Accuracy of sentinel lymph node biopsy in invasive lobular carcinoma of the breast.

Abstract

e12604 Background: The safety of the sentinel lymph node biopsy procedure (SLNB) in the surgical management of breast cancer relies upon a false negative rate (FNR) being less than 10%. The accuracy of SLNB in invasive lobular carcinoma (ILC), the second most common type of breast cancer, has not been evaluated. Because of high rates of false negative imaging and the diffuse growth pattern in ILC, less accurate pre-operative staging and a potentially unreliable lymphatic drainage pattern may impact the accuracy of SLNB in this tumor type. We therefore sought to characterize the accuracy of SLNB in a cohort of patients with ILC. Methods: We queried an institutional database of 707 patients with ILC and identified 196 patients who underwent SLN mapping with excision of both sentinel and non-sentinel nodes. A false negative was defined as having negative sentinel lymph nodes and a positive non-sentinel node. We calculated the FNR and sensitivity of SLNB and evaluated clinicopathologic variables. Results: Of 196 cases, 183 were clinically node-negative, 9 were clinically node-positive, and 4 had unknown clinical node status. Of the 183 clinically node-negative patients, 69 (37.7%) patients had node-positive disease at surgery. Overall, 7 of 196 cases had false negative SLNB, yielding an FNR of 8.97%. The sensitivity of SLNB was 91%. Patients with a false negative SLNB were significantly older than patients without (mean age 63 versus 54.7 years, p = 0.041). Significantly fewer sentinel and non-sentinel nodes were removed in women aged 50 years or older compared to those under 50 (1.9 vs. 2.5 sentinel nodes, p = 0.0158; 4.7 vs. 7.9 non-sentinel nodes, p = 0.0077). There were no differences in tumor receptor subtype, grade, stage, presence of lymphovascular invasion, or receipt of neoadjuvant therapy in those with a false negative SLNB compared to those without. Conclusions: The high rate of nodal positivity in clinically node negative patients highlights the challenges of clinical nodal assessment in ILC. Despite this, the SLNB procedure had a FNR that fell within the acceptable range, supporting its use in ILC. The relationship between number of sentinel nodes removed and FNR deserves further study, particularly in older women where extent of nodal surgery continues to decline.

Current and future diagnostic and treatment strategies for patients with invasive lobular breast cancer

“…112 Following sentinel lymph node biopsy, there is a 38% rate of nodal positivity in clinically node-negative patients, highlighting the challenges of clinical nodal assessment in ILC. 113…”

“…Prevalence of some genomic altera s might differ 31,42 Poten role of lipid metabolism in estrogen-independent growth of ILC 182 Long-term outcomes of prognos and pr ve v gene prognos tests Clinic ¹⁵⁶ Choice of surgery (mastectomy versus BCS; SLNB versus ALND) dependent on tumour and pa nt characteris 108,109 Mastectomy more o en carried out for ILC due t focality and tumour size 32,108,109 ALND more o en carried out due to higher nodal involvement 9,10,111,113 Emerging de-escala techniques…”

Impact of Histological Type and Grade on the Diagnostic Accuracy of Intraoperative Frozen Section for Detecting Breast Cancer Metastasis to Axillary Sentinel Lymph Nodes

“…They emphasized that in their study, 183 of 196 cases with positive SLNs were clinically node-negative. Moreover, cases with false-negative FS were older with a fewer number of SLNs removed than patients with a false-negative diagnosis [ 17 ]. These results further emphasize a need to evaluate more SLNs on FS than just a single lymph node.…”

What we learned in axillary management of breast cancer patients at the American society of clinical oncology (ASCO) 2020 virtual meeting? The EUBREAST point of view

“…One of the abstracts determined the accuracy of sentinel lymph node (SLN) mapping in patients with invasive lobular carcinoma (ILC) [1] . The false negative rate (FNR) was 8.97% and the sensitivity was 91%, comparing well with that reported for invasive ductal carinoma (IDC).…”