Nomogram for accurate prediction of breast and axillary pathologic response after neoadjuvant chemotherapy in node positive patients with breast cancer

Purpose: Many patients with cytology proven node-positive breast cancer receive a neoadjuvant chemotherapy (NAC) treatment. We developed a nomogram to predict the breast and axillary pathologic complete responses (pCR) in patients with a cytologically proven axillary node positive breast cancer with NAC. Methods: We selected 995 patients who were diagnosed with an invasive breast cancer and axillary lymph nodes metastasis, and who were treated with NAC followed by a curative surgery at the Samsung Medical Center between January 2007 and December 2014. The baseline patient and tumor characteristics, chemotherapy regimen, and tumor and nodal responses were thoroughly analyzed and reviewed. A nomogram was developed using a binary logistic regression model with a cross validation. Results: Axillary pCR was achieved in 47.3% and breast pCR was achieved in 24.3% of the patients after NAC. In this case, the both pCR was associated with an initial clinical tumor stage, negative progesterone receptor status, positive human epidermal growth factor receptor 2 status, and clinical radiologic nodal responses. A nomogram was developed based on the clinical and statistically significant predictors. It had good discrimination performance (area under the curve [AUC], 0.868; 95% confidence interval, 0.84-0.89) and calibration fit as noted in that case. The cross validation had an average AUC 0.853 (0.837-0.869). Conclusion: Our nomogram might help to predict breast and axillary pCRs after NAC in patients with an initially node-positive breast cancer. Minimal surgery might be acceptable in patients for whom the nomogram indicates a high probability of achieving pCRs.