Sometimes cancer or cancer treatment can damage the peripheral nerves, causing pain or numbness. The peripheral nerves are the nerves located away from the centre of the body, such as in the hands and feet. When these nerves don’t work properly, the medical term is “peripheral neuropathy”. Unlike other cells in the body, nerve cells are not easily repaired or replaced once they are badly damaged.
About the nervous system
The nervous system controls everything your body does. It has two main parts:
- the central nervous system – the brain and spinal cord
- the peripheral nervous system – a network of nerves that carries messages between the brain and spinal cord, and the body.
How nerves work
Nerves are made up of nerve cells called neurons. When a nerve ending is stimulated, a tiny electrical signal is sent from neuron to neuron, eventually reaching the spinal cord and brain.
When a peripheral nerve is damaged (for example, by chemotherapy), the electrical signals may be blocked or mixed up. This can lead to a wide range of symptoms.
When nerves don’t work properly
People whose nerves aren’t working properly may experience different symptoms, depending on which peripheral nerves are affected. No two cases are the same.
Most often, the nerve damage causes numbness, tingling (“pins and needles”) or pain in the hands and feet. If the condition worsens, these symptoms may start to spread further up the arms and legs.
There are other symptoms that may be caused by nerve not working properly:
- muscle weakness
- balance problems
- trouble sensing where your body is in space
- ringing in the ears
- hearing loss and constipation.
See Symptoms and effects for more information.
The symptoms range from mild to severe. They can appear during or after treatment, and they may be temporary or permanent. In more severe cases, the symptoms of nerve damage can greatly affect a person’s quality of life, but there are usually ways to manage any changes (see Diagnosis and treatment).
Some types of chemotherapy that are used to treat cancer can affect peripheral nerves. If this side effect occurs, you may hear it called “chemotherapy-induced peripheral neuropathy” (CIPN). Sometimes, other cancer treatments or the cancer itself can stop the peripheral nerves working properly.
There are a number of possible cancer-related causes for the peripheral nerves not working properly:
- certain chemotherapy drugs, in particular:
- taxanes, such as docetaxel and paclitaxel
- platinum drugs, such as carboplatin, cisplatin and oxaliplatin
- vinca alkaloids, such as vincristine
- some other cancer drugs, such as thalidomide, bortezomib and brentuximab vedotin
- some types of cancer, especially lung cancer, myeloma and lymphoma
- tumours pressing on nerves
- bones breaking down and causing swelling that presses on nerves
- surgery or radiation therapy damaging nerves.
It’s not just cancer that stops the nerves working properly. Nerves can be affected by a number of factors:
- heavy use of alcohol and other drugs
- a lack of certain vitamins and minerals, especially vitamin B.
These factors may also increase your risk of your nerves not working properly after a cancer diagnosis. Smoking is another factor that can increase the risk.
The main reason for nerves not working properly for people affected by cancer is treatment with certain chemotherapy drugs. For these types of chemotherapy, about 7 out of 10 people will experience some symptoms one month after treatment, and 3 out of 10 people will still have symptoms six months after treatment. The risk is different for different chemotherapy drugs.
Some types of chemotherapy affect the nerves for short periods during or shortly after the cancer treatment session. This known as “acute peripheral neuropahty”) and each episode tends. to last a few days.
For other types of chemotherapy, the effect may last longer ( this is called “chronic peripheral neuropathy”). It can start during treatment and is more likely to occur the more treatment cycles you have had. In some cases, nerve damage can develop or get worse over time, even after treatment has finished.
After the end of cancer treatment, symptoms may begin to improve over 6 to 12 months.
In some people, symptoms are permanent and may be severe. This is more likely if you have had intensive treatment, such as high-dose chemotherapy, or if you have diabetes or other risk factors.
So far, no treatment has been proven to prevent peripheral neuropathy. If you start having symptoms during chemotherapy treatment, your doctor may reduce the doses of chemotherapy drugs or give them to you further apart. This adjustment sometimes allows the nerves to recover and prevents permanent damage.
In some cases, you may need to stop having a certain chemotherapy drug. You can talk to your doctor about how they will balance the risk of changing the chemotherapy plan against the risk of the nerve damage becoming permanent.
Researchers are studying whether wearing ice mitts and ice booties during chemotherapy treatment could help prevent the cell damage that causes peripheral neuropathy. There is not yet enough evidence that this works.
Although there is no way to prevent peripheral neuropathy developing, you may be able to reduce your risk. If you have diabetes, it will be important to make sure the diabetes is well managed throughout your cancer treatment. Limiting how much alcohol you drink and not smoking may also lower the risk.
For more information, talk to your treatment team.
Reviewers: Dr Susanna Park, IN FOCUS research program and Senior Lecturer, Brain and Mind Centre, Faculty of Medicine and Health, The University of Sydney, NSW; Katrina Dick, Consumer; Rosemerry Hodgkin, 13 11 20 Consultant, Cancer Council WA; Phil Mendoza-Jones, Consumer; Jodie Nixon, Clinical Team Leader, Occupational Therapy, Cancer Services, Princess Alexandra Hospital, QLD; Rachel Tunney, Consumer; Jane Turner, Senior Exercise Physiologist, Sydney Cancer Survivorship Centre, Concord Hospital, NSW; Dr Shirley Wong, Consultant Medical Oncologist, Sunshine Hospital, Western Health, VIC