Development and validation of a nomogram for predicting axillary reverse mapping lymph node metastasis in breast...

Axillary reverse mapping (ARM) aims to preserve upper limb lymphatic drainage during breast cancer surgery to reduce lymphedema risk, but the metastatic potential of ARM lymph nodes and its preoperative predictors remain unclear.

A retrospective analysis was conducted on a development cohort of 142 breast cancer patients, with an independent temporal validation cohort of 54 consecutive patients. Indocyanine green and methylene blue were used to map upper limb and breast lymphatic drainage, respectively. Identified ARM lymph nodes were preserved and pathologically examined. Independent predictors of metastasis were identified via univariable and multivariable logistic regression. A preoperative nomogram was developed and validated.

ARM lymph nodes were successfully identified in 142 (92.81%) patients, with metastasis in 33 (23.24%). Four lymphatic drainage patterns were defined based on ARM-sentinel lymph node distance and shared trunks. Multivariate analysis identified several independent predictors: menarche age ≤ 12 years (P = 0.012), elevated fibrinogen (P = 0.008), elevated CA15-3 (P = 0.015), elevated platelet-to-lymphocyte ratio (P = 0.021), presence of sentinel ARM lymph nodes (P = 0.003), larger ARM lymph node long diameter (P < 0.001), and ultrasound-detected axillary abnormalities (P = 0.007). The nomogram demonstrated excellent discrimination in the development cohort (AUC = 0.934) and acceptable discrimination in the temporal validation cohort (AUC = 0.826).

ARM lymph node metastasis occurs in nearly one-quarter of patients. Our preoperative nomogram, incorporating menarche age, inflammatory and tumor markers, imaging, and ARM anatomy, can predict ARM lymph node metastasis risk, supporting selective ARM node preservation and reducing breast cancer-related lymphedema without compromising oncologic safety.