Sentinel node biopsy performance after neoadjuvant chemotherapy in locally advanced breast cancer: A systematic review and meta-analysis

Abstract

The use of sentinel node biopsy (SNB) after neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer is debated. Our aim was to quantitatively review the available evidence on the performance of SNB after NAC in patients with locally advanced breast cancer. We performed a systematic review (by searching the PubMed, Cochrane and Scopus databases) and random effects meta-analysis to investigate on the feasibility and accuracy of SNB in these patients. The two outcomes of interest were the sentinel node identification rate (SIR) and the false negative rate (FNR). Sensitivity analysis and meta-regression were used to investigate the potential sources of between-study heterogeneity. We retrieved 72 eligible studies enrolling 7,451 patients. Upon meta-analysis, summary SIR resulted 89.6% [95% confidence interval (CI): 87.8-91.2; heterogeneity I2: 76.9%], which poorly compares with the 95% SIR observed in some recent series of early breast cancer. The summary FNR resulted 14.2% (CI: 12.5-16.0; heterogeneity I2: 29.1%), which was significantly higher than the 8-10% reference value. Considering an average post-NAC lymph node positivity rate of 50%, the downstaging due to false negative SNB would occur in 7/100 patients (with an excess error rate of 2-3/100 as compared to the early-stage setting). No plausible source of between-study heterogeneity was found. Based on the largest series of studies ever meta-analyzed, our findings highlight the limits of SNB performance in this population, where the impact of SNB on patient survival is still to be defined. What's new? The use of sentinel node biopsy (SNB) to determine whether a tumor has spread into the lymphatic system has revolutionized the surgical management of early breast cancer. But whether SNB also benefits patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy remains unknown. Here, meta-analysis of existing evidence shows that SNB performs less well and is less accurate in the setting of locally advanced disease. Potential misdiagnosis with SNB in this setting could result in incomplete lymph node dissection and incorrect downstaging of disease. More information is needed, however, to fully assess SNB in locally advanced disease.