The lymphatic system
The lymphatic system helps protect us from infection and disease. Sometimes cancer cells can travel through the lymphatic system, to other parts of the body.
What is the lymphatic system?
The lymphatic system is part of the body’s immune system. It protects us from infection and disease. The lymphatic system is made up of:
-
Lymph vessels
Lymph vessels are a network of tiny tubes throughout the body. They carry lymph fluid.
-
Lymph fluid
This is a colourless fluid that flows through the lymph vessels. It is filtered through the lymph nodes. It then moves back into the bloodstream.
-
Lymph nodes (glands)
Lymph nodes act like a filter for the lymph fluid. They remove germs (bacteria and viruses) and other harmful cells.
Lymph nodes can be tiny like a pinhead or bigger like a baked bean. They are spread throughout the body. Some areas have groups of lymph nodes. These groups are mainly in the neck, armpits, groin, chest and tummy (abdomen).
You might sometimes be aware of your lymph nodes, such as the ones in your neck when you have a sore throat. They can feel sore or swollen for a short time while your body fights an infection. But if you notice a painless, swollen lymph node, it is important to get it checked by your GP.
Organs in the lymphatic system
The lymphatic system has several organs:
-
The spleen
This controls some of our blood cells. It filters out and removes old and damaged red and white blood cells. It also contains white blood cells. These help protect us from infection.
-
The thymus
The thymus is a small gland in the chest. It helps produce white blood cells. It is more active when you are a teenager and shrinks over time.
-
Tonsils and adenoids
These help protect the lungs and digestive system from infections. Tonsils sit at the back of the throat. Adenoids are at the back of the nose.
The lymphatic system
The lymphatic system of the head and neck
What does the lymphatic system do?
The lymphatic system has different jobs:
- It helps fight infection – inside the lymph nodes are white blood cells called lymphocytes. Lymphocytes attack and destroy bacteria, viruses, damaged cells and cancer cells. When lymph nodes are fighting an infection, they can get bigger and feel sore.
- It removes waste products – the lymphatic system carries destroyed bacteria and other waste products back into the bloodstream. The liver and kidneys remove these from the blood. The body then gets rid of this waste when you pass urine (pee) or stools (poo).
The lymphatic system and cancer
Cancer can affect the lymphatic system in different ways:
Cancer cells may travel through the lymphatic system
Sometimes cancer spreads from one place in the body (the primary site) to another place. It can travel through the blood or the lymphatic system. When the cancer moves to somewhere else, it is called a secondary cancer or metastasis.
Cancer cells may spread into and grow in the lymphatic system
Sometimes cancer from another part of the body can spread into and grow in the lymph nodes. This is called lymph node metastases or secondary cancer in the lymph nodes.
Cancer may start in the lymphatic system
Lymphoma is a cancer of the lymphatic system. It develops when white blood cells called lymphocytes become abnormal. The most common symptom of lymphoma is a painless swelling or lump in the neck, armpit or groin. If you notice this, it is important to get it checked by your GP.
Related pages
Do you need this information in another language or format?
We are committed to making our website as accessible as possible, to make sure that everyone can use it.
If you need Macmillan cancer information in another language, large print, or braille, we can help you. Just email us in English to tell us what information you need.
We also have information available in different formats including audiobooks, British Sign Language and easy read.
If you would like to speak to someone in your language, please call 0808 808 0000 and tell us, in English, the language you need.
About our information
-
References
Below is a sample of the sources used in our lymphatic system information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
DeVita Vincent T et al. DeVita, Hellman, and Rosenberg's Cancer. Wolters Kluwer, 2018. Available from oncology.lwwhealthlibrary.com/book.aspx?bookid=3236.
Hanahan D. Hallmarks of cancer: New dimensions Cancer Discovery, 2022. 12 (1): 31–46. Available from doi.org/10.1158/2159-8290.CD-21-1059.
-
Reviewers
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by members of Macmillan’s Centre of Clinical Expertise.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.
The language we use
We want everyone affected by cancer to feel our information is written for them.
We want our information to be as clear as possible. To do this, we try to:
- use plain English
- explain medical words
- use short sentences
- use illustrations to explain text
- structure the information clearly
- make sure important points are clear.
We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.
You can read more about how we produce our information here.
Date reviewed
Our cancer information meets the PIF TICK quality mark.
This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.
How we can help