Peripheral neuropathy (also called neuropathy) is a term used to describe damage to nerves that are outside of the brain and spinal cord (peripheral nerves).

Peripheral neuropathy is not one specific disease. Many different conditions that can damage the peripheral nerves can cause it. This information is about cancer related causes of peripheral neuropathy and mainly on neuropathy caused by anti-cancer drugs.

The nervous system is made up of the brain, the spinal cord and a network of nerves that thread throughout the body. It has two main parts:

• the central nervous system (CNS), which is made up of the brain and spinal cord
• the peripheral nervous system (PNS), which is made up of nerves that carry messages between the brain, the spinal cord and the rest of the body.

Nerves carry nerve impulses back and forth between the body and the brain.
They are made up of nerve cells called neurons. Some neurons are very small, but others can be up to 3 feet (1metre) long.

When a nerve ending is stimulated, for example by heat, touch, or sound vibrations, it creates a tiny electrical pulse. This sends a signal along the nerve cell. When it reaches the end of the cell, the signal triggers the release of chemicals.

These carry the signal to the next nerve cell. In this way, messages can be sent from nerves anywhere in the body to the spinal cord and then up to the brain.

There are different types of nerves:

Motor nerves carry messages from the brain to the muscles. When a muscle receives a message, it reacts with a movement. Messages can be sent from the brain to any part of the body.

Sensory nerves carry messages from the body to the brain. These nerves have endings (receptors) that are sensitive to sensations such as pain, temperature, touch and vibration. They enable us to feel different sensations.

Although we are not aware of it, our brain is constantly receiving messages from sensory nerves throughout our body. These messages tell our brain where each part of our body is and are important for balance, coordination and walking.

Autonomic nerves carry messages back and forth between internal organs and the brain. They control the actions of muscles that aren’t under our voluntary control. They are responsible for maintaining our blood pressure, and for the workings of our bowel and bladder.

There are several ways in which cancer and treatments for cancer may cause peripheral neuropathy:

• Some anti-cancer drugs can cause nerve damage. This is the most common cause of peripheral neuropathy in people with cancer.
• Cancer can cause peripheral neuropathy in one area of the body if the tumour is growing close to a nerve and presses on it.
• Surgery may damage nerves and cause symptoms in the affected area; for example, numbness or tingling and pain in the arm after breast cancer surgery.
• Rarely, radiotherapy may damage nerves within the treated area, causing symptoms such as numbness and weakness. These may develop months or years after treatment.
• Occasionally, in some types of cancer, the body makes substances that damage peripheral nerves. This is called paraneoplastic peripheral neuropathy. It most commonly occurs in people with cancers of the lung, breast or ovaries, and in people with myeloma or Hodgkin lymphoma.

The symptoms of peripheral neuropathy vary depending on which nerves are affected. Anti-cancer drugs that cause nerve damage are most likely to affect sensory nerves but some can also affect the motor nerves and the autonomic nerves.

Peripheral neuropathy often affects the hands, feet and lower legs. This is because the longer a nerve is, the more vulnerable it is to injury. Nerves going to the hands, feet and lower legs are some of the longest in the body.

Symptoms of peripheral neuropathy are usually mild to begin with and gradually get worse.

Symptoms may include:

A change in sensation A feeling of heaviness, burning or pins and needles in the affected area. Alternatively, you may notice unusual sensations such as a feeling of warmth or burning when touching something cold.

Increased sensitivity You may find that even the lightest touch or pressure in the affected area feels uncomfortable or painful.

Pain This can be mild or more severe. The pain may be felt as sharp and stabbing or as a burning sensation, or it may feel like minor electric shocks. There are treatments to help to relieve pain.

Numbness There may be a loss of sensitivity or feeling in the affected area. Often the feet and fingertips are the first places to be affected.

Muscle weakness A muscle may lose strength if it isn’t being stimulated by a nerve. Depending on which muscles are affected, this may make it difficult to walk, climb stairs or do other tasks. You may be given physiotherapy or special exercises to help with this.

Difficulty buttoning clothes or picking up small objects If the nerve endings in the fingers are affected, you may not be able to do ‘fiddly’ tasks such as fastening small buttons or tying shoelaces.

Difficulty with balance, walking and coordination You may find that you stumble or trip when walking. Walking on uneven surfaces may be particularly difficult. You may feel clumsy at times, or that your body is not doing what you want it to do. Your sense of where things are around you may become less certain.

