A sentinel lymph node is the lymph node in which tumor cells from a primary tumor are more likely to spread.
Sometimes there is more than one sentinel lymph node.
What are lymph nodes?
Lymph nodes are small roundish organs that are part of the lymphatic system.
There are many of them throughout the body and they are connected by lymphatic vessels.
There are groups of lymph nodes in:
A clear fluid called lymph flows through the lymphatic vessels and lymph nodes.
The lymph that flows in the lymphatic vessels arises from a fluid (interstitial fluid) that emerges from the small blood vessels called capillaries.
This liquid contains many substances, including:
- Blood plasma
- Mineral salts
The interstitial fluid also absorbs the waste products from the cells and other materials such as bacteria and viruses to eliminate them.
The lymphatic vessels of the body begin in the tissues and reach two large collection ducts (lymph collection strains) at the base of the neck. The lymphatic system goes only in the direction of the heart, it is a circulation parallel to the venous circle.
The lymph enters the blood via these collection strains.
Lymph nodes are important parts of the body’s immune system. They contain:
- other cell types of the immune system.
These cells control the presence of foreign microorganisms in the lymph, such as bacteria and viruses.
If a foreign agent is present, some cells are activated and trigger an immune response.
Lymph nodes are called reactive when the lymphocytes that are inside react against microorganisms that cause infection. Biopsy
Die Untersuchung der Lymphknoten ist auch wichtig um festzustellen, ob Tumorzellen die Eigenschaft entwickelt haben, sich in andere Körperbereiche zu verteilen (Metastasen).
Man darf den Befall durch Tumorzellen nicht mit vergrößerten Lymphknoten (Schwellungen) verwechseln.
Viele Krebsarten verbreiten sich über das Lymphsystem und die ersten Gebiete, in die sie gelangen, sind die naheliegenden Lymphknoten.
Aus diesem Grund gehören die Wächterlymphknoten zu den wichtigsten Prognosefaktoren.
Biopsy of the sentinel lymph node
Sentinel lymph node biopsy (SNLB) is a procedure in which the sentinel lymph node:
- is examined to determine whether tumour cells are present.
A histological examination is carried out in a laboratory, in which the cells are analyzed microscopically.
This examination can help the doctor:
- define the stage of the tumour (spread of the disease in the body),
- to develop an appropriate therapy.
Why is a biopsy of the sentinel lymph node performed?
Biopsy of the sentinel lymph node is performed to determine whether the tumor cells have migrated to the lymphatic system.
The sentinel lymph node biopsy is regularly applied to people with:
- breast tumor,
Sometimes the biopsy of the sentinel lymph node is also performed in other cancers, such as:
- Cervical cancer
- Colon tumor
- Endometrial tumor
- Tumor on the head and neck
- Gastric tumor
- Thyroid tumor
- Bladder tumor
- Vulvar tumor
Where is the sentinel lymph node? Localization
After taking a tissue sample, it is necessary to locate the sentinel lymph node.
There are two methods of localizing the sentinel lymph node:
- Radioactive solution – A low-level radioactive solution is injected near the tumor.
This solution enters the lymphatic system and leads to the sentinel lymph node.
The injection is usually given a few hours or days before the surgical procedure to remove the sentinel lymph node.
- Vital dye (methylene blue) – The doctor may inject a harmless dye near the tumor. This substance quickly enters the lymphatic system and gets to the sentinel lymph node, which turns bright blue. Usually, the blue dye is injected shortly before the surgical removal of the sentinel lymph node.
Whether the radioactive solution or the blue dye is used to locate the sentinel lymph node usually depends on the surgeon’s preference.
- Scintigraphy – Lymph scintigraphy is a diagnostic examination performed in the nuclear medicine department.
This procedure is used to identify and “photograph” the sentinel lymph node using a device called a “gamma camera” after injection of a radiopharmaceutical agent (weakly radioactive dye).
The procedure for marking and biopsy of the sentinel lymph node implies radiation exposure, even if it is low.
For this reason, the doctor conducting the examination must have a special license.
Procedure and technique for the biopsy of a sentinel lymph node
- As a rule, the surgeon performs the biopsy of the sentinel lymph node under general anesthesia, so you are not aware during the operation and do not feel any pain.
- The surgeon begins with a small incision above the lymph node.
- If the radioactive solution was injected before the procedure, the surgeon uses a special technique and a small, portable instrument called a gamma detector to determine the location where the greatest accumulation of radioactivity exists and identify the sentinel lymph nodes.
- If the doctor has used methylene blue as a dye, the sentinel lymph nodes turn blue and become visible.
- In most cases, the surgeon removes each of the 2 or 3 existing sentinel lymph nodes and sends them to the pathologist for microscopic examination of the carcinogenic tissue.
- In some cases, biopsy of sentinel lymph nodes and surgical removal of possible cancerous tissue can be performed simultaneously.
In other cases, the biopsy of the sentinel lymph nodes is performed first and later the surgical removal of the tumor.
- However, the immediate examination of the lymph node can show a false negative result. Then it is necessary to perform surgical removal after histological examination.
After biopsy of a sentinel lymph node
- After the biopsy of a sentinel lymph node, the patient is placed in a hospital room, where the medical staff checks whether postoperative complications occur.
- If the patient does not undergo any further surgery, he is discharged home the same day.
- The recovery time until he returns to normal activity depends on the situation.
- As a rule, there are no long-term consequences, because many other lymph nodes remain in the vicinity.
- If the biopsy of the sentinel lymph node is performed during surgery to remove a cancerous tumor, the length of hospitalization depends on the severity of the operation.
After a biopsy procedure of the sentinel lymph node
After the procedure, the wound usually causes:
- Chest, shoulder and arm pain
- Tingling or numbness:
These symptoms can also last for several months.
Return to everyday activities:
As a rule, the bandage is removed 7 days after the procedure and you can take a shower. Wash the wound with neutral soap.
After the procedure, you should wait 3-4 weeks until you drive again. The movements in the car can:
- cause pain,
- Limit driving ability.
Depilation and deodorants
For 4 weeks you should refrain from:
- use of deodorants on the wound,
Exercises after biopsy of the sentinel lymph node in breast tumor
Removal of the sentinel lymph node can cause problems with arm movement.
Adhesions can form that restrict movement.
Important for regaining mobility after the procedure is:
- arm movement, as soon as the pain allows it,
- special exercises,
- manual scar solution (manipulation or massage) so that no adhesions form.
Research results on the biopsy of the sentinel lymph node in breast cancer
- The cells of breast cancer first enter the lymph nodes, which are located in the armpit or armpit region near the affected breast.
- In breast tumors near the sternum, however, the tumor cells can first spread to the lymph nodes in the rib cage (under the sternum) before they are detected in the armpit.
- As a rule, the number of lymph nodes in the armpit is between 20 and 40, but this varies from person to person.
In the past, the therapy of breast tumors involved the removal of these lymph nodes (in an operation called axillary lymph node dissection) for two reasons:
- to enable the classification of breast cancer,
- to prevent recurrence of the disease.
- A regional recurrence of breast cancer occurs when the tumor cells that have migrated to the nearby lymph nodes become the origin of a new tumor.
- Removing multiple lymph nodes at the same time can have adverse effects.
- There are scientific studies on the possibility of determining the stage of the tumor solely on the basis of the biopsy of a sentinel lymph node.
Of course, this is only possible if clinically there are no signs of metastases in the axillary lymph nodes, such as coarse and immovable lymph nodes.
- A biopsy can also be performed after chemotherapy.
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