Long-Term Survival of Node-Positive Breast Cancer with Complete Nodal Response to Neoadjuvant Chemotherapy Treated with Sentinel Lymph Node Biopsy Alone: A Meta-Analysis

Introduction: There exist concerns regarding the use of sentinel lymph node (SLN) biopsy alone in node-positive breast cancer patients who have a clinical/radiological complete response in the axilla and are negative on histopathology after neoadjuvant chemotherapy (NACT). We hereby conducted a meta-analysis examining 5-year overall survival (OS) and disease-free survival (DFS) of such patients. Methods: PubMed, the Cochrane CENTRAL Library, Embase, Web of Science, and Scopus were searched up to July 30, 2024, for studies reporting survival data. OS and DFS were pooled in a meta-analysis. Subgroup analysis was conducted based on the location of the study, pre-NACT node assessment, and SLN mapping technique. Random-effects meta-regression was conducted for the following moderators: age, initial T3–4, initial N2–3, breast-conserving surgery, breast pathological complete response (pCR), number of SLN removed, adjuvant radiotherapy, endocrine therapy, and follow-up. Results: Sixteen studies with 5,249 patients were included. Meta-analysis showed that node-positive breast cancer patients showing nodal pCR after NACT and undergoing only SLN biopsy had a 5-year OS and DFS of 94% (95% CI: 92%, 96%) and 89% (95% CI: 87%, 92%), respectively. There was not much variation in the survival rate on sensitivity and subgroup analyses. Meta-regression showed that OS and DFS were higher in studies with a greater number of patients receiving endocrine therapy. Conclusion: Breast cancer patients with cN+ who achieve a complete clinical/radiological axillary response after NACT and subsequently become SLN biopsy negative may have high rates of DFS and OS after 5 years. Given the high degree of heterogeneity, results should be interpreted with caution. We do not recommend change in treatment plans given the high risk of bias and large heterogeneity in the patient population included in the studies. Only high-quality large multicentric randomized trials can provide better evidence.