Clinical and therapeutic importance of sentinel node biopsy of the internal mammary chain in patients with breast cancer: a single-center study with long-term follow-up.

BACKGROUND: We evaluated the incidence of sentinel lymph nodes (SLNs) in the internal mammary chain, calculated the lymphoscintigraphy and surgical detection rates, and evaluated the clinical effect on staging and the therapeutic approach in patients with breast cancer. METHODS: The study involved 741 women diagnosed with breast cancer eligible for the SLN technique. Lymphoscintigraphy was performed on the day before the operation by peritumoral injection of (99m)Tc-labeled nanocolloid. During the operation, a gamma probe was used to detect the SLN, which was then removed. RESULTS: A total of 719 SLNs were found in the axillary chain and 72 in the internal mammary chain. Preoperative lymphoscintigraphy showed 107 hot spots in the internal mammary chain, but only 72 SLNs in 65 patients were identified by the gamma probe and then removed with no complications. Of these 65 patients, 10 had a positive internal mammary chain SLN on final pathologic examination, whereas 55 patients had >or=1 negative SLNs on final pathologic analysis. Thirty-five (53%) of 65 patients had also an axillary SLN, but only 5 patients (8%) had a positive SLN on pathologic analysis. CONCLUSIONS: Evaluation of the SLNs in the internal mammary chain may provide more accurate staging in breast cancer patients. If an internal mammary sampling is not performed, patients may be understaged. This technique may allow better selection of those patients who will be submitted to adjuvant locoregional radiotherapy.