Background: After the publication of the Z0011 trial, the American Society of Clinical Oncology published an updated clinical practice guideline stating that clinicians should not recommend axillary lymph node dissection (ALND) for early-stage breast cancer patients with the involvement of one or two sentinel lymph nodes (SLNs). However, these recommendations have been challenged because they were mainly based on data from limited studies. The aim of the current study is to systematically compare the real-world outcomes of SLN biopsy (SLNB) alone and SLNB + ALND in patients with early-stage breast cancers and limited positive SLN metastasis in the post-Z0011 era Patients and Methods: We searched articles in the PubMed, EMBASE, and Cochrane library databases. The primary endpoints were overall survival (OS) and disease-free survival (DFS). The secondary endpoints were recurrence rate and the incidence of lymphedema. Results: One randomized controlled trial and six retrospective studies with 8864 patients were retrieved. For patients with early-stage breast cancer with one or two SLN metastases, receiving SLNB alone showed no significant difference in OS, DFS, and recurrence rate compared with receiving SLNB + ALND. The incidence of lymphedema in patients who received SLNB alone was significantly lower than those who received SLNB + ALND (odds ratio 1.95, 95% confidence interval 1.02–3.71). Conclusions: Current real-world evidence proved that the Z0011 strategy is safe with respect to survival outcomes and effective in reducing the incidence of lymphedema. ALND should be avoided in patients with early-stage breast cancer with one or two SLN metastases in the post-Z0011 era.
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