What is Peripheral Neuropathy

Neuropathy

Peripheral neuropathy is caused by damage to your peripheral nerves. Peripheral nerves are nerves that are not located in the brain or spinal cord. They are found throughout your body and help you feel things. They also control the function of your organs. The damage is usually to nerves in the hands, feet, arms, and legs.

Cancer treatments are meant to kill cancer cells. A side-effect is that normal cells can also be damaged or killed. When chemotherapy damages peripheral nerves, it is called chemotherapy-induced peripheral neuropathy, or CIPN. Other types of cancer treatments can also cause peripheral neuropathy.

What Cancer Treatments Cause Peripheral Neuropathy?

Drugs for cancer treatment are the most common cause of peripheral neuropathy. But peripheral neuropathy can be also caused by surgery, radiation, the tumor pressing directly on nerves, chemicals released by tumors, and infections.

Peripheral neuropathy can be a side effect of these drugs:

  • Platinum drugs, such as cisplatin (Platinol), oxaliplatin (Eloxatin), carboplatin (Paraplatin)
  • Taxanes, such as paclitaxel (Taxol, Abraxane), docetaxel (Taxotere)
  • Vinca alkaloids, such as vincristine (Oncovin, Vincasar), vinorelbine (Navelbine), and vinblastine (Velban)
  • Podophyllotoxins, such as etoposide (Etopophos, VePesid, Toposar, VP-16) and teniposide (Vumon)
  • Epothilones, such as ixabepilone (Ixempra)
  • Thalidomide (Thalomid) and lenalidomide (Revlimid)
  • Bortezomib (Velcade)
  • Interferon
  • Methotrexate (Rheumatrex, Trexall, Amethopterin, MTX)
  • Fluorouracil (5-FU, Adrucil)
  • Cytarabine (Cytosar-U)

What are the symptoms of peripheral neuropathy?

There are three types of peripheral nerves: sensory, motor, and autonomic. If damage occurs to sensory nerves, you may feel pain, tingling, or numbness. If the damage is mainly to the motor nerves, you may feel weak or off-balance. If the damage is to the autonomic nerves (which control organ function) you may have constipation or dizziness.

Symptoms tend to start in the fingers and toes, progressing to hands and feet, then arms and legs. It can become hard to pick things up, hold on to things, walk, and perform tasks like buttoning your shirt.

Symptoms can begin any time after your treatment begins. They may start suddenly. Symptoms are usually mild at the beginning and slowly worsen. Symptoms also get better slowly, usually over the course of a few months. Unfortunately, sometimes the damage is permanent and symptoms do not go away.

Common symptoms are

  • Tingling
  • Numbness
  • Weakness
  • Cramping
  • Burning
  • Pain (may be there all the time or may come and go, like shooting or stabbing pain)
  • Not being able to feel things that are touched
  • Not being able to sense cold or heat
  • Sensitivity to cold or heat or touch
  • Feeling off balance
  • Dizziness
  • Having trouble walking
  • Constipation

Tell your doctor as soon as possible if you experience any of these symptoms.

Who is at Increased Risk for Peripheral Neuropathy?

Thirty percent to 40 percent of patients treated with chemotherapy develop some degree of peripheral neuropathy. Doctors cannot predict who will develop peripheral neuropathy, but some things make you more likely to develop it:

  • Having had chemotherapy, radiation, or surgery before
  • Needing a high dose or long course of treatment
  • Taking more than 1 drug that can cause neuropathy
  • Having a history of alcohol abuse
  • Being a diabetic
  • Having HIV or AIDS
  • Having severe malnutrition
  • Having multiple myeloma, lymphoma, or lung or breast cancer
  • Having nerve damage from previous injury or illness

How is Peripheral Neuropathy Diagnosed?

Tell your doctor if you think that you have peripheral neuropathy. Your doctor may watch you walk and test your reflexes, strength, and ability to feel touch. The doctor may also perform nerve conduction tests, which measure the strength and speed of electrical signals sent by your nerves in response to small shocks.

