Impact of axillary lymph node dissection on breast cancer outcome in clinically node negative patients: a systematic review and meta-analysis.

BACKGROUND: The regional lymph node control and survival impact of axillary dissection in breast cancer has been the subject of multiple randomized trials, with various results. This study reviews and conducts a meta-analysis of contemporary trials of axillary dissection in patients with early stage breast cancer.
METHODS: A systematic MEDLINE review identified 3 randomized trials published between January 2000 and January 2007 of axillary dissection versus no dissection in clinically lymph node negative early stage breast cancer patients. A fourth trial of axillary radiotherapy versus no axillary treatment was also identified and included in this review. Meta-analyses were performed for survival, axillary recurrence, metastatic disease, and ipsilateral breast recurrence.
RESULTS: All trials reported a higher rate of axillary recurrence (1.5%-3%, median follow-up 5-15 years) in the absence of axillary dissection or radiotherapy. Overall survival was similar with and without definitive axillary treatment in 3 of the 4 trials, with an increased rate of nonbreast cancer-related death in the observation arm of the fourth trial. Meta-analyses found no significant difference in overall survival (odds ratio [OR] 1.55; 95% confidence interval [CI], 0.74-3.24), metastases (OR 0.91; 95% CI, 0.65-1.29), or ipsilateral breast recurrence (OR 1.11; 95% CI, 0.68-1.83) associated with axillary treatment. A significantly lower rate of axillary recurrence was seen after lymphadenectomy (OR 0.28; 95% CI, 0.11-0.73, P<.01).
CONCLUSIONS: Axillary dissection does not confer a survival benefit in the setting of early stage clinically lymph node negative breast cancer. Although the rate of axillary failure was increased in the absence of dissection, the absolute risk was found to be extremely low.