Sentinel nodes identified by computed tomography-lymphography accurately stage the axilla in patients with breast cancer.

BACKGROUND: Sentinel node biopsy often results in the identification and removal of multiple nodes as sentinel nodes, although most of these nodes could be non-sentinel nodes. This study investigated whether computed tomography-lymphography (CT-LG) can distinguish sentinel nodes from non-sentinel nodes and whether sentinel nodes identified by CT-LG can accurately stage the axilla in patients with breast cancer. METHODS: This study included 184 patients with breast cancer and clinically negative nodes. Contrast agent was injected interstitially. The location of sentinel nodes was marked on the skin surface using a CT laser light navigator system. Lymph nodes located just under the marks were first removed as sentinel nodes. Then, all dyed nodes or all hot nodes were removed. RESULTS: The mean number of sentinel nodes identified by CT-LG was significantly lower than that of dyed and/or hot nodes removed (1.1 vs 1.8, p <0.0001). Twenty-three (12.5%) patients had ≥2 sentinel nodes identified by CT-LG removed, whereas 94 (51.1%) of patients had ≥2 dyed and/or hot nodes removed (p <0.0001). Pathological evaluation demonstrated that 47 (25.5%) of 184 patients had metastasis to at least one node. All 47 patients demonstrated metastases to at least one of the sentinel nodes identified by CT-LG. CONCLUSIONS: CT-LG can distinguish sentinel nodes from non-sentinel nodes, and sentinel nodes identified by CT-LG can accurately stage the axilla in patients with breast cancer. Successful identification of sentinel nodes using CT-LG may facilitate image-based diagnosis of metastasis, possibly leading to the omission of sentinel node biopsy.

Correlation between the area of high-signal intensity on SPIO-enhanced MR imaging and the pathologic size of sentinel node metastases in breast cancer patients with positive sentinel nodes.

BACKGROUND: We previously demonstrated that superparamagnetic iron oxide (SPIO)-enhanced MR imaging is promising for the detection of metastases in sentinel nodes localized by CT-lymphography in patients with breast cancer. The purpose of this study was to determine the predictive criteria of the size of nodal metastases with SPIO-enhanced MR imaging in breast cancer, with histopathologic findings as reference standard. METHODS: This study included 150 patients with breast cancer. The patterns of SPIO uptake for positive sentinel nodes were classified into three; uniform high-signal intensity, partial high-signal intensity involving ≥50% of the node, and partial high-signal intensity involving <50% of the node. Imaging results were correlated with histopathologic findings. RESULTS: Thirty-three pathologically positive sentinel nodes from 30 patients were evaluated. High-signal intensity patterns that were uniform or involved ≥50% of the node were observed in 23 nodes that contained macro-metastases and no node that contained micro-metastases, while high-signal intensity patterns involving <50% of the node were observed in 2 nodes that contained macro-metastases and 8 nodes that contained micro-metastases. When the area of high-signal intensity was compared with the pathological size of the metastases, a pathologic >2 mm sentinel node metastases correlated with the area of high-signal intensity, however, a pathologic ≤2 mm sentinel node metastases did not. CONCLUSIONS: High-signal intensity patterns that are uniform or involve ≥50% of the node are features of nodes with macro-metastases. The area of high-signal intensity correlated with the pathological size of metastases for nodes with metastases >2 mm in this series.

SPIO-enhanced magnetic resonance imaging for the detection of metastases in sentinel nodes localized by computed tomography lymphography in patients with breast cancer.

BACKGROUND: Superparamagnetic nanoparticle-enhanced magnetic resonance (MR) imaging has been reported to be a promising improvement for diagnostic imaging of lymph node metastases from various tumors. Moreover, sentinel nodes have been reported to be well identified using computed tomography (CT) lymphography (CT-LG) in patients with breast cancer. The aim of this study was to evaluate MR imaging with superparamagnetic iron oxide (SPIO) enhancement for the detection of metastases in sentinel nodes localized by CT-LG in patients with breast cancer. METHODS: This study included 102 patients with breast cancer and clinically negative nodes. Sentinel nodes were identified by CT-LG, and SPIO-enhanced MR imaging of the axilla was performed to detect metastases in the sentinel nodes. A node was considered nonmetastatic if it showed a homogenous low signal intensity and metastatic if the entire node or a focal area did not show low signal intensity on MR imaging. Sentinel node biopsy was performed, and imaging results were correlated with histopathologic findings. RESULTS: The mean number of sentinel nodes identified by CT-LG was 1.1 (range, 1-3). The sensitivity, specificity, and accuracy of MR imaging for the diagnosis of sentinel node metastases were 84.0%, 90.9%, and 89.2%, respectively. In 4 of 10 patients with micrometastases, metastases were not detected, but all 15 patients with macrometastases were successfully identified. CONCLUSIONS: SPIO-enhanced MR imaging is a useful method of detecting metastases in sentinel nodes localized by CT-LG in patients with breast cancer and may avoid sentinel node biopsy when the sentinel node is diagnosed as disease-free.