Can sentinel lymph node biopsy be omitted in patients with favorable breast cancer histology?

Background: The widespread use of sentinel lymph node biopsy (SLNB) to replace axillary dissection has broadened the indications for axillary staging in breast cancer. Recent studies have demonstrated a finite risk of lymphedema and sensory morbidity associated with SLNB. We undertook this study to determine whether SLNB could be omitted in clinically node-negative patients with favorable-histology breast cancer.

Methods: We conducted a retrospective review of a prospective database of SLNBs performed at Memorial Sloan-Kettering Cancer Center from 1996 to 2003 to determine the incidence of lymph node metastases by histological subtype. For the favorable subtypes, the patient's age, tumor size, estrogen receptor status, lymphovascular invasion, nuclear grade, and histological grade were compared by nodal status to determine their predictive value.

Results: A total of 196 cases with favorable breast cancer subtypes were identified with a 4.1% (8 of 196) sentinel lymph node (SLN) positivity rate. Each of the histological subtypes included patients with positive SLNs, with the exception of adenoid cystic (n = 4) and secretory (n = 1) breast carcinoma, which were quite rare in our series. When compared by nodal status, the patient's age, tumor size, estrogen receptor status, lymphovascular invasion, nuclear grade, and histological grade failed to predict those with positive SLNs.

Conclusions: Patients with favorable breast cancer histology have a small risk of axillary SLN metastases. The use of SLNB in these patients should be individualized, taking into consideration the small incidence of axillary metastases and the risks and benefits associated with the SLN procedure.