Ten-year report on axillary recurrence after negative sentinel node biopsy for breast cancer from the Swedish Multicentre Cohort Study

Background: The omission of axillary lymph node dissection (ALND) in patients with breast cancer with a negative finding on sentinel node biopsy (SNB) has reduced armmorbidity substantially. Early follow-up reports have shown the rate of axillary recurrence to be significantly lower than expected, with a median false-negative rate of 7 per cent for SNB. Long-term follow-up is needed as recurrences may develop late. Methods: The Swedish Multicentre Cohort Study included 3518 women with breast cancer and a clinically negative axilla, in whom SNB was planned. ALND was performed only in patients with sentinel node metastasis. Twenty-six centres contributed to enrolment between September 2000 and January 2004. The primary endpoint was the axillary recurrence rate and the secondary endpoint was breast cancer-specific survival, calculated using Kaplan-Meier survival estimates. Results: Some 2216 sentinel node-negative patients with 2237 breast cancers were analysed. The median follow-up time was 126 (range 0-174) months. Isolated axillary recurrence was found in 35 patients (1.6 per cent). High histological grade and multifocal tumours were risk factors for axillary recurrence, whereas the removal of more than two sentinel nodes decreased the risk. Fourteen (40 per cent) of 35 patients died as a consequence of axillary recurrence. Conclusion: The risk of axillary recurrence remains lower than expected after a negative finding on SNB at 10-year follow-up. Axillary recurrences may occur long after primary surgery, and lead to a significant risk of breast cancer death.