Short-Term Follow-Up Mammography in Breast Conservation Therapy Likely Leads to Unnecessary Downstream Workup: A Longitudinal Study

Abstract

Purpose: To analyze the effect of post-radiation therapy (XRT) mammographic timing and radiation technique in relation to additional downstream workup for 569 breast conservation therapy patients treated with adjuvant XRT after their initial surveillance mammogram (MMG).

Methods and materials: From January 2011 to December 2014, 569 breast cancer patients treated with breast conservation surgery and adjuvant XRT with a follow-up MMG were reviewed. Patients were stratified by the time interval until their first post-XRT MMG, and by XRT technique-whole breast (472), accelerated partial breast (96), conventional fractionation (373), hypofractionation (94), surgical cavity boosts (407), or no boost (66). The primary endpoint was further imaging after the initial MMG.

Results: Additional workup for those receiving an MMG within 3 months of completing XRT was 51% (73 of 143), compared with 40% (84 of 210) with MMG between 3 and 6 months and 34.5% (75 of 216) with MMG after 6 months (P=.04). Radiation boost to the postoperative bed was associated with further downstream imaging, whereas accelerated partial-breast irradiation and hypofractionated treatment were not.

Conclusions: Breast conservation therapy patients who underwent screening MMG before 6 months after completion of XRT were more likely to undergo downstream workup, including additional biopsies. Accelerated and hypofractionated radiation techniques were not associated with supplementary workup. Further study is needed to assess appropriate selection of high-risk patients and possible negative implications of earlier post-XRT screening MMG.