Longitudinal monitoring of the head and neck lymphatics in response to surgery and radiation

Background. The lymphatic vasculature provides a route for cancer metastases, and its dysfunction after cancer treatment can result in lymphedema. However, changes in the lymphatics before, during, and after surgery and radiation remain unclear. Methods. Near-infrared fluorescence lymphatic imaging was performed before and after lymph node dissection and fractionated radiotherapy to assess changes in external lymphatic function. Results. Patients who underwent both lymph node dissection and radiotherapy developed lymphatic dermal backflow on treated sides ranging from days after the start of radiotherapy to weeks after its completion, whereas contralateral regions that were not associated with lymph node dissection but also treated with radiotherapy experienced no such changes in external lymphatic anatomies. Conclusion. The external lymphatics undergo transient changes during and weeks after lymph node dissection and radiotherapy. (C) 2017 Wiley Periodicals, Inc.