Melanoma is a type of skin cancer that can spread to the surrounding organs and cause death.
Melanoma is a type of skin cancer that can spread to the surrounding organs and cause death. A sentinel lymph node biopsy (SLNB) is done in patients with melanoma to investigate the spread of the disease.
SLNB is generally performed for melanoma when one or more of the following are true:
- Melanoma is equal to or greater than 1 mm in depth
- Presence of an ulcerated tumor of any thickness
- Invasion of cancer cells to the lymphatic channels or blood vessels
- Margins taken during biopsy reveals melanoma
However, SLNB should not be considered during the following conditions:
- The size of melanoma is less than 0.76 mm and presents no risk factors
- If melanoma extended to lymph node is in stage III
- The melanoma has spread to distant organs (stage IV)
What is a sentinel lymph node biopsy?
A sentinel lymph node biopsy (SLNB) is a specialized procedure to identify, remove, or examine any cancer cells present in the sentinel lymph nodes. It is usually performed in people diagnosed with melanoma cancer. If melanoma spreads, it will first extend to the nearest lymph node, that is, the sentinel lymph node.
Melanoma first extends to a group of lymph nodes known as the sentinel lymph nodes. Most of the individuals usually have between one and five sentinel lymph nodes.
A positive SLNB indicates that cancer has spread to the sentinel lymph nodes or other nearby lymph nodes. It also helps the physician to determine the exact stage of cancer and develop an appropriate treatment plan for the same.
Enlarged, irregular, firm, and palpable nodes may require a fine needle aspiration biopsy rather than SLNB.
How is a sentinel lymph node biopsy performed?
A sentinel lymph node biopsy (SLNB) has two parts:
- Lymphatic mapping
- Surgical procedure
Lymphatic mapping or lymphoscintigram usually involves injecting radioactive dye in the skin around the site of the original melanoma. The physician then with the help of a special camera locates the radioactive material as it travels from the original melanoma site to the sentinel lymph nodes.
After the completion of lymphatic mapping, the physician injects a second blue dye to visualize the lymph nodes already located by the specialized camera. The physician removes the sentinel lymph nodes and sends it for examination.
Another procedure for a biopsy includes wide local excision. In this, the physician removes the melanoma along with the biopsy tissue and some normal tissue surrounding it.
What are the outcomes of a sentinel lymph node biopsy?
After examination of the biopsied tissue, the sentinel lymph node may show evidence of melanoma in them. If the sentinel lymph nodes don’t show any evidence of melanoma, it is improbable that cancer has spread to the remaining lymph nodes, and no further surgery is needed. Completion lymph node dissection (CLND) is the complete removal of the affected sentinel lymph nodes and remaining lymph nodes in that area and is useful if one or more of the sentinel lymph nodes is positive for melanoma.
What are the complications of a sentinel lymph node biopsy?
The complications of a sentinel lymph node biopsy (SLNB) include: