Background: Sentinel node biopsy (SNB) using dye and/or radioisotope often results in the identification and removal of multiple nodes as sentinel nodes (SN), although most of these nodes may be non-SN. CT-lymphography (CT-LG) can distinguish true SN from non-SN because of the visualization of the lymphatic channel. This study investigated whether true SN identified by CT-LG accurately stage the axilla in patients with breast cancer, making it sufficient to remove true SN alone.

Methods: This study included 168 patients with breast cancer with clinically negative nodes. Contrast agent was injected intradermally into the skin overlying the breast tumor and in the subareolar region. True SN were identified by CT-LG. Marking the location of true SN was performed on the skin surface using a CT laser light navigator system. SNB was performed using a combination of dye and radioisotope. Lymph nodes located just under the marking were first removed as true SN. Then, all dyed nodes or all hot nodes were removed.

Results: The mean number of true SN identified by CT-LG was 1.1 (range 1-3). The mean number of hot and/or dyed nodes removed was 1.8 (range 1-6). One hundred forty-seven patients (87.5%) had 1 true SN removed, 19 (11.3%) had 2 true SN removed, and 2 patients (1.2%) had 3 true SN removed. Twenty-one (12.5%) patients had ≥2 true SN removed, whereas 91 (54.2%) of patients had ≥2 hot and/or dyed nodes removed (P<0.0001). Pathologic evaluation demonstrated that 38 (22.6%) of 168 patients had metastasis to at least one node. All of these 38 patients demonstrated metastases to at least one of the true SN identified by CT-LG. There were no adverse events associated with CT-LG.

Conclusions: True SN identified by CT-LG accurately staged the axilla in patients with breast cancer. Removal of true SN alone may reduce the postoperative morbidity and cost of the procedure by decreasing the surgical duration as well as the cost of pathologic analysis.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-30.