Development of a predictive score of axillary lymph node dissection based on targeted axillary dissection in patients with breast cancer diagnosis, affected lymph nodes, and neoadjuvant treatment

To determine predictive factors of axillary lymph node dissection (ALND) results in breast cancer (BC) patients undergoing neoadjuvant chemotherapy (NACT), and subsequent staging using Targeted Axillary Dissection (TAD). Case-control study between January 2016 and August 2019. Patients with BC, cN1 staging, marked with a metallic clip prior to NACT, and subsequently staged with TAD and ALND were included. They were divided into 2 groups: ALND patients with or without metastatic involvement (group 1 and group 2, respectively). We carried out a univariate analysis comparing clinical, radiological, surgical and pathological variables, and a logistic regression, (dependent variable: positive result of ALND; independent variables: number of suspicious lymph nodes in diagnostic ultrasound, positive hormone receptors, HER2 positive, complete clinical-radiological response to NACT, positive TAD, and biopsy of ≤2 nodes in TAD). A score for prediction of a metastatic ALND was proposed, with an internal validation study. 60 patients were included: Group 1: 33 (55.0%); Group 2: 27 (45.0%). Tumor size (Odds Ratio (OR) = 1.67; 95%CI 1.02–2.74), number of suspected nodes in ultrasound (OR = 2.20; 95%CI 1.01–4, 77), HER2 positive (OR 0.04; 95%CI 0.003–0.54), clinical-radiological response to NACT (OR = 0.07; 95%CI 0.01–0.75), and positive TAD (OR 15.48; 95%CI 1.68–142.78) were independent predictors of a positive result in ALND. We developed a “positive ALND predictive score”, with good calibration (Hosmer-Lemeshow test: p = 0.65), and discrimination (AUC = 0.93; 95% CI 0, 87–0.99), with highest Youden index (0.7) at cut-off point of 17% risk of positive ALND (sensitivity = 100%; specificity = 70%). Tumor size, number of suspected nodes, positive HER2, response to NACT, and metastatic TAD are independent predictors of ALND. The predictive score for positive ALND would be a good indicator to safely omit ALND. •TAD is a new technique validated in last years as an axillary re-staging technique.•There may be other factors to predict ALND status: IHC, and clinical NACT response.•Tumor size, LN number, HER2, NACT response and TAD are predictive of ALND results.•A score including said factors has good internal value to predict the ALND results.