Neo-Adjuvant Chemotherapy in Luminal, Node Positive Breast Cancer: Characteristics, Treatment and Oncological Outcomes: A Single Center's Experience.

Objective: Neo-adjuvant chemotherapy (NAC) is the treatment of choice for patients with locally advanced breast cancer (BC). In luminal-like BC, the decision to administer NAC remains controversial. The purpose of this study was to describe the clinical characteristics, treatment, and oncological outcomes of luminal-like, node positive, BC patients treated with NAC, and to identify independent predictive factors for treatment.

Materials and methods: All consecutive patients with luminal-like, node positive BC who underwent NAC were retrospectively reviewed. Pathologic complete response (pCR) was defined as no invasive or in situ residual tumor in both breast and axillary nodes (ypT0N0).

Results: A total of 205 luminal-like, node positive BC patients underwent NAC. Overall, 34 (16.6%) patients showed pCR, 86 (42.0%) patients underwent breast-conserving surgery (BCS), 119 (58.0%) patients underwent mastectomy, 130 (63.4%) patients underwent axillary lymph node dissection (ALND) without prior sentinel lymph node biopsy (SLNB), and 75 (36.6%) patients underwent breast surgery plus SLNB. Pathologic CR to NAC (29.1% vs 7.6% if no pCR, odds ratio = 2.866, 95% confidence interval = 1.296-6.341, p = 0.009) was found to significantly increase the probability to receive BCS. There was no significant difference in terms of disease-free and overall survival between patients with luminal-like, node positive BC receiving BCS or mastectomy (p = 0.596, p = 0.134, respectively), and ALND or SLNB only (p = 0.661, p = 0.856, respectively).

Conclusion: Luminal-like, node positive BC presents low pCR rates after NAC. Pre-operative chemotherapy increases the rate of BCS. Pathologic CR has emerged as an independent predictive factor for BCS. In patients with axillary pCR, SLNB is an acceptable procedure not associated with worse oncological outcomes.