Top Line: What is the risk of nodal recurrence when sentinel lymph node biopsy alone is performed in patients with cN1 breast cancer that converts to cN0 after neoadjuvant chemotherapy?
The Study: ASCO recently published helpful guidelines for managing the axilla in breast cancer. An area of investigation is whether sentinel lymph node biopsy (SLNB) or axillary dissection (ALND) is necessary in patients with initially node positive disease that converts to clinically negative after neoadjuvant chemo (NAC). The data supporting SLNB in patients with initially cN+ disease is largely supported by studies that performed a full ALND after SLNB. This retrospective study analyzed a cohort of 610 patients from MSKCC with cN1 breast cancer who received NAC and then had SLNB alone. Of the total cohort, 91% converted to cN0 after NAC and underwent SLNB. Dual tracer mapping was performed, and if ≥ 3 SLN were dissected and all were negative, no further ALND was performed. Of those who were cN0 after NAC, 42% had SLNB alone. Important to note is that 88% received adjuvant radiation and 70% received regional nodal irradiation. Only 1 axillary recurrence occurred (<1%) in a patient who refused adjuvant RT, and no nodal recurrences occurred among those who received adjuvant RT. However, more prospective data is needed to determine when ALND and/or nodal radiation can be routinely omitted in women with clinically positive nodes at presentation.
TBL: The rate of nodal recurrence appears very low in this cohort of patients with cN1 breast cancer who convert to cN0, have SLNB with ≥ 3 negative nodes, and who routinely receive regional nodal irradiation. | Barrio, JAMA Oncol 2021