D. I. Hoffman1, P. J. Zhang2, J. Tchou1,3 1Perelman School of Medicine at the University of Pennsylvania,Department Of Surgery,Philadelphia, PA, USA 2Perelman School of Medicine at the University of Pennsylvania,Department Of Pathology,Philadelphia, PA, USA 3Perelman School of Medicine at the University of Pennsylvania,Abramson Cancer Center, Rena Rowan Breast Center,Philadelphia, PA, USA
Introduction: Lobular carcinoma in situ (LCIS) found on core needle biopsy is a benign lesion that confers increased lifetime risk of breast cancer but generally does not require further surgery. In contrast, non-classic LCIS (NC-LCIS), which includes high-grade variants with pleomorphism or necrosis, warrants surgical excision. In patients pursuing breast-conserving surgery (BCS) for NC-LCIS, the need for wide surgical margins to prevent recurrence is controversial. We therefore characterized the surgical management and outcomes of women diagnosed with NC-LCIS at a large, academic medical center.
Methods: A retrospective database query was conducted to identify female patients seen at our institution from 2008–2018 with a biopsy diagnosis of NC-LCIS. Patients were excluded if NC-LCIS was diagnosed in the background of invasive breast carcinoma or ductal carcinoma in situ (DCIS). Clinicopathologic, surgical, and follow-up data were collected by chart review. Rates of upstage, re-excision, and recurrence were calculated.
Results: We identified 26 patients with NC-LCIS diagnosed on biopsy. The cohort was mostly white, the median age was 54 years (range 40–70), and half were postmenopausal. None were known carriers of breast cancer gene (BRCA) mutations, but 10 patients had a first-degree family history of breast cancer. Almost all (24/26) presented with an abnormal screening mammogram, 22 of which had suspicious calcifications. 80.8% (21/26) of patients initially pursued breast conservation, while 19.2% (5/26) underwent immediate mastectomy. At definitive surgery, 11.5% (3/26) were upstaged to DCIS or invasive carcinoma. Among 19 patients with a final diagnosis of NC-LCIS undergoing BCS, 47.4% (9/19) had at least one re-excision and five patients converted to completion mastectomy. In patients receiving BCS without completion mastectomy, 64.3% (9/14) had final surgical margins that were negative for NC-LCIS, while 35.7% (5/14) had close (<1mm) or positive margins. No recurrences in patients with negative margins at definitive surgery were observed. One patient with positive margins developed a local recurrence 8.3 years after surgery, and one patient with close margins did 2.2 years after surgery. All patients with a final diagnosis of NC-LCIS were alive at time of analysis with no evidence of progression to invasive carcinoma, mean follow-up time 4.5 years (range 20 days–10.5 years).
Conclusion: We presented the clinical outcomes of one of the largest single institution series of NC-LCIS, a rare diagnosis. In patients with a final diagnosis of NC-LCIS pursuing breast conservation, re-excisions are common and negative margins can be challenging. However, when negative margins are achieved, recurrence risk is low.
