Purpose: Clinical trials have shown that axillary lymph node dissection (ALND) can be avoided for many breast cancer patients with limited nodal involvement. However, whether its omission is safe for those with invasive lobular carcinoma (ILC) is still questioned. We sought to evaluate the impact of ALND on recurrence-free survival (RFS) by extent of nodal disease in patients with ILC.
Methods: We performed a retrospective, cross-sectional analysis of ILC patients treated between 1990 and 2019 at our institution. Patients underwent either breast conservation surgery (BCS) or mastectomy. We used univariate and multivariate statistics in Stata 14.2 to evaluate associations between extent of axillary surgery and time to recurrence stratified by nodal burden.
Results: Of 520 cases, 387 (78.4%) were node negative, 74 (14.9%) had 1-2 positive nodes, and 59 (11.4%) had three or more positive nodes. Most patients (93.3%) had hormone receptor-positive disease, and 94.8% had low or intermediate-grade tumors. The rate of ALND significantly decreased over time (p < 0.002). Using a multivariate model, there was no significant difference in RFS estimates based on receipt of ALND (HR = 0.53, 95% CI 0.17-1.64, p = 0.27), which also held true for patients with 1-2 positive nodes using a test of interaction (HR = 0.91, 95% CI 0.12-6.76, p = 0.92).
Conclusions: These findings support the safety of omitting ALND in selected patients with ILC. Further studies of axillary management in ILC and imaging tools to predict nodal involvement and therapeutic response are warranted.
Keywords: Axillary dissection; Invasive lobular carcinoma; Recurrence-free survival.