OUTCOME OF SENTINEL LYMPH NODE BIOPSY POST NEOADJUVANT CHEMOTHERAPY IN CLINICALLY NODE NEGATIVE BREAST CANCER PATIENTS, CAN SENTINEL LYMPH NODE BIOPSY BE OMITTED IN SELECTED PATIENTS?

Abstract

Background: Sentinel lymph node biopsy (SLNB) remains an important component of axillary staging in clinically node-negative (cN0) breast cancer following neoadjuvant chemotherapy (NAC). However, the increasing frequency of pathological complete response (pCR), particularly in human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancer (TNBC), has prompted interest in response-guided de-escalation of axillary surgery to minimize treatment-related morbidity without compromising oncological safety.

Methods: This systematic review evaluated the diagnostic performance of SLNB, the prevalence of residual axillary nodal disease, the association between breast pCR and axillary pathological response, and the feasibility of selectively omitting SLNB after neoadjuvant systemic therapy. The review followed the principles of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Eligible prospective and retrospective studies involving patients with cN0 invasive breast cancer were assessed for pathological nodal outcomes, SLNB identification rates, diagnostic accuracy, recurrence, survival, and treatment-related morbidity. Quantitative synthesis was reported for studies providing relevant outcome data.

Results: Eighty-five reports were included in the systematic review, of which five studies contributed to the pooled analysis of 3,834 patients with HER2-positive or TNBC. Residual axillary nodal disease (ypN+) was identified in 83 patients (2.16%; 95% confidence interval [CI]: 1.70–2.63%), whereas 3,751 patients (97.84%) had ypN0 disease. Breast pCR rates were 45.0% in HER2-positive breast cancer and 37.2% in TNBC, while residual axillary nodal disease was reported in 1.6% of patients in each subtype. The pooled SLNB identification rate was 96% (95% CI: 95-97%), with sensitivity of 94% (95% CI: 92-97%), a negative predictive value of 98% (95% CI: 98-99%), and a false-negative rate of 6% (95% CI: 3-8%). The reviewed evidence also indicated lower morbidity following SLNB than axillary lymph node dissection, particularly regarding lymphedema, shoulder dysfunction, sensory disturbances, and postoperative pain.

Conclusion: The low prevalence of residual axillary disease in selected cN0 patients with HER2-positive and triple-negative breast cancer supports further investigation of response-adapted axillary management following neoadjuvant systemic therapy. Nevertheless, breast pCR cannot be considered a reliable substitute for pathological confirmation of axillary status, and the presence of residual nodal disease in a small proportion of patients remains clinically relevant. Routine omission of SLNB cannot be recommended on the basis of these findings alone; prospective trials with standardized response assessment and adequate long-term oncological follow-up are required to establish the safety of this strategy.