Axillary recurrence after a negative sentinel node biopsy for breast cancer: Incidence and clinical significance

Background: Sentinel lymph node biopsy (SLNB) carries the inherent risk of approximately 5 % false-negative sampling. Undetected tumor-positive nodes of clinical importance are those that lead to axillary recurrence. This survey aims at clarifying the extent of this problem in current practice and literature. Methods: In a regional teaching hospital, 696 consecutive breast cancer patients underwent SLNB between January 1998 and July 2003, and data were entered in a prospective database. PubMed and the Cochrane library were searched for a systematic review of the literature. Thirteen studies dealt with the follow-up of a cohort of sentinel lymph node (SLN)-negative patients or presented a case report. Results: The SLN identification rate was 97.1 %. The SLN was tumor free in 439 (65 %) of the 676 patients. After a median follow-up of 26 months, axillary recurrence was detected in 2 of 439 patients 4 and 27 months after the SLNB. The incidence of clinically apparent falsenegative SLNB is 46 %. The systematic review resulted in 3184 SLNB-negative patients with a median follow-up of 25 months. Axillary recurrence occurred in eight patients after a median of 21 months. The axillary recurrence rate in the literature is 25 %. One third of these patients present with synchronous systemic metastases. Conclusions: Axillary recurrences after a negative SLNB occur, but at a much lower rate than would be expected on the basis of historical figures and the false-negative SLN findings. The natural history of axillary relapse after negative SLNB resembles the locoregional recurrence of breast cancer.