Can Axillary Lymph Node Dissection be Omitted in Breast Cancer Patients with Metastatic Sentinel Lymph Nodes Undergoing Mastectomy? A Systematic Review and Meta-Analysis of Real-World Evidence

Background The omission of axillary lymph node dissection (ALND) in patients with breast cancer who have metastatic sentinel lymph nodes (SLNs) undergoing mastectomy remains controversial. This meta-analysis explored the clinicopathological factors affecting the selection of ALND and the influences of ALND on survival outcomes in patients receiving mastectomy with positive SLNs. Methods Eligible studies published prior to 31 December 2022 were selected by searching the Embase, Web of Science and PubMed databases. Pooled analyses were performed using the number of events for clinicopathological parameters and HRs with 95% CIs for survival outcomes including disease-free survival (DFS), overall survival (OS), distant recurrence-free survival (DRFS) and locoregional recurrence-free survival (LRFS). Results A total of 10 retrospective studies enrolling only breast cancer patients with limited SLN metastases (no more than 3 positive SLNs or micrometastatic SLNs) undergoing mastectomy were included. Performing ALND in mastectomy patients who had limited SLN metastases was significantly correlated with invasive ductal carcinomas, larger tumors, lymphovascular invasion, higher tumor grade, macrometastatic SLNs, more positive SLNs, extranodal extension, positive surgical margins, negative ER, administration of adjuvant chemotherapy and nonwhite race ( P < 0.05). However, performing ALND did not result in significantly longer OS, DFS, LRFS or DRFS ( P > 0.05) in these patients. Conclusion The present meta-analysis indicated that ALND may be safely avoided in patients with breast cancer who had limited SLN metastases undergoing mastectomy. Further well-designed randomized clinical trials are warranted to validate our results.