Objectives: The sentinel node is defined as the node with the highest probability of being involved in the case of lymphatic spread from a tumor. Accurate identification and biopsy of this node can avoid unnecessary lymphadenectomies. The aim of this study was to determine if there are differences in the number of isolated sentinel lymph nodes in breast cancer according to whether a mixed technique (vital dye plus isotopic tracer) or radiotracer alone is used and if there are differences in the detection of more than one lymphatic basin and in the number of lymphatic nodes depending on the site of tracer injection.
Patients and method: A total of 173 sentinel lymph node biopsies in 173 women with breast cancer were studied taking into account the technique (mixed [n = 109] or radiotracer alone [n = 64]) and the location of tracer injection (periareolar [n = 81], intra and/or peritumoral [n = 92]). The number of lymphatic basins and the number of sentinel nodes were compared among the distinct groups resulting from the combination of the 2 parameters.
Results: Simultaneous drainage to both the axilla and internal mammary chain was more frequent with the intra-periareolar technique. The number of identified nodes was significantly higher when mixed techniques were compared, and was higher with periareolar injection than with the intra-peritumoral route.
Conclusions: In breast cancer sentinel lymph node biopsy, the number of identified nodes is not influenced by the use of a mixed technique or radiotracer alone. However, the number of identified nodes is higher with the periareolar route than with the intra-peritumoral route. Intra-peritumoral injection of the tracer shows a higher frequency of internal mammary chain drainage than periareolar injection, although this difference was not statistically significant.