Is a short-interval postradiation mammogram necessary after conservative surgery and radiation in breast cancer?

Abstract

To examine, in a retrospective study, whether the initial posttreatment mammogram offers any benefit to patients. Patients were selected who had radiation after breast-conservation therapy from 1995 through 2005 and had follow-up mammography at the University of California-Los Angeles (UCLA) within 1 year of completing radiotherapy. Results of the initial follow-up mammogram were analyzed to determine the yield of this initial mammogram. Between 1995 and 2005, 408 patients treated with breast-conserving therapy and radiation had follow-up mammograms at UCLA within 1 year of completion of radiation. Median age at radiation completion was 56.9 years. Median interval between radiation and the initial mammogram was 3.1 months. Ten patients were found to have suspicious findings on the initial postradiation mammogram, prompting biopsy, but only 2 were found to have recurrent cancer. None of those lesions were palpable. In both cases the recurrences were ductal carcinoma in situ. Thus, the yield of the initial postoperative mammogram as compared with physical examination findings is estimated at 0.49 recurrences detected per 100 mammograms performed (95% confidence interval 0.059-1.759). The yield of the initial postradiation mammography at UCLA seems to be low, and only noninvasive carcinomas were found. Our data support the rationale to avoid the initial short-interval postradiation mammography and evaluate patients at 12 months.