Radial scar on image-guided breast biopsy: is surgical excision necessary?

Radial scar's stellate appearance may mimic carcinoma mammographically and histologically. Management of radial scar (RS) found on breast core needle biopsies (CNB) ranges from excision to clinical observation due to the variation in reported upgrades to malignancy at surgical excision. We examined the upgrade rate in patients with RS detected on CNB at our institution and reviewed the current literature. A retrospective study was conducted of all cases with RS diagnosed on CNB between December 2006 and March 2017 at our institution. Inclusion criteria were patients with "pure" RS and RS associated with high-risk lesions (HRL). Upgrade was defined as invasive or non-invasive cancer in the excisional biopsy. 157 cases were identified with RS on CNB, and 122 cases met inclusion criteria. Of these 122 cases, 91 (75%) had pure RS on CNB while 31 (25%) had associated atypia or HRL. 81 (66%) of patients proceeded to excisional biopsy and 41 (34%) did not. Two patients (1.6% of total) were found to have a low-grade invasive ductal carcinoma (0.6 and 0.8 cm) upon surgical excision. None of the remaining 120 patients developed an ipsilateral breast cancer with a mean of 32.3-month follow-up. We found a very low upgrade rate to breast cancer when RS was found on CNB with or without associated HRL. Our results are consistent with other reported series. Our data do not support surgical excision for RS but rather close clinical follow-up for patients with RS on CNB.