Nomogram for predicting axillary lymph node status after neoadjuvant chemotherapy in breast cancer

Background: Many breast cancer patients benefit from neoadjuvant chemotherapy (NAC). However, sentinel lymph node biopsy (SLNB) after NAC remains controversial, especially for patients with axillary lymph node metastasis (ALNM) at diagnosis. We developed a nomogram for predicting axillary lymph node (ALN) status after NAC to screen for patients for whom SLNB may be beneficial. Methods: A total of 320 cT1-4N0-1M0 breast cancer patients receiving ALN dissection (ALND) after NAC were included. Univariate and multivariate logistic regression analyses determined significant factors for predicting ALN status. Efficacy of the resulting nomogram was assessed using receiver operating characteristic (ROC) and calibration curves, while decision curve analysis (DCA) was used to evaluated net clinical benefit. Our nomogram was validated using female patients grouped according to a diagnosis of node-positive (cN1) or node-negative (cN0) by ultrasound-guided needle biopsy of suspected lymph nodes before NAC. Results: Logistic regression analyses indicated that estrogen receptor (ER), Ki67, degree of tumor regression, clinical tumor T stage after NAC, and ALN Breast Imagining-Reporting and Data System (BI-RADS) category after NAC, were associated with ALN status. The resulting nomogram had an area under the curve (AUC) of 0.802 [95% confidence interval (CI), 0.7485-0.8554], and the calibration plot showed strong uniformity between predicted and actual ALN status. DCA indicated a positive net benefit of nomogram predictions in our cohort. After internal validation, the cN1 and cN0 groups had an AUC of 0.7926 (95% CI, 0.7187-0.8665) and 0.8165 (95% CI, 0.7381-0.8949), respectively. The calibration plot indicated better performance in the cN0 group. Conclusions: After NAC, some patients may benefit from SLNB. Our nomogram predicts ALN status after NAC and has great potential to assist in clinical decision-making.