E1337. Radial Scar Upgrade Rates Pre- and Post-Tomosynthesis Within a Tertiary Care Breast Imaging Center
Maine Medical Center
Spectrum Medical Group
Spectrum Medical Group
We compared the number of radial scars identified before and after the implementation of digital breast tomosynthesis (DBT) and assessed the relative post-surgical upgrade rate. We hypothesized there would be an increase in the overall number of radial scars identified with DBT, but the rate of surgical upgrade would be stable.
Materials and Methods:
Following IRB approval, the radiology reporting software system was queried to select radial scar cases from 2013–2015 and from 2018–2020, as DBT was adopted in 2016 at our National Accreditation Program for Breast Centers (NAPBC)-accredited breast center. With each case, the data were anonymized, and year of biopsy, core biopsy, and post-surgical pathology were recorded. We defined upgrade as a surgical pathology result with either ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), or invasive lobular carcinoma (ILC) that was not present on core biopsy.
There were a total of 33,930 2D mammograms performed between 2013 to 2015 and 32,628 DBTs performed between 2018 to 2020. There were 13 radial scars identified pre-DBT and 38 radial scars identified post-DBT. The average number of radial scars identified annually pre-DBT was 4.33 and post-DBT was 12.67. Eight radial scars met the criteria of upgrade, three pre-DBT, and five post-DBT. There was an average upgrade rate pre-DBT of 23% and post-DBT of 13%. Two sample unpaired t-test analysis between these two groups demonstrates a p = 0.23. There was a total of 12 core biopsies that had other atypia present (lobular carcinoma in situ or atypical ductal hyperplasia) with radial scar. Across our two groups, for core biopsies with atypia, the overall rate of upgrade at surgery was five of 12 (42%). For radial scars with no other atypia present on core biopsy, three of 39 (7.7%) were upgraded at surgery.
We identified more radial scars annually in the post-DBT era than in the pre-DBT era. There was no statistical difference between the rate of upgrade between our groups. If other atypia was found with radial scar on core biopsy, the rate of upgrade was higher than when no atypia was present. These data may be helpful in shared decision making with patients when weighing the risks and benefits of surgical excision. The study was limited by a small sampling date range and reported prevalence of radial scar.