Indocyanine Green Fluorescence-Guided Axillary Reverse Mapping for Axillary Lymph Node Dissection in Breast Cancer: The FARM Trial.

BACKGROUND

Lymphedema is a significant complication following axillary lymph node dissection (ALND). Axillary reverse mapping (ARM) is a technique aimed at identifying and preserving lymphatic drainage of the upper limb during ALND to prevent lymphedema. However, concerns regarding tracer reliability and oncological safety have hindered its widespread use. This study assessed feasibility of indocyanine green fluorescence-guided ARM during ALND and explored predictive factors for ARM node metastasis.

METHODS

In this prospective trial (ACTRN12621000817842), patients with clinically node-positive breast cancer or positive sentinel lymph node biopsy requiring ALND (2022-2025) were enrolled. Indocyanine green was injected into the upper arm to visualize lymphatics using near-infrared fluorescence during ALND. Axillary reverse mapping nodes were categorized by anatomical zone based on intersection of lateral thoracic vein (vertical) and second intercostobrachial nerve (horizontal). Axillary reverse mapping nodes were sent separately for histopathological analysis. Univariate and multivariate analyses were performed on patient, tumor, and nodal characteristics.

RESULTS

Among 100 patients, ARM nodes were identified in 95% (95% confidence interval [CI] 88.7-98.4), yielding 111 nodes. Of these, 68.5% were located in the upper lateral axilla. Metastatic involvement of ARM nodes occurred in 18.9% of cases. Multivariate analysis identified tumor size ≥ 50 mm (hazard ratio [HR] 1.98, 95% confidence interval [CI] 0.25-3.83, p = 0.04) and higher nodal stage (N2/N3) (HR 3.04, 95% CI 1.37-4.58, p = 0.015) as independent predictors of ARM node metastasis.

CONCLUSIONS

Indocyanine green fluorescence-guided ARM is a feasible technique during ALND. However, the risk of ARM node metastasis in advanced disease suggests that routine ARM node preservation may be unsafe, indicating the need for alternative strategies, such as lymphaticovenous anastomosis, to mitigate lymphedema risk.