Constipation and feeling bloated Drinking at least two litres (three and a half pints) of fluid a day, and increasing the fibre in your diet may help to prevent constipation. If it does develop, you can contact your doctor or nurse for advice. You may need to take laxatives or other treatment prescribed by your doctor.

Feeling lightheaded or dizzy when you stand up Standing up more slowly may help as it gives your body more time to adjust to the change in position.

There are many different chemotherapy drugs. The types that most frequently cause peripheral neuropathy are:

• Vinca alkaloids: these include vinblastine (Velbe®), vincristine (Oncovin®), vinorelbine (Navelbine®) and vindesine. Vincristine is the most likely one of these drugs to cause peripheral neuropathy.
• The platinum based drugs cisplatin, oxaliplatin (Eloxatin®) and carboplatin (Paraplatin®).
• Taxanes docetaxel (Taxotere®) and paclitaxel (Taxol®).

Other anti-cancer drugs that may cause peripheral neuropathy include thalidomide, bortezomib (Velcade®) and alpha interferon.

Are some people more at risk of peripheral neuropathy when having these drugs?

You may be at higher risk if you:

• Are having more than one type of drug or treatment that can cause nerve damage.
• Have had previous anti-cancer drugs that can cause peripheral neuropathy.
• Have diabetes.
• Have low levels of certain minerals and vitamins (such as vitamin E, and B-vitamins). This may be because of diet, how much alcohol you drink, or for another reason.

What can I do to reduce my risk?

Let your doctor know if you think you drink quite a lot of alcohol. Taking vitamin B1 tablets can help to prevent nerve damage in this situation. Your doctor can prescribe these for you.

If you think your diet may be low in vitamins or minerals, talk to your doctor about whether you should take vitamin supplements. It’s important not to take high doses of vitamins or minerals without your doctor’s knowledge, in case this interferes with how well your treatment works.

If you already have peripheral neuropathy and need to have chemotherapy, there are a large number of chemotherapy drugs that do not cause or aggravate peripheral neuropathy. Your doctor can discuss the possible options with you.

If you are being given a drug that can cause peripheral neuropathy, your doctor will monitor you for signs of nerve damage before each treatment. Symptoms are often mild to begin with and gradually become more troublesome and severe. The earlier that nerve damage is detected, the better. It is therefore important to tell your doctor if you notice any new symptoms that may be caused by the treatment or if your symptoms are getting worse.

If an anti-cancer drug is causing peripheral neuropathy, your doctor will assess how much your nerves are affected. This information helps them to decide whether to continue your treatment, reduce the dose or stop the drug. There are various ways your doctor may assess your symptoms:

• Finding out how your symptoms are affecting your daily activities
• Establishing your ability to sense where parts of your body are when your eyes are closed.
• Checking whether the reflexes in your ankles, knees and wrists are working. Everyone has points on our body which, if hit gently with a rubber hammer, will normally respond with an automatic (reflex) movement.
• Testing for numbness or loss of sensation (pinprick test). This test measures whether you have lost some or any feeling in particular areas of the body such as the feet, lower legs and hands. You will be asked to say if you can feel a pin gently touching your skin in the areas of your body that may be affected by nerve damage.
• Assessing your balance and coordination; for example, by asking you to walk in a straight line.

Other, more specialised, tests are also sometimes done:

Nerve conduction studies assess the number of nerve cells that are working, and test the speed at which your nerves conduct an impulse.

Electromyography (EMG) records the response of the nerve or muscle to an electrical impulse.

Management of peripheral neuropathy There isn’t a treatment to prevent or reverse nerve damage caused by anti-cancer drugs. Studies are looking at various drug treatments, such as amifostine and xaliproden to see if they can help to protect against nerve damage during anti-cancer treatment. There are also studies looking into whether any treatments can reverse nerve damage that has occurred. But, at the moment, there isn’t enough evidence that any of these drugs work.

The most effective treatment for peripheral neuropathy is to prevent further damage to the nerves. Sometimes, it can help to lower the dose of the drug, that is causing the problem. If your symptoms continue to get worse, your doctors may have to stop the drug.

In most people, symptoms gradually improve once the drug is stopped, but they can sometimes continue to get worse for a few weeks. This is known as coasting.

Stopping treatment because of symptoms can be very difficult for some people to accept, especially if the treatment is working well. Your doctors will usually discuss with you whether another type of anti-cancer drug can be given instead.

