The Shift From Sentinel Lymph Node Biopsy Performed Either Before or After Neoadjuvant Systemic Therapy in the Clinical Negative Nodes of Breast Cancer Patients. Results, and the Advantages and Disadvantages of Both Procedures.

BACKGROUND

In patients with breast cancer who are candidates for neoadjuvant therapy (NAT), the timing of when to perform sentinel lymph node biopsy (SLNB) remains under discussion. The aim of this study was to compare the advantages and disadvantages of SLNB performed before and after NAT.

PATIENTS AND METHODS

One hundred seventy-two patients, T1c to T3 and N0 (clinically and according to ultrasound) candidates for NAT were included. We compared the outcomes of 2 groups: (1) 122 patients of whom SLNB was performed before NAT (pre-NAT) from December 2006 to April 2014; and (2) 50 patients with SLNB performed after NAT (post-NAT) from May 2014 to July 2016.

RESULTS

Both groups were homogeneous in baseline patient characteristics. The SLNB was positive in 50 patients [41.7%] (33 macrometastases [66%] and 17 micrometastases [34%]) versus 6 patients [12%] (5 macrometastases [83.3%] and 1 micrometastases [16.7%]) in pre- and post-NAT groups, respectively. The lymphadenectomy was performed in 34 patients [28.3%] versus 4 patients [8%], with an odds ratio of 3.48 (95% confidence interval, 1.3-9.3). The recurrences in the pre-NAT group after a median follow-up of 62 months were 12 systemic, 2 local and systemic, and none axillary. In the post-NAT group were no recurrences after a median follow-up of 16 months. Finally, SLNB after NAT reduces the delay in starting NAT from 24 to 14 days (medians; P < .001) and the identification of the SLNB was in 122 patients [100%] versus 49 patients [98%].

CONCLUSION

SLNB performed after NAT significantly reduces the rate of lymphadenectomies without any increase in recurrences at early follow-up. Furthermore, it allows systemic treatment to be started earlier without interfering in the SLNB identification rate.