Surgical Approach to Internal Mammary Sentinel Node Biopsy

Background: Internal mammary node (IMN) metastasis has a similar prognostic importance as axillary nodal involvement. However, sampling of IMN is not performed routinely. Aims: To evaluate a simplified method for internal mammary sentinel node (IMSN) biopsy of breast cancer patients. Methods: A combination of simultaneous perilesional and intradermal radiocolloid injections over the lesion was used. All IMSNs were confirmed by lymphoscintigraphy and Carbon Nanoparticles Suspension Injection preoperatively and excised extrapleurally through the intercostal muscles. Results: Twenty-three of the 94 patients were found to have metastatic disease in the IMSNs. Four of 65 patients had metastases in the IMNs but not in the axilla. All 23 patients with positive IMSN were upstaged and received radiation to the internal mammary chain. The time from separating the pectoral major muscle to touch the node was ranged 21-48 min. The detecting sensitivity combined with preoperative lymphoscintigraphy, intraoperative gamma probe detection, and intraoperative black dye methods for IMSN was 100%. Conclusions: The approach used is a reliable surgical technique for removing IMSN. It can improve the nodal staging in breast cancer with IMN metastases.