Sentinel node

"Sentinel lymph node biopsy is a new advance in the treatment of some tumors. It allows us to perform less aggressive surgeries for the patient".


The analysis of the sentinel node informs about the degree of extension of the disease, in the most selective way possible, in order to determine the most effective and appropriate treatment, so that it can be individualized in each case.

When the cancer progresses it tends to spread through the blood and lymphatic vessels. The sentinel node is the first lymph node that tumor cells find when they try to spread through the lymph.

Once removed, the node is examined by an anatomopathologist, who will check whether it is affected by tumor cells or not. If it is positive, the disease could have spread to other areas of the patient's body.

The oncologist must then evaluate this information and, as a consequence, prescribe the most appropriate treatment.

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When is the sentinel lymph node indicated?

In the case of breast cancer, the main advantage is to avoid the complete removal of the lymph nodes in the armpit and therefore avoid complications in that arm such as fluid retention and swelling (lymphedema), lack of sensitivity in the skin of the forearm or decreased mobility of the arm.

This makes breast surgery less aggressive for the patient, the treatment plan indicated is as appropriate as possible and all this leads to a better recovery and a very good quality of life afterwards.

In melanoma, the lymph node is the first place affected in metastasis or extension of the disease to other organs. Therefore, it is indicated within the surgical treatment to perform the removal of the sentinel lymph node. It is a key factor in the cure.

Most frequent indications of this test:

  • Cancer of the cervix.
  • Breast cancer.
  • Cancer of the vulva.
  • Melanoma.

Do you have any of these diseases?

A sentinel node analysis may be necessary

How is sentinel node biopsy performed?

The injection of the radiopharmaceutical must be done half an hour before the lymphogram. The next day, during the operation, a coloring substance (methylene blue or others) will be injected into the tumor, which will migrate to the first lymph node or sentinel node in the area closest to the tumor mass.

The substance stains the node or sentinel nodes with blue so that they are visually marked, making it easier for the surgeon to locate them. By using a probe connected to a gamma radiation detector intraoperatively, the specialist locates the sentinel node where the radiopharmaceutical injected the day before remains. The probe emits a beep that becomes more intense the higher the concentration of the radioactive isotope it detects.

In this way, the surgeon can determine the exact location of the sentinel node and remove it for later analysis. Once the node has been removed, it is examined by an anatomopathologist, who will check whether or not it is affected by tumor cells.

Where do we do it?


The Nuclear Medicine Service
of the Clínica Universidad de Navarra

The Nuclear Medicine Service-PET is accredited by the European Association of Nuclear Medicine, an association that guarantees the excellence and quality control of the procedures performed in this service. This accreditation also facilitates access to phase I and II clinical trials.

We have the most advanced diagnostic technology, such as PET-CT, which allows us to detect small tumor lesions that were previously practically impossible to identify.

The Clinic is the only Spanish center with the capacity to synthesize and apply up to 18 types of radiopharmaceuticals.

Diagnostic tests we perform

  • Bone densitometry.
  • Gammagraphy.
  • Cellular markings.
  • Perfusion monitoring with TNF.
  • PET and PET-CT.
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Why at the Clinica?

  • We have the most advanced technology nationwide.
  • Radiopharmacy Unit with experts and capacity to synthesize the largest number of radiopharmaceuticals in Spain.
  • Radiophysics and Radiological Protection Unit to guarantee the safety of our patients and professionals.

Our team of professionals