Is Sentinel Node Biopsy of the Internal Mammary Lymph Nodes Relevant in the Management of Breast Cancer?

The aim of this study was to review the outcomes of a series of breast cancer patients who underwent sentinel node biopsy inclusive of lymphoscintigraphy, and to assess the incidence of internal mammary node (IMN) metastatic positivity at exploration and whether these findings influenced treatment. Between April 2001 and December 2012, 581 breast cancer patients at Princess Alexandra Hospital underwent preoperative lymphoscintigraphy in the course of the performance of sentinel node biopsy. Analysis was performed of those patients who demonstrated radio-isotope uptake to the IMN chain, and who had sentinel node biopsy of the IMN's and were found to have metastatic involvement. Assessment was made to determine whether the finding of IMN metastases changed the adjuvant systemic management of these patients, and to review complication rates. 95 of 581 (16.4%) patients with preoperative breast lymphoscintigraphy had lymphatic mapping to the IMN chain. 51 (54%) of these patients had IMN chain surgically explored and IMN nodes were found in 35 of these patients (success rate of 69%). Of these, three patients (3/35 = 8.6%) had metastatic involvement of the IMN sentinel node group. All three IMN positive patients received adjuvant breast radiotherapy, chemotherapy, and hormonal therapy. In four patients (7.8%) IMN surgical exploration was complicated by pneumothorax. Only a small proportion of breast cancer patients were found to have metastasic involvement of the IMN chain and which did not significantly change their adjuvant therapy management. These findings suggest that the benefits of exploration of the IMN chain in breast cancer patients are limited and may be outweighed by the risk of complications.