Incidence and impact of documented eradication of breast cancer axillary lymph node metastases before surgery in patients treated with neoadjuvant chemotherapy

Objective To determine the incidence and prognostic significance of documented eradic ation of breast cancer axillary lymph node (ALN) metastases after neoadjuva nt chemotherapy. Summary Background Data Neoadjuvant chemotherapy is the standard of care for patients with locally advanced breast cancer and is being evaluated in patients with earlier-stag e operable disease. Methods One hundred ninety-one patients with locally advanced breast cancer and cyt ologically documented ALN metastases were treated in two prospective trials of doxorubicin-based neoadjuvant chemotherapy. Patients had breast surgery with level I and II axillary dissection followed by additional chemotherap y and radiation treatment. Nodal sections from 43 patients who were origina lly identified as having negative ALNs at surgery were reevaluated and hist ologically confirmed to be without metastases. An additional 1112 sections from these lymph node blocks were obtained; half were stained with an antic ytokeratin antibody cocktail and analyzed. Survival was calculated using th e Kaplan-Meier method. Results Of 191 patients with positive ALNs at diagnosis, 23% (43 patients) were con verted to a negative axillary nodal status on histologic examination (media n number of nodes removed = 16) Of the 43 patients with complete axillary c onversion, 26% (n = 11) had N1 disease and 74% (n = 32) had N2 disease. On univariate analysis, patients with complete versus incomplete histologic ax illary conversion were more likely to have initial estrogen-receptor-negati ve tumors, smaller primary tumors, and a complete pathologic response in th e primary tumor. The 5-year disease-free survival rates were 87% in patient s with preoperative eradication of axillary metastases and 51% for patients with residual nodal disease after neoadjuvant chemotherapy. Of the 39 pati ents with complete histologic conversion for whom nodal blocks were availab le, occult nodal metastases were found in additional nodal sections in 4 pa tients (10%). At a median follow-up of 61 months, the 5-year disease-free s urvival rates were 87% in patients without occult nodal metastases and 75% in patients with occult nodal metastases. Conclusions Neoadjuvant chemotherapy can completely clear the axilla of microscopic dis ease before surgery, and occult metastases are found in only 10% of patient s with a histologically negative axilla. The results of this study have imp lications for the potential use of sentinel lymph node biopsy as an alterna tive to axillary dissection in patients treated with neoadjuvant chemothera py.