The Findings of SPECT/CT Concerning Bypass Lymph Circulation in Lymphedema Following Breast Cancer Surgery.

This study aimed to determine whether bypass circulation was present in lymphedema and its effect. This was a retrospective, cross-sectional study. Patients who underwent unilateral breast cancer surgery with axillary lymph node dissection were recruited and underwent single-photon emission tomography/computed tomography (SPECT/CT). SPECT/CT was performed to detect the three-dimensional locations of radio-activated lymph nodes. Patients with radioactivity in anatomical locations other than axillary lymph nodes were classified into a positive group. All patients received complete decongestive therapy (CDT). Exclusion criteria were as follows: History of bilateral breast cancer surgery, cervical lymph node dissection history, and upper extremity amputation. The difference in the upper extremity circumference (cm) was measured at four points: Mid-point of the upper arm, elbow, and 10 and 15 cm below the elbow. Twenty-nine patients were included in this study. Fifteen patients (51.7%) had bypass lymphatic systems on the affected side, six (20.7%) had a bypass lymphatic system with axillary lymph nodes on the unaffected side, and 11 (37.9%) showed new lymphatic drainage. The positive group showed significantly less swelling than the negative group at the mid-arm, elbow, and 15 cm below the elbow. Bypass lymphatic circulation had two patterns: Infraclavicular lymph nodes and supraclavicular and/or cervical lymph nodes. Changes in lymph drainage caused by surgery triggered the activation of the superficial lymphatic drainage system to relieve lymphedema. Superficial lymphatic drainage has a connection through the deltopectoral groove.