Five axillary node groups beyond sentinel node observed by 3D-CT lymphography, evaluated for avoiding axillary dissection with sentinel node metastasis

Abstract

595 Background: The detailed relations between lymph nodes and lymph flow can be clarified using 3D-CT lymphangiography (LG). Systematic collection of lymph nodes based on 3D-CT LG decreases unnecessary lymph node dissection, even if the sentinel nodes (SNs) has metastasized, and can decrease complications. Moreover, endoscopy lowers infestation. We reviewed a validity of 3D-CT LG and a metastatic pattern of axillary nodes and SNs of 40 metastasis-positive cases among 186 sentinel node biopsies. 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 Iopamiron 300 was injected subcutaneously. A 16-channel multidetector-row helical CT scan 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. SN biopsy was performed by dye-staining method using endoscopy. The SNs were found by following the dye in the lymph ducts on video monitor. SNs and the second and the third nodes were sampled by same way. Results: We performed SN biopsy with 3D-CT LG in 146 patients. We can recognize the passage of lymph flow from SN into the venous angle and can classify these nodes into five groups. Detection rate was 100% for SN; 80.1% for the third group; and 30.1% for the fifth group. Multiple nodes were observed in SN (19.9%), in the second group (10.1%) and in the third group (4.3%). SN metastasis was positive in 40 patients, and only SN metastasis was found in 21 patients (52.5%) among them; SN and second group metastases were in 19 patients; SN and second and third group metastases were in 16; beyond the third group metastasis was in 11. But any skip metastasis beyond second and third nodes was not observed. Conclusions: By 3D-CT LG, we can recognize the accurate and more precise lymph flow. 52.5% of SN metastasis-positive patients had no metastasis in other nodes. They can be candidates for preserving their axillary node. 3D-CT LG guided SN biopsy for the second and third groups will predict their existence and help us to avoid dissecting needless nodes. No significant financial relationships to disclose.