M. Witten1, L. Camp1, L. Aguilera1, L. Teng1, F. Philp1, B. Klepchick1, W. Poller1, T. Julian1, M. Cowher1 1Allegheny General Hospital,Breast Surgical Oncology,Pittsburgh, PA, USA
Introduction:
Our goal is to compare unnecessary downstream work-up for suspicious findings in ipsilateral surveillance mammography at 6 vs 12 months following breast conservation therapy (BCT).
Methods:
A retrospective review of our tumor registry captured 1956 low-risk patients with stage 0-III breast cancer from Jan 2011 to Dec 2014. Patients who had a complete mastectomy or incomplete data (n= 540) were excluded. Of 1416 patients undergoing BCT, 820 had data for analysis and were divided into two groups: follow-up mammograms at 4-9 months (group A;n= 547) and 10-20 months (group B;n=670); 397 patients had data at both timepoints. The number of callbacks for suspicious findings leading to downstream work-up, as well as recurrence rates, were compared between groups. Patient radiation exposure and cost of imaging were determined.
Results:
Groups were well-matched for age, tumor size and grade. A significant number of callbacks was observed in group A compared to group B (40% vs 34%; p≤0.05) leading to additional imaging with non-suspicious findings in more patients at the 6 mo timepoint. Additional views did not result in a significant increase in ipsilateral breast cancer recurrence detection between groups. Although the majority of patients in both groups received radiation therapy after BCT (73% vs 71%) the callback rates were not affected. The average radiation dose for a two view unilateral diagnostic mammogram (UDM) is approximately 0.4 mSv. Additional imaging adds 0.2-0.4 mSV for compression and/or magnification views resulting in a total of 0.6-0.8 mSv for patients who are called back for additional views. At our institution, patient cost is estimated to be $800 per UDM.
Conclusion:
Surveillance mammography at 6 months leads to a significant number of unnecessary callbacks and downstream imaging when compared to waiting for 10-20 months to image after BCT and eliminating the early UDM did not demonstrate a significant difference in detection of recurrence. Patient radiation dose and costs, including additional imaging views required after callbacks, would be significantly reduced.