Surgical Outcomes of Lobular Neoplasia Diagnosed in Core Biopsy: Prospective Study of 316 Cases

Abstract Purpose Management recommendations for lobular neoplasia (LN) including lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH) diagnosed in core biopsies (CB) are controversial. Our aim was to prospectively identify a subset of patients who do not require subsequent surgical excision (SE). Methods All patients diagnosed with LN on CB were enrolled and referred for SE. Cases with coexistent DCIS or invasive carcinoma were excluded. Cases with coexistent ductal atypia (LN-DA) and LCIS variants (LN-V) were separated from pure classic LN (LN-C). Dedicated breast pathologists and radiologists reviewed cases with careful imaging/pathology (IP) correlation. Results Of 13,772 total percutaneous breast CB procedures, 302 of 370 patients diagnosed with LN underwent SE. Upgrade to carcinoma was present in 3.5% (8/228) LN-C, 26.7% LN-V (4/15), and 28.3% LN-DA (15/53). Calcifications were the imaging target for 180/228 LN-C cases (79%); 7 were associated with upgrade (3.9%). Upgrades were rare for mass lesions (1/32) and MRI targeted lesions (0/14). Upgrades were similar for ALH and LCIS (3.4% vs. 4.5 %). During postsurgical follow up (mean = 34.5 months) 6.5% LN-C patients developed carcinoma in either breast. Conclusions While LN with non-classic morphology or with associated ductal atypia requires SE, this can be avoided in LN-C diagnosed on CB targeting calcifications when careful imaging/pathology correlation is applied. Until larger numbers are studied, excising LN-C diagnosed as masses or MRI-detected lesions may be prudent. Regardless of their selection for surgical management LN patients need close surveillance in view of their long-term risk of breast cancer.