Bringing to Light the Invisible Lymphatic Anatomy of the Upper Extremity

Objective: To identify vulnerable upper extremity regions in native lymphatic anatomy that predispose women to the development of breast cancer-related lymphedema. Additionally, to identify currently available imaging technologies that could be repurposed for in-vivo lymphatic imaging of these anatomic regions and pathways. Background: Breast cancer-related lymphedema remains an incurable complication of breast cancer treatment, but improvements to knowledge of upper extremity lymphatic anatomy and imaging can unlock new techniques for prevention and treatment. Methods: “Bringing to Light the Invisible Lymphatic Anatomy of the Human Body” was a two day accelerator workshop held in May 2024 at the Harvard Radcliffe Institute attended by sixteen experts in lymphatic anatomy and imaging including four lymphatic anatomists, five imaging clinicians, three lymphatic scientists, and three program officers from the National Heart, Lung and Blood Institute (NHLBI) and Advanced Research Projects Agency for Health (ARPA-H). Results: Collateral pathways of the superficial lymphatic system, perforating lymphatic vessels, and the deep lymphatic system were implicated in preventing or reducing the severity of BCRL. Several strategies were proposed for repurposing existing imaging technology and developing new imaging technology that can improve understanding of the anatomy, function, and connectivity of lymphatic vessels in these three regions of the arm. Conclusion: Advancements in lymphatic imaging are central to refining our knowledge of lymphatic anatomy. Key challenges to lymphatic imaging are visualization of the deep lymphatic system and perforating lymphatic vessels.