The Epitrochlear and Humeral Lymphatic Pathway: Deep Lymphatic System Compensation After Axillary Lymph Node Dissection.

BACKGROUND AND OBJECTIVES: Superficial-to-deep lymphatic drainage has been proposed as a mechanism to reduce an individual's risk of developing breast cancer-related lymphedema (BCRL). The epitrochlear-humeral pathway provides superficial-to-deep lymphatic drainage and may be preferentially recruited when the superficial lymphatic system becomes inadequate. We evaluated the presence or absence of epitrochlear-humeral lymph node drainage in breast cancer survivors post-axillary lymph node dissection (ALND) who did not develop BCRL. METHODS: Female breast cancer survivors without BCRL after ALND underwent lymphatic mapping with ICG lymphography and SPECT/CT lymphoscintigraphy. The presence of epitrochlear and/or humeral drainage was recorded and compared between volunteers based on linear versus nonlinear patterns on ICG lymphography. RESULTS: Twenty-five volunteers, a median of 13.0 years after ALND, met the inclusion criteria. Drainage to both the epitrochlear and humeral nodes was observed in 56% (14/25). Linear ICG patterns were present in 32% (8/25), while 68% (17/25) demonstrated nonlinear patterns. Epitrochlear and humeral drainage was observed in 38% (3/8) of volunteers with linear patterns compared with 65% (11/17) of those with nonlinear patterns. CONCLUSIONS: Superficial-to-deep lymphatic drainage is common in breast cancer survivors without BCRL after ALND and may represent an important compensatory mechanism of the deep lymphatic system.