Biopsies of the Internal Mammary Sentinel Lymph Nodes in Breast Cancer

The introduction of the sentinel lymph node (SLN) concept and its biopsy have deeply changed the management of many cancers [1,2]. The SLN is defined as the first LN to which cancer cell are most likely to spread from a primary tumour; in cT1-T2 breast cancer patients, the axillary (Ax) SLN biopsy is now considered the standard of care for staging clinically node-negative patients [3]. The AxLNs are the main LN basin of the breast, hence the main determinant of the patient’s LN status. However, the second lymphatic drainage basin of the tumour-bearing breast is represented by the internal mammary lymph nodes (IM LNs) and is often overlooked (if not ignored). Evaluation (imaging or operative) is not done routinely during the staging process in most breasts because the clinical importance of metastases in the IM LNs and their selective lymphadenectomy has been debated since the introduction of this technique. The aim of the present paper was to report the results from IMSLN biopsies and to review and discuss their impact on treatment and prognosis.