Long-term outcomes of indeterminate breast (B3) lesions managed with vacuum-assisted excision

Abstract Background UK guidelines for indeterminate (B3) breast lesions recommend vacuum-assisted excision (VAE) over diagnostic surgery. However, there is little long-term follow-up published post VAE management. This study evaluates immediate and long-term outcomes of women with B3 lesions managed predominantly through radiological pathways. Methods Single-centre retrospective review of B3 lesions diagnosed between October 2011 and August 2017, evaluating outcomes following immediate management and subsequent breast cancer development during follow-up until February 2022. Results 513 women (median age 53yrs) were diagnosed with B3 lesions between October 2011 and August 2017. 391 (76.2%) had radiological management with second-line VAE, 48 (9.4%) had diagnostic excision and 74 (14.4%) had no second-line procedure. 54 lesions (10.5%) were upgraded to malignancy. Yearly mammography (atypia lesions, 5yrs) or three-yearly screening (non-atypia lesions) was offered to the remaining 459 women. 44/459 (9.6%) women had no mammographic follow-up (patient decision). Breast cancer occurred in 33 patients (7.2%), the majority (23/33, 69.7%) detected during imaging surveillance. 10 cancers (30.3%) occurred at the original B3 site. 5-year cumulative incidence of breast cancer was 6.3% (95% CI: 3.9%-8.7%). No significant difference in 5-year cumulative incidence of breast cancer between women with atypia (7.8%; 95% CI 4.3-11.2%) or without atypia (4.3%; 95% CI 1.1-7.4%) was demonstrated (p = 0.375). Conclusions Radiological management of B3 lesions is safe and effective. Following initial management, women with B3 lesions have a small risk of subsequent breast cancer, similar for lesions with or without atypia, most of which could be safely managed within normal screening pathways. Advances in Knowledge Vacuum-assisted excision can safely and effectively manage appropriate indeterminate breast lesions Risk of breast cancer following B3 diagnosis is low No statistically significant difference in subsequent breast cancer risk was demonstrated between B3 lesions with and without atypia