Although some ultrasound and/or CT scan studies may show that patients’ lymph nodes (glands) are free of disease, upon further examination using sentinel lymph node biopsies,(SLNB) the doctors at MD Anderson have found that approximately 20 to 30% of patients actually do have disease present in their lymph nodes.
SLNB allows the doctors to view the patient’s lymph nodes to determine the type of cancer, whether the disease has spread, and to decide on a treatment.
Head and neck surgeon Stephen Lai, M.D., Ph.D. Department of Head and Neck Surgery., Division of Surgery MD Anderson Cancer Center provided additional information.
About Sentinel Lymph Nodes
Dr. Lai explained that sentinel lymph nodes are a vital part of the immune system. They contain cells that look for foreign substances such as viruses, bacteria, and cancer.
Nodes that appear to be at risk to contain cancer are identified by sentinel lymph node mapping.
About Sentinel Lymph Node Biopsy (SLNB)
The doctors at MD Anderson generally use sentinel lymph node biopsy for breast cancer and melanoma. Recently the biopsy has begun to receive attention for head and neck cancers and gynecologic cancers.
SLNB is a minimally invasive procedure which identifies a lymph node that is in close proximity to a cancerous tumor as the sentinel node. The node is then removed and analyzed under a microscope.
If the SLNB is negative, in most cases this is an indication that cancer has not spread. If the SLNB report is positive, this means that cancer was detected in the lymph node and may exist in other lymph nodes or organs. Additional information about sentinel lymph nodes and SLNB is available here.
About the SLNB Procedure
Dr. Lai explained that SLNB is a personalized surgery that is tailored to each patient with the goal of targeting the lymph nodes that are most likely to be cancerous.
A radiotracer is injected by the surgeon around the site of the tumor and flows through the lymphatic system to the first draining (sentinel) nodes.
About SLNB Biopsy Benefits
- Smaller incision
- May prevent more invasive surgery
- Shorten postoperative recovery time
- Lowers the risk of side effects
One of the side effects is lymphedema, the localized fluid retention and tissue swelling that is generally associated with some cancer treatments.
The SLNB is usually performed as an outpatient procedure with the patient able to leave the hospital the same day.
What Risks are Involved With SLNB?
Occasionally SLNB is unable to identify a sentinel lymph node, but in general the risks are low. The radiotracer uses a very low-energy emission particle.
To date, there have not been any severe adverse reactions reported, although some patients have experienced rare episodes of brief pain when receiving the injection.
Helping More Cancer Patients Using SLNB
Dr. Lai explained that after he completed a Phase III clinical trial, the FDA approved a new radiotracer that is now being used in patients with oral cavity cancers that originate in tissues of the mouth.
His next effort in this regard is to start a Phase III clinical trial comparing elective neck dissection, a more traditional technique, to SLNB in early-stage oral cavity cancer patients.
Although sentinel lymph node biopsy has been widely accepted for the treatment of breast cancer and melanoma, it is more widely accepted in Europe than in the U.S. for early-stage oral cavity cancer. However, its use in the U.S. is steadily increasing.
It is noteworthy that Michael Frumovitz, M.S., of MD Anderson used a new type of dye in sentinel lymph node detection for patients with uterine and cervical cancers. This Phase III clinical trial has recently been completed.
Dr. Lai said the procedure is designed to detect cancer effectively and more accurately in an effort to help the patients keep their quality of life.