Prognostic Nomogram for Prediction of Axillary Pathologic Complete Response After Neoadjuvant Chemotherapy in Cytologically Proven Node-Positive Breast Cancer

To develop a nomogram predicting probability of axillary pathologic complete response (pCR) in patients with cytologically proven axillary node-positive breast cancer who received neoadjuvant chemotherapy (NAC).The current management of axillary intervention in node-positive breast cancer patients who received NAC is axillary lymph node dissection (ALND) regardless of axillary pCR.We reviewed the records of 415 patients with cytologically proven node-positive breast cancer that were treated with NAC followed by surgery between 2008 and 2012 at Severance Hospital, Yonsei University Health System. Baseline patient and tumor characteristics, chemotherapy regimen, and tumor and nodal responses were analyzed. A nomogram was developed using a binary logistic regression model with a training cohort and validated in an independent cohort of 110 patients.Axillary pCR was achieved in 38.8% of the patients who underwent ALND after NAC. Axillary pCR was associated with initial clinical nodal status, negative estrogen receptor status, positive human epidermal growth factor receptor 2 (HER2) status with trastuzumab, and clinical nodal and tumor responses. A nomogram was developed based on the clinical and statistically significant predictors. It had good discrimination performance (AUC 0.82, 95% CI, 0.78-0.86) and calibration fit. The nomogram was independently validated, indicating the good predictive power of the model (AUC 0.80, 95% CI, 0.72-0.88).Our nomogram might help predict axillary pCR after NAC in patients with initially node-positive breast cancer. Patients with a high probability of achieving axillary pCR could be spared ALND, avoiding postoperative morbidity.