Cancer's journey within the body is complex and involves a network of organs and processes. While the primary tumour itself is a cause for concern, understanding its potential for spread is crucial for effective treatment planning. This is where sentinel lymph nodes play a vital role. In this blog, we’ll talk about the role of sentinel lymph nodes in breast cancer, biopsy of sentinel nodes, and much more!

What Is The Lymphatic System?

Imagine a network of interconnected channels and tiny filters spread throughout your body. This is the lymphatic system, a vital part of your immune system responsible for:

• Draining fluid: Excess fluid from tissues, including waste products and immune cells, enters the lymphatic system.
• Filtering toxins: Lymph nodes act as filters, trapping bacteria, viruses, and other harmful substances.
• Transporting immune cells: White blood cells travel through the lymphatic system to fight infections and respond to threats.

What Are Sentinel Lymph Nodes?

Within this network, specific lymph nodes hold a critical position: sentinel lymph nodes. These are the first lymph nodes that receive drainage from a specific area, making them the most likely to be affected if cancer cells spread from a nearby tumour. Studies conducted in India suggest that the sentinel lymph node positivity rate in breast cancer patients undergoing SLNB falls around 28-30%.

Importance of Sentinel Lymph Nodes in Breast Cancer

The significance of sentinel lymph nodes lies in their ability to provide valuable information about cancer spread:

• Early detection: Identifying cancer in the sentinel node suggests a higher likelihood of cancer spread beyond the primary tumour.
• Guiding treatment decisions: A negative sentinel lymph node biopsy (SLNB), meaning no cancer is found, often allows for less extensive surgery and potentially less aggressive treatment options.
• Improving prognosis: Knowing the cancer status of the sentinel node helps doctors predict the overall outcome and tailor treatment plans accordingly.

How Do We Find Sentinel Lymph Nodes?

Two main methods are used to locate sentinel lymph nodes:

• Radioactive tracer: A small amount of radioactive material is injected near the tumour site. This tracer follows the same pathway as fluid, allowing doctors to identify the sentinel node(s) through a special scanner.
• Dye injection: A blue dye is injected near the tumour and gets carried to the sentinel node, making it easier to visualise during surgery.

Procedure of Biopsy of Sentinel Lymph Nodes

The biopsy of Sentinel Lymph Nodes involves:

• Making a small incision: Usually near the tumour site.
• Removing the sentinel node(s): These are then sent to a laboratory for analysis.
• Closing the incision: Stitches or staples are used to close the wound.

Benefits of Sentinel Lymph Node Biopsy

The benefits of SLNB include:

• Reduced surgical complications: Compared to extensive lymph node removal, SLNB offers a smaller incision and faster recovery.
• Improved quality of life: Less extensive surgery can minimise side effects, such as arm pain and swelling in cases of breast cancer.
• More precise treatment: Knowing the extent of cancer spread allows for personalised treatment plans.
• Reduced Morbidity: Compared to traditional lymph node dissection, which removes a larger group of nodes, SLNB offers a less invasive option, leading to faster recovery and fewer potential complications like lymphedema (fluid buildup).
• Improved Treatment Decisions: A positive SLNB indicates the cancer has likely spread beyond the original tumour, potentially influencing treatment decisions, such as the need for additional surgery, chemotherapy, or radiation therapy. Conversely, a negative SLNB suggests a lower risk of cancer spread, potentially allowing for less aggressive treatment approaches.
• Personalised Treatment: The information gained from SLNB allows for a more personalised treatment plan tailored to the individual's specific needs and disease stage.

It's important to note that SLNB is not suitable for all types of cancer or all stages. Consulting a healthcare professional is crucial to determine the best course of action based on individual circumstances.

The Process of Sentinel Lymph Node Biopsy

The process of SLNB typically involves several steps:

1. Mapping: Prior to surgery, a specialised technique, often using a radioactive tracer or dye, helps identify the sentinel lymph node(s).
2. Surgery: During surgery, the surgeon removes the identified sentinel lymph node(s).
3. Pathological Examination: The removed lymph node(s) are sent to a laboratory for analysis by a pathologist to determine the presence or absence of cancer cells.

Who is a Candidate for Sentinel Lymph Node Biopsy?

The decision to perform an SLNB is based on various factors, including the type and stage of cancer, the patient's overall health, and individual risk factors. It's crucial to discuss the risks and benefits of this procedure with a healthcare professional to understand if it's the right course of action for your specific situation.

The Future of Sentinel Lymph Nodes in Medical Industry

Research on sentinel lymph nodes is ongoing, exploring their potential in:

• Developing new diagnostic tools: Using genetic or molecular markers to identify cancer spread with greater accuracy.
• Personalised medicine: Tailoring treatment based on the specific characteristics of the cancer cells found in the sentinel node.
• Minimally invasive treatment: Utilising techniques like laser ablation to destroy cancerous cells within the sentinel node itself.

Understanding sentinel lymph nodes empowers individuals facing cancer by providing valuable information for personalised treatment plans. By recognizing their importance, we can navigate this complex journey with greater knowledge and hope.

Challenges and Controversies

While SLN biopsy is a valuable tool in cancer diagnosis and staging, it is not without challenges. One challenge is the risk of false-negative results, where cancer cells are present in the SLNs but are not detected. There is also controversy surrounding the use of SLN biopsy in certain cancers, with some studies suggesting that it may not always be necessary and could lead to overtreatment.

Final Thoughts

Sentinel lymph nodes play a vital role in the potential spread of cancer and serve as valuable targets for diagnosis and treatment. Understanding their function and the significance of sentinel lymph node biopsy empowers both patients and healthcare professionals to make informed decisions about cancer management. As research continues to explore the potential of these essential nodes, their role in improving cancer care is likely to continue to evolve.