), there is a chance that any tumor spread to the armpit nodes will get cleared by the
chemotherapy. Hence, doing the sentinel node biopsy after neoadjuvant
chemotherapy may not yield reliable results - negative sentinel nodes may have been originally positive for cancer, but those cancer cells might have been killed off by the chemotherapy. If neoadjuvant chemotherapy is performed, it might be better to sample more nodes during surgery, instead of just doing sentinel node biopsy.