Background: This study was designed to determine the incidence of late axillary recurrence (AR) in patients with negative sentinel lymph node biopsy (SLNB) and provide a comparison with SLNB positive patients who underwent axillary lymph node dissection (ALND).
Methods: Retrospective analysis of prospectively collected data on all breast cancer patients with negative SLNB from January 1997 to December 2000 was performed on a large, institutional database. Primary outcome was cumulative incidence of AR as a first event with/without concurrent local recurrence. SLNB positive patients who went on to ALND during the same timeframe were comparatively analyzed.
Results: A total of 1529 eligible patients were identified (median age 58 years, median tumor size 1.0 cm): 1297 (85 %) underwent lumpectomy; 1099 (75 %) received adjuvant radiation; and 874 (80 %) were estrogen receptor-positive. At 10.8 (range 0-16) years median follow-up, overall incidence of AR as a first event was low (n = 13). Cumulative incidence was 0.6 % [95 % confidence interval (CI) 0.2-0.9] 5 years after SLNB, and 0.9 % (95 % CI 0.4-1.4, 95 % CI 0.5-1.6) at 10 and 15 years. Late AR (>5 years after surgery) occurred in five patients. Median overall survival after AR was 4.6 years; median distant disease-free survival after AR was 3.8 years. Late AR was also low in a contemporaneous group of SLNB positive patients undergoing ALND. In this group, cumulative incidence of AR was 0.7 % (95 % CI 0.1-1.3) 5 years after surgery, and 0.8 % (95 % CI 0.2-1.5) at 10 and 15 years.
Discussion: Late AR after negative SLNB is rare; the majority of ARs are in the first 5 years after surgery. Prognosis after these events is poor. SLNB remains a safe and effective procedure for axillary evaluation in breast cancer.