Abstract Abstract #1012 Background: In early breast cancer, the presence of metastasis in axillary lymph nodes is an important factor in prognosis and further treatment. However, axillary node dissection causes many complications such as contracture of the shoulder joint, lymph edema, and paralysis of the upper extremities. Sentinel node (SN) biopsy provides us an information about no need to dissect axillary nodes for node-negative patients. But on node-positive patients, the conventional axillary node dissection has been performed. 3D-CT lymphography (LG) can show the precise individual lymphatic flow not only from the tumor to SN but also from SN to venous angle, which means breast lymphatic channel. We applied 3D-CT LG to distinguish them from the arm channel to avoid any arm complications.
 Materials and Methods: 3D-CT LG was performed on the day before the surgery to mark SN on the skin. Above the tumor and near the areola, 2 ml of Iopamidol was injected subcutaneously. A 16-channel multidetector-row helical CT images were taken at 1 min after injection for SN detection, and at 3 and 5 min for observing advancement of lymph flow into venous angle. They were reconstructed to produce a 3D image of lymph ducts and lymph nodes by shaded volume rendering method. SN biopsy and axillary node sampling were performed by dye-stain method using endoscopy.
 Results: We performed SN biopsy with 3D-CT LG in 146 patients. 3D-CT LG showed periareolar circular lymph ducts and complicated radial breast subcutaneous lymph ducts flow. They were connected to make a network. It clearly showed the precise lymphatic flow from the tumor to SN. 3D-CT lymphography can show sentinel lymph node at only one minute after injection. But following up to 3 minutes and 5 minutes after injection, we can follow the lymph ducts beyond SN into the second and the third nodes toward the venous angle with complex plexus. It shows five beads-like grouped nodes beyond SN. Detection rate was 100% for SN; 80.1% for the third group; and 30.1% for the fifth group. The position of SN and the other groups of axillary nodes were identified by their surrounding anatomical architecture of pectoral muscles and vascular systems, such as axillary vein, lateral thoracic artery, and thoracodorsal artery. Under the endoscopic technique, we can observe the dye-stained nodes in 63.3% of the second group and in 47.9% of the third group detected by 3D-CT LG. SN metastasis was positive in 40 patients, and only SN metastasis was found in 21 patients (52.5%) among them. Any skip metastasis beyond second and third nodes was not observed. Under the direct view, we can distinguish and the axillary node drained from the breast, guided by 3D-CT LG and dye-stain, in 40 patients with SN metastasis, and sample them selectively.
 Conclusions: By 3D-CT LG, we can recognize the accurate and more precise lymph flow, and their positional relations to surrounding anatomical architecture. It helps us easily to pursuit lymph flow and to remove SN and the axillary nodes from the breast selectively. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1012.
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