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Sentinel node biopsy involves injecting a dye, called tracer material, which helps the surgeon locate the sentinel nodes.
Sentinel node biopsy is a surgical procedure performed to determine if cancer has spread from the site of the primary tumor to the lymphatic system. It is mostly used in evaluating breast cancer, thyroid cancer, melanoma, and several other cancers. The sentinel nodes are the first few lymph nodes to which the cancer spreads. Sentinel node biopsy involves injecting a dye, called tracer material, which helps the surgeon locate the sentinel nodes. The sentinel nodes are then surgically removed and analyzed in a lab by the pathologist.
If the sentinel node biopsy is negative (free of cancer), it indicates that cancer has not spread, and the rest of the nodes need not be removed. Hence, the procedure helps to determine if lymph node dissection (surgical removal) is required. If a sentinel lymph node biopsy reveals the presence of cancer, the doctor would typically advise removing the rest of the group of lymph nodes.
Why is sentinel node biopsy done?
Sentinel node biopsy is recommended for people with certain types of cancer that have a high risk of spreading to the lymphatic system and then to the rest of the body.
Sentinel node biopsy is routinely performed for people diagnosed with the following cancers:
Sentinel node biopsy may be performed for other types of cancer, such as:
How is sentinel node biopsy performed?
Before the procedure:
The doctor would advise routine laboratory and radiological tests to assess the general health status of the patient and their fitness for surgery. The first step of the sentinel node biopsy procedure is to locate the sentinel nodes by one of the following techniques:
- Radioactive solution: A weak radioactive solution is injected near the tumor that drains into the lymphatic system and travels to the sentinel nodes. This is usually done a few hours prior or the day before the sentinel node biopsy procedure.
- Blue dye: The doctor injects a safe, non-reactive blue dye near the tumor before the procedure, which drains into the lymphatic system and sentinel nodes, staining them blue.
During the procedure:
The procedure is usually performed under general anesthesia. The surgeon makes a small incision (cut) in the area over the lymph nodes. The blue dye or the radioactive solution injected before the procedure is the guide that helps the surgeon identify the sentinel nodes. There are usually one to five sentinel nodes and typically, all are removed. The sentinel nodes are sent to a pathologist to study under a microscope for signs of cancer.
After the procedure:
Most patients are discharged the same day after the procedure. Patients can return to their daily activities in 1-2 days or longer depending on their situation. Other specific activities may be resumed after consulting with the doctor. If the sentinel node biopsy was performed as a part of more extensive surgery to remove primary cancer, the hospital stay and recovery time would be longer.
What are the complications of sentinel node biopsy?
Sentinel node biopsy is generally a safe procedure. However, like any surgery, there is a risk of complications, including:
- Bleeding
- Pain
- Swelling and bruising
- Infection
- Allergic reaction to the dye
- Reaction to anesthesia
- Lymphedema (lymph vessels don’t drain fluid adequately causing fluid accumulation and swelling)