Impact of neoadjuvant chemotherapy on axillary nodal involvement in patients with clinically node negative triple negative breast cancer.

Background: We evaluated the impact of Neoadjuvant Chemotherapy (NAC) versus primary surgery (PS) on axillary disease burden/surgery in clinically node negative Triple Negative Breast Cancer (TNBC).

Methods: Two hundred forty-three Stage I-III TNBC patients have enrolled on an IRB approved multisite prospective registry. Clinical and treatment information was collected.

Results: One hundred fifty-five patients with clinically node negative TNBC were identified. 47%, 49%, and 4% of patients had T1, T2, and T3 disease, respectively. Patients underwent PS (103/155, 66%) or NAC (52/155, 34%) at the discretion of treating physicians. 17% of PS and 0% of NAC patients were node positive at surgery (P=0.006). For T2 disease, 32% of PS and 0% of NAC patients were node positive at surgery (P=0.001). NAC patients had a lower chance of positive SLNB (0% vs. 12%, P=0.004) and undergoing ALND (2% vs. 22%, P=0.001) than PS patients.

Conclusion: In this clinically node negative TNBC cohort, all NAC-treated patients were node negative at surgery, whereas 17% of PS patients had involved axillary nodes. NAC should be considered for clinically node negative TNBC to reduce the extent of axillary surgery even if breast conservation is not planned.