Feasibility, accuracy and prognosis of sentinel lymph node biopsy before neoadjuvant therapy in breast cancer. A prospective study.

BACKGROUND AND OBJECTIVE: It remains controversial whether sentinel lymph node biopsy (SLNB) should be performed before or after neoadjuvant therapy (NAT). We aimed to evaluate the feasibility and accuracy of SLNB before NAT at a single institution, and to determine its relation to patient prognosis.

METHODS: A prospective study of T1c-T2-T3 N0 breast cancer patients, after ultrasound examination, who underwent SLNB prior to NAT. Overall, disease-specific and disease-free survival were calculated by Kaplan-Meier curves.

RESULTS: SLNB before NAT was performed in 123 patients from December 2006 to May 2014. The identification rate was 100%. SLNB was positive in 42.3% of cases (27.6% macrometastases). NAT was chemotherapy in 88.6% of cases and endocrine-therapy in 11.4%. Lymphadenectomy was avoided in 72.4% of cases. Median follow-up was 40 months (range 8-100). Overall and disease-free survival was 90.2% and 88.6% respectively.SLN involvement was not related to patient outcome (p 0.72); however there were significant differences in survival according to molecular-like subtypes (p < 0.025) and NAT response (p < 0.0001).

CONCLUSIONS: SLNB prior to NAT is an accurate method of axillary staging associated with a high identification rate. It avoided lymphadenectomy in more than 70% of patients. SLN involvement did not worsen the prognosis in our cohort.