Clinical study on lymphatic drainage patterns of breast cancer

Objective To explore the features of lymphatic drainage patterns of breast cancer under physiologic conditions.Methods From Nov 2004 to May 2005,there were 206 consecutive patients enrolled in this study,191 of them received preoperative lymphoscintigraphy.Sentinel lymph node biopsy and endoscopic approach after liposuction were used to prove the lymphatic drainage pathways and sentinel lymph nodes.Results Internal mammary sentinel nodes were revealed in 74 patients(46.84%)who had received peritumoral and subdermal injections of radiolabeled tracer by lymphoscintigraphic scanning.The surveys by lymphoscintigraphy,sentinel node biopsy and endoscopic approach after liposuction proved that the lymph from breast parenchymal tissue or the skin and subdermal tissue flowed directly to the axillary basin or internal mammary nodal basin,the axillary sentinel nodes were situated in the same intersection of the second costal bone and the margin of major pectoral muscle,and the axillary sentinel nodes in some patients were composed of the superficial group and the profound group.The overall frequency of internal mammary node metastases in breast cancer was 26.6%.The frequency in patients with ≥4 positive axillary nodes was 50.7%.The metastatic internal mammary nodes appeared in the second intercostal space with a high frequency.There was no statistic relation between internal mammary nodes metastases and tumor location or tumor size.Conclusion Most lymph from the parenchymal tissue and the skin of the breast flows directly to the axillary and internal mammary nodal basins,and does not pass through the subareolar plexus.The deep and superficial collecting lymphatic vessels mostly run to the same axillary sentinel node in most patients,and may drain to the superficial and profound sentinel nodes.Internal mammary node biopsy is necessary for selected cases to provide information for accurate stage,treatment and prognosis of breast cancer.