When do swollen lymph nodes mean cancer?

The simplest answer would be – hard to say! While some general indications are there, these are not enough to confirm or rule out cancer.  There are some physical markers in which case cancer is suspected. The lymph node could be large in size, irregular in outline, firm or hard, or rubbery or not very mobile. However, these are not enough to confirm cancer. In the same way, absence of such markers does not mean, there is no cancer. That is why more tests are done to confirm or rule out cancer(s).

To know more about this, we need to understand what is the lymphatic system is and how does it work?

What is the lymphatic system?

Among all the body-systems, people have the least awareness about the lymphatic system. Yet it’s one of the most important systems for our overall health and well-being. It’s part of the body’s immune system and is responsible for maintaining a good level of immunity against disease.

The lymphatic system primary consists of thin, tubular, vein-like ‘lymph vessels’, in which a thin, clear fluid called the ‘lymphatic fluid’ flows, and small, kidney-bean shaped, lymph nodes. Clusters of lymph nodes are present throughout the body. They are close to the surface of the skin, behind the ears (auricular lymph nodes), in the neck (cervical), near the collar-bone (supraclavicular), upper chest (subclavian), chest (pectoral), at the armpits (axillary), at the elbow (epitrochlear) and the groin (inguinal). These can be felt to the touch by a doctor. Other than these, there are several clusters deep inside the body which cannot be seen or felt. Overall, there are approximately 600 clusters estimated to be present in a normal, healthy, adult human body.

Why do lymph nodes swell up?

The working of the lymphatic system can be best understood by comparing it with the criminal-policing system. The lymph vessels are like the highway in which white blood cells, that act as patrol police, flow through. Pathogens like viruses and bacteria, cancerous cells and other toxic materials are like criminals that get onto the highway and try to harm the body. That is, invading cells attach themselves or penetrate blood vessels and lymph vessels in an attempt to harm the body.

If white blood cells (patrol police) are not able to destroy the infiltrating pathogens, they are able to get away but eventually arrive at check-points called lymph nodes. Here, more white blood cells (more police) try to attack or stop the invaders, causing a build-up of cops and criminals – white blood cells and invading cells at the lymph node. That is when, or that is why, the lymph node gets swollen up. It’s a clear indication that there are invaders – infections or disease-causing pathogens in the body. (You may remember doctors trying to feel the underside of your throat when you have a fever. They are basically looking for swollen cervical lymph nodes.)

That is why the lymph vessels, lymphatic fluid and lymph nodes are compared to filters as they filter out invading pathogens. They are also compared to sewerage drains as they drain out the waste in the body. This is because the lymph vessels generally drain into blood vessels, from where the waste material is transported by blood to the liver and kidneys (sewage treatment plants) for breakdown and elimination.

The clusters of lymph nodes are distributed throughout the body, in order to filter out invading cells in the vicinity, which makes perfect sense. So if lymph nodes in the throat are swollen, it’s an indication of cold or viral infections, if swollen in the groin area, an indication of sexually transmitted disease, etc. In exactly the same way, cancerous cells in the proximity of a cluster of lymph nodes will cause that cluster to swell up. However, every lymph node swelling is not cancer and there are many conditions that cause this.

Conditions that cause lymph node swelling

Common infections

• Ear infections
• Infected or abscessed tooth
• Measles
• Strep throat
• Skin or wound infections like cellulitis
• Mononucleosis, a condition caused by the Epstein-Barr virus
• Human immunodeficiency virus (HIV) which causes AIDS

Uncommon infections

• Tuberculosis
• Toxoplasmosis: an infection caused by parasites that enter the body subsequent to contact with the feces of an infected cat or from eating undercooked meat
• Sexually transmitted infections like syphilis
• Cat scratch fever: a bacterial infection caused by a cat scratching or biting the person

Immune system disorders

• Lupus: marked by chronic inflammation in the heart, lungs, kidneys, joints, skin and blood cells
• Rheumatoid arthritis: marked by chronic inflammation of the synovium, a tissue that lines our joints

Cancers

• Lymphoma: here the cancer has originated in the lymphatic system itself
• Leukemia: cancer of the tissues that form blood – such as the bone marrow, and lymphatic system
• Metastasized cancers: Cancers that started in other organs or parts of the body and spread to the lymph nodes

Diagnosis and Treatment

• Personal medical history: The doctor will try to understand when and how the lymph nodes got swollen, and check other signs and symptoms.
• Family medical history: The doctor will want to know if you or any of your family members have a history of cancer or any of the conditions listed above
• Physical examination: The doctor will look at and feel the size, texture, warmth and tenderness of the lymph nodes near the skin.
• Blood tests. A complete blood count (CBC) and other targeted tests are done to check for specific underlying conditions such as infections or leukemia.
• Imaging tests: An X-ray or CT scan of the affected area is done to identify possible sources of infection, or detect tumors.
• Lymph node biopsy: If none of the above tests are conclusive, the doctor may order for a biopsy of one or more swollen lymph nodes. A small sample of tissue from such nodes are extracted using a fine needle and examined under the microscope.

Treatment options vary depending on the underlying conditions. Common infections are treated by antibiotics, OTC drugs and home-remedies. Uncommon infections and immune disorders are treated by drugs and therapies that are targeted at them. Cancers are treated through multiple options such as radiation, chemotherapy and surgery.

Outlook

If you or any of your dear ones are showing swollen lymph nodes or any other symptoms of disease, do not panic. Rush to a reputed hospital. Here, specialists will conduct the required tests, diagnose the condition precisely and prescribe the right course of treatment for quick recovery and rehabilitation.

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Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals

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Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.

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