Targeted axillary dissection after neoadjuvant chemotherapy for highly selective patients with initial cN1 breast cancer:A single-center prospective trialOACSTPCDMEDLINE

Background:Sentinel lymph node(SLN)biopsy is gradually accepted as the standard of care in breast cancer patients with down-staged axillary disease after neoadjuvant chemotherapy(NAC).However,it is still difficult to precisely define pre-NAC clinical node-positive(cN1)and post-NAC clinical node-negative(ycN0).This prospective single-center trial was designed to evaluate the feasibility and accuracy of standard targeted axillary dissection(TAD)after NAC in highly selective pre-NAC cN1 patients(not considering ultrasound-based axillary ycN staging). Methods:This prospective trial included patients with initial pre-NAC cT1-3N1M0 invasive breast cancer but with a rigorous definition of cN1 from the Affiliated Cancer Hospital of Zhengzhou University.When NAC was effective(including complete and partial responses)and preoperative axillary palpation was negative,preoperative ultrasound-based axillary staging was not considered,and all patients underwent TAD followed by axillary lymph node(LN)dissection.The detection rate(DR)and false-negative rate(FNR)of TAD were calculated. Results:A total of 82 patients were included,and 77 of them were eligible for data analysis.The DR for TAD was 94.8％(73/77).There were 26 patients with one abnormal LN at the time of diagnosis based on ultrasound,45 patients with two,and 2 patients with three.One patient had one TAD LN,four patients had two TAD LNs,and 68 patients had three or more TAD LNs.Preopera-tive axillary palpation yielded negative results for all 73 patients who successfully underwent TAD.Preoperative ultrasound-based ycN0 and ycN+conditions were detected for 52 and 21 cases,respectively.The FNR was 7.4％(2/27)for standard TAD(≥3 SLNs),which was lower than that of all successful TAD(≥1 SLN;10.0％,3/30). Conclusions:In rigorously defined pre-NAC cN1 breast cancer patients,standard TAD is feasible for those with negative axillary palpation after NAC,and FNR is also less than 10％.Registration:chictr.org.cn,ChiCTR2100049093