Abstract: According to the hypothesis of internal mammary sentinel lymph node (IM-SLN) lymphatic drainage pattern, a modified radiotracer injection technique (periareolar intraparenchyma, high volume, and ultrasonographic guidance) was established.

To verify the accuracy of the hypothesis and validate the modified radiotracer injection technique and to observe whether the lymphatic drainage of the whole breast parenchyma could reach to the same IM-SLN, different tracers were injected into different locations of the breast.

The validation study results showed that the correlation and the agreement of the radiotracer and the fluorescence tracer are significant (case-base, rs =0.808, P,0.001; Kappa =0.79, P,0.001).

It proved that the lymphatic drainage from different location of the breast (the primary tumor, the subareolar plexus) reached the same IM-SLNs and the hypothesis of IM-SLN lymphatic drainage pattern (ie, IM-SLN receives lymphatic drainage from not only the primary tumor area, but also the entire breast parenchyma).

In other words, it validated the accuracy of our modified radiotracer injection technique.

Keywords: breast cancer, internal mammary, sentinel lymph node biopsy, visualization rate