Axillary surgery after neoadjuvant treatment and pathologic complete nodal response
B-51, tumor, breast cancer, Her2-positive, ypN0
TUMOR, TRIPLE-NEGATIVE BREAST CANCER, BREAST CANCER
Advances in systemic therapy approaches for breast cancer have led to multiple neoadjuvant regimens, especially for Her2-positive and triple-negative breast cancer, showing pathologic complete response (pCR) rates of 58–67% [Considering the omission of ALND in patients undergoing neoadjuvant systemic treatment (NST), the ACOSOG Z1071, the SENTINA trial, as well as the SN FNAC study provided information on the false-negative rate of the SLNB, which was 12.6%, 14.2%, and 8.4% (13.3% if considering isolated tumor cells as node-negative), respectively [Another technique is the MARI (marking axillary lymph nodes with radioactive iodine seeds) procedure, marking the largest tumor-positive LN (MARI node) pre-NST, which is subsequently selectively removed after NST. Furthermore, patients are staged with a FDG PET/CT before NST and classified to either <4 (cALN <4) or ≥4 (cALN ≥4) FDG-avid axillary lymph-nodes. After NST, patients are classified into ypMARI negative, or ypMARI positive. According to the study protocol, patients with less than 4 FDG-avid LN in pre-NST staging, and a negative MARI LN receive no further treatment. Those patients with either cALN ≥4 + ypMARI negative, or cALN <4 + ypMARI positive receive axillary radiotherapy, and patients with cALN ≥4 + ypMARI positive receive ALND. This method showed a FNR of 7% with a median of one removed LN, and a potential ALND-avoidance in up to 82% of patients, resulting in potential undertreatment in 3% [Ongoing studies investigating oncological outcomes in cN + patients converting to ypN0 includes the OPBC-04 OMA study examining recurrence-rates in patients undergoing SLNB vs. TAD. The NSABP B-51 trial includes patients with T1-T3 breast cancer, presenting with histologically confirmed cN1, who undergo NST, breast conserving surgery or mastectomy, and are ypN0 after ALND, SLNB + ALND, or SLNB. These patients are randomized to receive either whole-breast irradiation (WBI), WBI and RNI after BCS, chest wall irradiation and RNI after mastectomy or no adjuvant radiotherapy (NCT01872975) [