Sentinel lymph node biopsy
A breast tumor may spread around the body via blood and lymphatic vessels. One of the characteristic areas for metastases are regional, i.e., axillary lymph nodes. Information about the presence or absence of metastases in them is very important to prescribe the right treatment. To obtain reliable information the samples of the respective lymph nodes are collected to perform their histological examination. It is known that if there are no clinical and radiological signs of involvement, meaning if the lymph nodes are not enlarged on palpation and show no changes on ultrasound or radiological examination (mammography, MRI, CT, PET-CT), the probability that they are affected with ‘invisible’ metastases does not exceed 25-30%. At the same time removing healthy lymph nodes that are not affected by the disease only leads to increased likelihood of such serious complications as chronic lymphostasis. You can learn about the presence of absence of metastases without removing all lymph nodes, but by only examining the sentinel lymph nodes. They are called ‘sentinel’ because they are the first on the path of lymphatic drainage from the tumor and thus are the first to receive metastases if they appear. As a rule, there are from 2 to 5 of them out of the total number of lymph nodes (25-30) located in the axillary region. So, if the metastases are not found in the sentinel lymph node, the probability of their spread to other lymph nodes is extremely small. Therefore, the examination of just the sentinel lymph nodes allows to obtain reliable information while minimizing the injury and avoiding serious complications.
Different substances are used to identify the sentinel lymph nodes – the lymphotropic dyes (i.e., the colored compounds that are distributed by the lymphatic system and accumulate in the sentinel lymph nodes, showing them) or lymphotropic proteins which contain a radioactive isotope. The isotope’s activity is defined with a portable radiation detector.
At our hospital we use Indocyanine Green – a lymphotropic substance that starts to ‘glow’ when exposed to infrared rays. A special camera with a monitor is used for this purpose. This procedure is safe and reliable. It allows to significantly reduce the trauma caused by the treatment as well as avoid multiple complications.