From the Guidelines
Sentinel lymph node biopsy is a recommended staging procedure for patients with intermediate-thickness melanoma, as it provides accurate staging and can help decrease rates of recurrence in regional nodes, as supported by the American Society of Clinical Oncology and Society of Surgical Oncology clinical practice guideline update 1.
Definition and Purpose
Sentinel lymph node biopsy is a surgical procedure used to determine if cancer has spread beyond the primary tumor to the lymphatic system. During this procedure, the surgeon identifies and removes the sentinel lymph node—the first lymph node to which cancer cells are likely to spread from the primary tumor.
Procedure Details
This is done by injecting a radioactive substance, blue dye, or both near the tumor, which then travels through the lymphatic system to the sentinel node, making it identifiable during surgery. Once removed, the sentinel node is examined by a pathologist for cancer cells.
Benefits and Indications
If no cancer is found, it suggests that cancer has not spread to the lymphatic system, potentially eliminating the need for more extensive lymph node removal. This procedure is commonly used in melanoma cases, as it provides valuable staging information while being less invasive than complete lymph node dissection, resulting in fewer complications. The updated guideline also recommends considering SLN biopsy for patients with thick melanoma and those with T1b lesions (0.8 mm to 1.0 mm thickness regardless of ulceration status or ulcerated melanoma, 0.8 mm) for staging purposes and possible therapeutic effect, as shown in the MSLT-I results 1.
Key Considerations
The accuracy of sentinel lymph node biopsy depends on the surgeon's experience and the type of cancer being treated. The procedure has been found to have low false-negative rates and high rates of sentinel node detection, making it a useful tool in the management of melanoma 1.
From the Research
Definition and Purpose of Sentinel Lymph Node Biopsy
- Sentinel lymph node (SLN) biopsy is a procedure that involves the detection and pathological examination of the first node to receive drainage directly from a tumor 2.
- The purpose of SLN biopsy is to minimize morbidity related to extensive nodal dissection while providing important information for cancer staging and treatment planning.
Clinical Applications of Sentinel Lymph Node Biopsy
- SLN biopsy has become the standard surgical treatment in patients with malignant melanoma, breast, vulvar, and cervical cancers 2.
- It is also being evaluated for its use in lung cancer, with ongoing discussions on its role and techniques for identifying and evaluating the sentinel node 3.
- In breast cancer, SLN biopsy has become a standard staging tool, with a positive impact on postoperative outcomes without compromising oncological outcomes 4.
Techniques and Technologies Used in Sentinel Lymph Node Biopsy
- Various techniques are used to identify the sentinel node, including the use of blue dye, radioisotope, and near-infrared fluorescence (NIR) 2, 5.
- New technologies, such as fluorescent dyes indocyanine green (ICG) and pathologic ultrastaging, have improved the detection rate and reduced the false-negative rate of SLN biopsy 2.
- The use of radiotracers, such as 99mTc-Tilmanocept, is also being explored for its potential to overcome the shortcomings of conventional radiotracers used in SLN biopsy 6.