of mammography after limited breast surgery and before definitive radiation therapy.

One hundred twenty consecutive patients who had breast-conserving surgery for cancer and were referred for definitive radiation therapy (RT) had a mammogram performed before starting RT. This was done to determine the presence of residual neoplasm or other abnormalities that may alter or delay the planned RT and are undetected by other means. It also was performed to provide a baseline for the diagnosis of postoperative changes and recurrence of disease on follow-up studies. In six (5%) patients, calcifications or masses were found that proved to be residual tumors. This led to reexcision in two, mastectomies in two, and a higher radiation booster dose to the tumor bed in two. Eight (6.6%) patients had postoperative hematomas larger than 4 cm in diameter, which delayed the start of RT by 2 to 3 weeks. In 39 (32%) patients, the pre-RT mammogram provided information considered to be helpful for the interpretation of post-RT mammograms. Such information may lead to a decrease in the number of diagnostic biopsies based on indeterminate mammographic findings. Therefore, a routine mammogram is recommended before RT is started.