Success rates of re-excision after positive margins for invasive lobular carcinoma of the breast

Abstract

Rates of positive margins after surgical resection of invasive lobular carcinoma (ILC) are high (ranging from 18 to 60%), yet the efficacy of re-excision lumpReceptor subtypeectomy for clearing positive margins is unknown. Concerns about the diffuse nature of ILC may drive increased rates of completion mastectomy to treat positive margins, thus lowering breast conservation rates. We therefore determined the success rate of re-excision lumpectomy in women with ILC and positive margins after surgical resection. We identified 314 cases of stage I-III ILC treated with breast conserving surgery (BCS) at the University of California, San Francisco. Surgical procedures, pathology reports, and outcomes were analyzed using univariate and multivariate statistics and Cox-proportional hazards models. We evaluated outcomes before and after the year 2014, when new margin management consensus guidelines were published. Positive initial margins occurred in 118 (37.6%) cases. Of these, 62 (52.5%) underwent re-excision lumpectomy, which cleared the margin in 74.2%. On multivariate analysis, node negativity was significantly associated with successful re-excision (odds ratio [OR] 3.99, 95% CI 1.15–13.81, p = 0.029). After 2014, we saw fewer initial positive margins (42.7% versus 25.5%, p = 0.009), second surgeries (54.6% versus 20.2%, p < 0.001), and completion mastectomies (27.7% versus 4.5%, p < 0.001). In this large cohort of women with ILC, re-excision lumpectomy was highly successful at clearing positive margins. Additionally, positive margins and completion mastectomy rates significantly decreased over time. These findings highlight improvements in management of ILC, and suggest that completion mastectomy may not be required for those with positive margins after initial BCS.

Comprehensive Review of Molecular Mechanisms and Clinical Features of Invasive Lobular Cancer

“…Rates of BCS in early-stage ILC have increased by 11.6% from 1993 to 2003 [80], with accumulating evidence suggesting no significant long-term survival benefit for patients undergoing mastectomy [81,82]. Approximately 17% to 65% of patients with ILC require a second intervention, and re-excision lumpectomy is successful in achieving clear margins, particularly in those with node-negative disease [83,84]. The unique pathology of ILC leads to under-recognition of the extent of the disease in the breast on routine preoperative imaging and results in a more extensive surgery in order to obtain clear margins.…”

Estrogen Regulation of mTOR Signaling and Mitochondrial Function in Invasive Lobular Carcinoma Cell Lines Requires WNT4

“…As such, ILC is often difficult to detect via physical exam and mammography, resulting in a delayed diagnosis and more advanced disease at presentation. Additionally, ILC is associated with unique sites of metastasis [ 4 , 5 ] and more challenging surgical management [ 6 , 7 ]. Biomarkers for ILC are consistent with the hormone-dependent “luminal A” molecular subtype (e.g., estrogen receptor alpha (ERα, hereafter ER) and progesterone receptor positive, human epidermal growth factor receptor 2 (HER2) negative)) [ 1 , 3 ].…”

Lobular Breast Cancer: A Review

“…This is likely due to the challenges in accurately assessing disease extent in ILC. A more recent study exploring the success of re-excision of positive margins in women with ILC reported that while initial positive margins occurred in 37.6% of cases, clear margins were achieved in 74.2% of patients who underwent a re-excision lumpectomy ( 62 ). This suggests improvements in the surgical management of ILC, and that completion mastectomies may not be required in patients who have positive margins following their initial breast-conserving surgery.…”