Alternatively, some other kind of treatment – such as radiotherapy – may be suggested. It is extremely important not to stop treatment without first talking to your cancer specialist.

Most people find that their symptoms gradually improve with time as the nerves slowly recover. This may take several months or more. For some people, nerve damage will be permanent. But, in this situation, many people find that their symptoms become less troublesome over time, as they adapt and find ways of coping with the changes.

If you have nerve pain, sometimes called neuropathic pain, this can be managed in a number of ways.

Drugs Some types of drugs can alter nerve impulses and so help to relieve nerve pain. Drugs that act in this way include antidepressants, anticonvulsants (drugs that are used to treat epilepsy) and some heart drugs. So, if your doctor suggests an antidepressant drug, this is because of the way it acts on nerves, and not because they think that the pain is in your mind. Drugs such as morphine can also sometimes be helpful.

Injections A local anaesthetic may be injected around the damaged nerve. The anaesthetic works by blocking pain impulses for several days or weeks.

Transcutaneous electrical nerve stimulation (TENS) This may help to reduce pain. TENS uses pads, put onto the skin, that give off small electrical pulses. This causes a tingling sensation, which aims to stimulate nerves close to the area where the pain is. It is thought that this may work by blocking pain messages from being carried along the nerves to the brain. TENS is unlikely to cause any side-effects, so can be worth trying.

Acupuncture Acupuncture uses very fine needles that are placed through the skin at particular points. It isn’t clear exactly how this works but it may help to block pain messages from being sent to the brain.

Psychological support This may help to reduce the anxiety, tension and fear caused by the pain and can make it more bearable. This kind of support can be offered by psychotherapists and counsellors.

If your symptoms are mild, you may not need any additional help in managing them. But, if you have more troublesome symptoms, support is available to help you cope with these.

A physiotherapist will be able to offer treatment and advice if you are having problems with coordination, muscle weakness, balance, or walking.

If you are having difficulty in carrying out daily tasks because of peripheral neuropathy, you can ask to be referred to an occupational therapist. They will be able to assess your needs and recommend appropriate aids and equipment to help you. There are organisations which provide equipment for people who need help with daily tasks.

If symptoms continue for more than six months and cause you difficulty in walking or in carrying out daily activities you may be entitled to financial help. You may be able to claim Disability Living Allowance (if you are younger than 65) or Attendance Allowance (if you are older than 65). Your doctor, or a social worker or welfare rights officer may be able to advise you, or you can call the Disability Benefits Helpline on 08457 123 456.

If your hands or feet are affected, it is important to protect them as much as possible.

• Keep them warm (wear gloves and warm socks in cold weather).
• Wear gloves when working with your hands – for example when gardening or washing-up.
• Use potholders and take care to avoid burning your hands when cooking.
• Wear well-fitting shoes or boots.
• Avoid walking around barefoot and check your feet regularly for any problems.
• Test the temperature of water with your elbow to make sure it isn’t too hot before baths, showers or doing the washing-up. Turn the temperature control to a lower setting for hot water or have a temperature control (thermostat) fitted.

If your balance, coordination or walking is affected, you may be at more risk of accidents and falls.

• Make sure rooms are well lit, and always put on a light if you get up during the night.
• Keep areas that you walk through, such as halls, free of clutter and make sure there aren’t things such as loose rugs you could trip over.
• Get advice from a physiotherapist about walking aids if your balance is affected.

How peripheral neuropathy affects each person and how much practical and emotional support is needed to cope with it varies from person to person. You may find that your life is not affected very much, or, you may have many more challenges and difficulties to cope with.

If the peripheral neuropathy is severe and causing changes to your lifestyle, it is natural to feel isolated and frustrated. You may have different emotions, including anger, resentment, guilt, anxiety and fear.

These are all normal reactions and are part of the process many people go through in trying to come to terms with side effects caused by their treatment.

This section has been compiled using information from a number of reliable sources including:

• The Chemotherapy Source Book (4th edition). Perry, Lippincott Williams and Wilkins, 2007.
• Albers J, Chaudhry V, Cavaletti G, Donehower R. Interventions for preventing neuropathy caused by cisplatin and related compounds. Cochrane Database of Systematic Reviews, Issue 1. 2007.
• Wickham R. Chemotherapy-Induced Peripheral Neuropathy: A Review and Implications for Oncology Nursing Practice. Clinical Journal of Oncology Nursing, Volume 11(3)361-376. 2007.

For further references, please see the general bibliography.