41 A Single-Centre Report on the Upgrade Rate of Complex Sclerosing Lesions of the Breast

Introduction

Radial scar or complex sclerosing lesion (CSL) of the breast is a benign and uncommon breast lesion characterized by stellate configuration of a fibroelastic core with entrapped ducts and lobules. The incidence of radial scar ranges from 0.6% to 3.7%. Despite benign pathology, the radiographic appearance of CSL can overlap or be indistinguishable from invasive or in situ carcinoma. The upgrade rate to malignancy at excision varies between 2% and 26%, with most studies reporting around 10%. Radial scar can coexist with other proliferative high-risk lesions, thereby contributing to the overall upgrade rate. The greatest risk factor for upgrade is the presence of atypia on core needle biopsy (CNB), with upgrade rates consistently around 25% when atypia is present. The objective of this study was to evaluate factors associated with the upgrade rate of CSL and subsequent impact on treatment.

Methods

A single-center retrospective study was performed with females over 18 with radiographic- and pathology-concordant diagnosis of radial scar between 2015 and 2020. We excluded patients with biopsy-proven invasive or in situ disease within 3 months prior to and after biopsy-proven radial scar. The clinicodemographic information collected about our population included menopausal status, personal and family history of malignancy, radiographic method of lesion detection, associated high-risk lesions, and adjuvant endocrine treatment. Primary outcome of upgrade rate was determined based on evidence of in situ or invasive disease on final pathology.

Results

In our institutional series, 82 patients were included, of whom 58 (70%) received surgery. After surgical excision, 1 case upgraded to ductal carcinoma in situ. Calcifications were seen in more than half of all lesions on CNB (53%). On CNB, only 10% of lesions had associated atypia and 7% had associated high-grade lesions (atypical ductal hyperplasia or lobular hyperplasia); interestingly, the lesion that did upgrade on excision had neither feature present at the time of CNB.

Conclusion

Upgrade rates of radial scar remain low regardless of the presence of atypia or associated high-risk lesions. Omission of routine excision of complex sclerosing lesions can be safely considered.

Author Affiliation:

Carolyn P. Smullin,¹ Julie Le,² Thomas E. Lawton,³ Jennifer L. Baker,²

¹David Geffen School of Medicine at UCLA, Los Angeles, CA
²Department of Surgical Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA

³Department of Pathology, David Geffen School of Medicine at UCLA, Los Angeles, CA