Can Peripheral Neuropathy be Prevented?

There is no proven way to prevent nerve damage in patients undergoing treatment. It probably helps to give less of the cancer drug. "Stop and go" schedules are also being tested to see if a pre-planned break in treatment prevents neuropathy without reducing the effectiveness of the cancer treatment.

Many drugs and supplements are being tested to prevent peripheral neuropathy in patients with cancer. Results have been mixed. More research is needed. Some prevention treatments being tested are:

  • Calcium and magnesium infusion
  • Glutathione
  • Acetyl-L-carnitine
  • Alpha-lipoic acid
  • Acetylcysteine
  • Glutamine
  • Amifostine (Ethyol)
  • Xaliproden
  • Org 2766
  • Carbamazepine
  • Vitamin E
  • Vitamins B1 and B12

Check with your doctor before taking any supplements. They can make your cancer treatments work less well and might cause problematic side effects, especially if taken at the wrong dose.

If you develop neuropathy symptoms during treatment, your treatment might be stopped. Your treatment can be restarted after you feel better or if the tumor starts to grow again. This treatment break can prevent the nerve damage from getting worse. Without it, your symptoms might worsen and become permanent.

How is Peripheral Neuropathy Treated?

There are no treatments for peripheral neuropathy that fix the nerve damage. Instead, treatment is given to relieve and manage symptoms. And unfortunately, many of the treatments are not proven to help and have side effects of their own. Many patients do find relief, however, with combinations of drugs, dietary supplements, and other types of therapy.

Some of the same drugs and supplements being studied for prevention are also used for treatment.

Your doctor may prescribe drugs to help manage the symptoms of peripheral neuropathy, such as:

  • An antidepressant (ex, duloxetine, venlafaxine, amitriptyline) for tingling and numbness
  • An anticonvulsant (ex, phenytoin, carbamazepine) for pain
  • A muscle-relaxant (ex, baclofen)
  • An analgesic (ex, ketamine)
  • A steroid for short-term use
  • Lidocaine patches
  • Capsaicin cream (made from chili pepper extract)
  • Opioids or narcotics for severe pain
  • A gentle laxative for constipation

Your doctor may recommend some dietary supplements, such as:

  • A combination B vitamin
  • Folic acid
  • Magnesium
  • Glutamine

There are other treatments that may help you manage your symptoms, including:

  • Transcutaneous nerve stimulation (TENS, in which nerves are stimulated to release endorphins with a gentle electrical current)
  • Occupational and/or physical therapy
  • Massage
  • Exercise
  • Guided imagery, meditation, relaxation, and distraction techniques
  • Biofeedback
  • Acupuncture

What Else can I Do?

When you cannot feel your hands and feet, you are at risk for injuries. Also, injuries can go unnoticed and become infected. You must be careful to protect yourself. Here are some things you can do:

  • Wear good footwear to protect your feet from injury
  • Wear gloves when using your hands to protect them from injury
  • Inspect your skin for injuries at least once each day
  • Be extra careful when handling sharp objects or hot liquids
  • Be extra careful on stairs; use the handrail
  • Use non-skid surfaces in the bath and other slippery spots
  • Set your hot water heater to 120°F or lower to prevent burns
  • Use a cane or other device if you have trouble with balance
  • Ask for help

In addition, avoid alcohol because it can make symptoms worse. Keep the temperature in your home at a comfortable level because extreme hot or cold can make symptoms worse.

Finally, be sure to get the emotional support you need. You may find a support group near you at www.neuropathy.org. You can also ask your doctor for a referral to a mental health professional.

Questions for Your Doctor

  • Can the cancer treatments you are suggesting cause neuropathy?
  • What symptoms should I look for?
  • Are there different, safer treatments or treatment schedules we can use?
  • Would these different treatments or schedules affect my chances for a cure?
  • Are there any clinical trials in which I can participate for prevention of neuropathy?
  • What can I do to manage my symptoms? Are there any clinical trials in which I can participate for treatment of neuropathy?
  • What local resources can help me deal with my symptoms?