Sentinel node biopsy and internal mammary lymphatic mapping in breast cancer

Background: Currently outer quadrant breast tumors are not felt to have significant drainage to the internal mammary nodal chain. We evaluated the incidence of internal mammary sentinel nodes (IMSN) found with lymphoscintigraphy for all breast quadrants. Methods: Eighty women were prospectively studied by technitium-sulfur colloid injection, nuclear medicine imaging, and intraoperative gamma probe identification of sentinel nodes. IMSN detected were surgically removed. Results: Ten of 80 ( 12%) patients had IMSN identified in addition to axillary sentinel nodes (AXSN). Four tumors were located medially, 6 (60%) were in the outer quadrants. Metastatic disease was present in 3 of 10 women. Patients with positive IMSN also had positive AXSN. Conclusions: Patients undergoing lymphatic mapping for the management of breast cancer should have radiolabelled tracer and gamma probe sentinel node identification regardless of tumor location in the breast.