Evaluation of Extra-axillary Lymph Nodes by Ultrasound in Breast Cancer Patients

Abstract

An integral part of management of breast cancer is the appropriate treatment of the involved lymph nodes. While axillary nodes are always assessed and managed by sentinel node biopsy or an axillary clearance, the extra-axillary nodes do not receive equivalent attention even though they may influence staging, treatment, and prognosis. The purpose of this study was to assess the extra-axillary nodes by Doppler ultrasonogram in 228 patients with breast cancer over an 8-year period from January 2012 to January 2020. It is a case series analysis to evaluate axillary and extra-axillary lymph node basins in newly diagnosed breast cancer patients using linear array transducer ultrasonogram. It was found that while patients with T1 and T2 lesions did not have extra-axillary nodal involvement, 12% of T3 lesions (102 patients) and 50% of T4 lesions (48 patients) exhibited extra-axillary node involvement. Among the extra-axillary sites, internal mammary nodes were most often involved (24 patients) followed by infra-clavicular (8 patients) and supra-clavicular (4 patients) sites. Clinical examination by palpation could detect only the supra-clavicular nodes but was false negative in all patients who had an internal mammary or infra-clavicular node detected on ultrasound. Failure to identify internal mammary, supra-clavicular, and infra-clavicular lymph nodes can result in erroneous understaging in breast cancer patients leading to inadequate treatment and worse than anticipated prognosis. Therefore, all breast cancer patients as part of their pre-treatment protocol should undergo focused ultrasonogram evaluation of their axillary as well as extra-axillary lymph nodes.