A new era of neoadjuvant treatment with Pertuzumab: Should the 10-lymph node guideline for axillary lymph node dissection in breast cancer be revised?

BACKGROUND: Pertuzumab has improved pathologic complete response rates when compared with other chemotherapeutics in the treatment of HER-2 positive breast cancer patients. AIMS: We sought to determine if axillary lymph node dissections (ALNDs) yielding at least the national standard of 10 lymph nodes is lower in patients who received neoadjuvant pertuzumab. METHODS AND RESULTS: A retrospective database identified patients who underwent ALND for breast cancer. We compared the axillary lymph node retrieval rates in those who received or did not receive neoadjuvant pertuzumab. Of 139 breast cancer patients who underwent ALND, fewer than 10 axillary lymph nodes were found in 41.7% of patients who received neoadjuvant pertuzumab (P < 0.01) and 18.6% of patients who received neoadjuvant therapy without pertuzumab (P = 0.01). CONCLUSION: Neoadjuvant chemotherapy was associated with a significantly lower rate of "adequate" ALNDs as defined by current guidelines. The patient subset that received neoadjuvant pertuzumab was more likely to have fewer than 10 axillary lymph nodes retrieved.