Preoperative diagnosis of sentinel lymph node (SLN) metastasis using 3D CT lymphography (CTLG)

Sentinel lymph node biopsy (SLNB) became a standard procedure for patients with early breast cancer, however, an indication of SLN navigation to metastatic disease may lead to misdiagnosis for staging. Preoperative CTLG with a water-soluble iodinated contrast medium visualizes the correct primary SLNs and its afferent lymphatic channels surrounding detailed anatomy, therefore it can predict LN metastasis by visualizing the lymph vessel obstruction or stain defect of the SLN by tumor. The current study presents the value of CTLG for preoperative prediction for SLN status.

A total of 228 patients with Tis-T2 breast cancer who did not receive primary chemotherapy were studied. SLN metastasis was diagnosed according to the following staining patterns of SLNs and afferent lymphatic vessels: stain defect of SLN, obstruction, stagnation, dilation, and detour of the lymphatic vessels by tumor occupation. The diagnosis was compared with the pathological results to evaluate the accuracy of prediction for SLN metastasis using CTLG.

Twenty-seven of 228 patients had metastatic SLN pathologically. Twenty-five of these were diagnosed as metastatic preoperatively. The accuracy for metastatic diagnosis using CTLG was 89.0%, sensitivity was 92.6%, and specificity was 88.6%. The positive predictive value was 52.1% and negative predictive value was 98.8%.

CTLG can select the candidate with truly node negative cases in early breast cancer patients, because it predicts lymph node metastasis preoperatively from natural status of the lymphographic image. It also might omit the SLN biopsy itself.