Internal Mammary Nodes in Breast Cancer: A Review of the Literature and Practical Surgical Recommendations

Abstract

Background : Involvement of internal mammary lymph nodes with metastatic disease in breast cancer upstages the patient and carries a poorer prognosis. It is the most important prognostic factor after axillary nodal status. Although 75% of the breast lymphatic drainage goes to the axillary lymph nodes, extra-axillary lymph node basins drain the remainder. Extra-axillary recurrences led to the evolution from Halsted’s radical mastectomy to Wangensteen’s “super-radical” and Urban’s “extended-radical” mastectomies, which remove the internal mammary and supra-clavicular lymph nodes in addition to axillary nodes. However, these surgeries failed to improve disease free survival and overall survival and the interest in pursuing extra-nodal metastasis faded away. With the development of the sentinel node techniques, interest in extra-axillary lymph node metastasis was renewed because of identification of drainage to these locations. Several reports from different institutions demonstrate this renewed interest as well as the feasibility of procedures leading to upstaging and changing of treatment plans when metastasis to internal mammary nodes is identified. In this review, the literature addressing internal mammary lymph nodes in breast cancer is examined. Methods : Systematic review of the literature from 1867 to 2015. Conclusion : The techniques and factors that affect the reliability and reproducibility of internal mammary sentinel node biopsy are discussed. In addition, we discuss whether the treatment of positive internal mammary nodes translates into a survival advantage. Finally, we propose a minimally invasive working algorithm to internal mammary lymph node evaluation.