Sentinel Lymph Node Biopsy

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: Jerry R. Balentine, DO, FACEP
    Jerry R. Balentine, DO, FACEP

    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

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What is a sentinel lymph node biopsy?

The sentinel lymph nodes are the first few lymph nodes ("lymph gland") to receive lymphatic drainage from a tumor, meaning that sentinel lymph nodes are the first lymph nodes to which cancer cells would spread. It stands sentinel over the tumor, so to speak. The biopsy is performed to determine if there are tumor cells in the node. If the sentinel lymph node does not contain tumor cells (a negative result), then the cancer has not likely spread to lymph nodes or other organs via the lymphatic system.

What is the lymphatic drainage?

Lymphatic system refers to a collection of vessels that, like the system of blood vessels, circulates fluid through the tissues. The lymphatic drainage refers to the manner in which tissue fluid, or lymph, is drained from the body and returns to a central location -- in this case, a lymph node. The lymphatic fluid has a milky appearance.

Why do a biopsy of the sentinel node?

Examination of the sentinel node ("gland") is performed to learn whether that node does or does not have tumor cells within it. The biopsy is performed to verify if there are tumor cells present. This procedure helps the surgeon accurately stage the tumor. Staging a tumor refers to determining the extent to which it has spread in the body.

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Do you know what you should ask your doctor before you have a biopsy?

Questions to Ask Your Doctor Before a Biopsy

A biopsy is a sample of tissue removed by your doctor to make a precise diagnosis. Biopsy procedures can range from a simple sampling of skin under local anesthesia to surgical opening of the chest wall to remove a portion of lung tissue. Biopsies may also be obtained during diagnostic procedures such as endoscopy, colonoscopy, bronchoscopy, and others. Sometimes doctors perform biopsies using a CAT scanor other radiological imaging techniques to help identify the exact area to be sampled and avoid injury to surrounding organs. There are several types of biopsies.

How does a tumor spread?

Tumors have only three ways of spreading:

  • by local invasion of adjacent tissue,
  • through the blood stream, and
  • through the lymphatic system.

Some tumors spread preferentially by the lymphatic system, meaning that they tend to spread by this method.

How is it determined which is the sentinel node?

Which lymph nodes are the sentinel nodes for a given tumor is determined by injecting around the tumor a tracer substance that will travel through the lymphatic system to the first draining (sentinel) nodes and identify them. The tracer substance may be blue dye that can be visually tracked or a radioactive substance that can be detected as with a Geiger counter or both.

What types of specialists perform a sentinel lymph node biopsy?

Sentinel lymph node biopsy is performed by surgeons. This procedure is most commonly performed to evaluate breast cancers and melanomas so breast surgeons will perform this procedure, as well.

What happens during a sentinel lymph node biopsy?

After the tracer substance is injected, the surgeon identifies the sentinel lymph node and surgically removes it through a small incision. This may be done in an outpatient surgery center or a hospital operating room. Sentinel lymph node biopsy is often done at the same time as the removal of a primary tumor.

What does the sentinel lymph node biopsy show?

Biopsy of the sentinel lymph node can reveal whether there are or are not lymphatic metastases, which are tumor cells that have journeyed from the original primary tumor into the lymphatic drainage system. The sentinel node can be rapidly evaluated while the patient is still in surgery utilizing the technique of frozen section analysis. The final report on the sentinel node awaits the final analysis by the pathologist on what is called formalin fixed tissue.

If the sentinel node contains tumor cells, removal of more nodes in the area may be warranted. This may be done during the same procedure if the first sample is evaluated while the patient is still in the operating room. If the sentinel node is normal, it is unnecessary to perform an extensive dissection of the regional lymph-node basin.

What are the benefits of a sentinel lymph node biopsy?

The sentinel node biopsy allows the examination of one lymph node to first determine if a tumor has spread to the lymph nodes at all. If the sentinel node is negative for tumor cells, it is not necessary to surgically remove additional lymph nodes. The procedure helps certain patients avoid more extensive surgical procedures involving the removal of multiple lymph nodes, such as axillary lymph node dissection in patients with breast cancer.

What are the side effects and complications of a sentinel lymph node biopsy?

The most common side effects are short-term bruising, pain, or swelling at the surgical site. As with any surgery, bleeding and infection are possible complications. Another possible risk is a false-negative result, which means that tumor cells are present but not detected by the procedure. Studies with breast cancer patients have shown false-negative rates of around 10%.

Is the use of the sentinel lymph node biopsy common?

Yes. Sentinel lymph node biopsy has, for example, become a standard technique for determining the nodal stage of the disease in some patients with malignant melanoma and with breast cancer. The use of sentinel node biopsy is still being investigated with other types of cancer.

What is the recovery time after a sentinel lymph node biopsy?

The recovery time varies, depending on whether or not the sentinel node biopsy is associated with removal of the primary tumor and the extent of surgery required. In any case, sentinel lymph node biopsy offers a quicker recovery time than a more extensive lymph node dissection.

REFERENCE:

United States. National Cancer Institute. "Sentinel Lymph Node Biopsy." Aug. 11, 2011. <http://www.cancer.gov/about-cancer/diagnosis-staging/staging/sentinel-node-biopsy-fact-sheet>.

Last Editorial Review: 8/29/2016

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Reviewed on 8/29/2016
References
REFERENCE:

United States. National Cancer Institute. "Sentinel Lymph Node Biopsy." Aug. 11, 2011. <http://www.cancer.gov/about-cancer/diagnosis-staging/staging/sentinel-node-biopsy-fact-sheet>.

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