Validation study for the hypothesis of internal mammary sentinel lymph node lymphatic drainage in breast cancer

// Bin-Bin Cong 1, 2 , Peng-Fei Qiu 2 , Yan-Bing Liu 2 , Tong Zhao 2 , Peng Chen 2 , Xiao-Shan Cao 1, 2 , Chun-Jian Wang 2 , Zhao-Peng Zhang 2 , Xiao Sun 2 , Jin-Ming Yu 3, * , Yong-Sheng Wang 2, * 1 School of Medicine and Life Sciences, University of Jinan and Shandong Academy of Medical Sciences, Jinan, Shandong, China 2 Breast Cancer Center, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, Shandong, China 3 Department of Radiotherapy, Shandong Cancer Hospital Affiliated to Shandong University, Jinan, Shandong, China * These authors have contributed equally to this work Correspondence to: Yong-Sheng Wang, email: wangysh2008@aliyun.com Jin-Ming Yu, email: sdyujinming@126.com Keywords: breast cancer, internal mammary, sentinel lymph node biopsy, visualization rate, indocyanine green Received: January 13, 2016      Accepted: May 09, 2016      Published: May 26, 2016 ABSTRACT According to axilla sentinel lymph node lymphatic drainage pattern, we hypothesized that internal mammary sentinel lymph node (IM-SLN) receives lymphatic drainage from not only the primary tumor area, but also the entire breast parenchyma. Based on the hypothesis a modified radiotracer injection technique was established and could increase the visualization rate of the IM-SLN significantly. To verify the hypothesis, two kinds of tracers were injected at different sites of breast. The radiotracer was injected with the modified technique, and the fluorescence tracer was injected in the peritumoral intra-parenchyma. The location of IM-SLN was identified by preoperative lymphoscintigraphy and intraoperative gamma probe. Then, internal mammary sentinel lymph node biopsy (IM-SLNB) was performed. The fluorescence status of IM-SLN was identified by the fluorescence imaging system. A total of 216 patients were enrolled from September 2013 to July 2015. The overall visualization rate of IM-SLN was 71.8% (155/216). The success rate of IM-SLNB was 97.3% (145/149). The radiotracer and the fluorescence tracer were identified in the same IM-SLN in 127 cases, the correlation and the agreement is significant ( Case-base, r s =0.836, P <0.001; Kappa =0.823, P <0.001). Different tracers injected into the different sites of the intra-parenchyma reached the same IM-SLN, which demonstrates the hypothesis that IM-SLN receives the lymphatic drainage from not only the primary tumor area but also the entire breast parenchyma.