The National Cancer Institute (NCI) defines neuropathy as a problem in peripheral nerve function (any part of the nervous system except the brain and spinal cord) that causes pain, numbness, tingling, swelling and muscle weakness in various parts of the body.

For cancer patients, neuropathy is usually triggered by chemotherapy medications — but it can be caused by or made worse by other conditions and factors, such as diabetes, kidney failure, alcoholism and malnutrition, and by injuries, exposure to toxic chemicals and infection. The hands and feet are the body parts most often affected by chemotherapy-related neuropathy. In some people, the cancer itself may contribute to neuropathy.

Not all chemotherapy drugs cause neuropathy. NCI lists these as most likely to do so:

• Cisplatinum (Platinol)
• Carboplatin (Paraplatin)
• Vincristine (Oncovin)
• Vinblastine (Velban)
• Etoposide/VP-16 (VePesid)
• Cytarabine (Cytosar, Ara-C)
• Hexamethylmelamine (Hexalen)
• Suramin
• Paclitaxel (Taxol) and Docetaxel (Taxotere)

Other medications reported to contribute to neuropathy include oxaliplatin (Eloxatin), gemcitibine (Gemzar) and thalidomide (Thalomid).

Neuropathy, when it does occur, varies widely in severity, symptoms, and duration, from person to person. Factors that may influence the development of neuropathy include a patient's:

• Age
• Liver and kidney function
• Existing nerve conditions, such as prior never damage like carpal tunnel syndrome, pinched nerves, prior neuropathy from diabetes or the underlying diseases of myeloma or thyroid problems
• Frequency of chemotherapy
• Types and doses of chemotherapy (higher doses increase the chance of developing neuropathy)
• Other medications taken for other conditions which interact with chemotherapy medication
• Certain vitamin deficiencies or nutritional deficiencies present before chemotherapy is started

Hearing that one cancer patient has a severe neuropathy should not automatically lead you to believe that you, too, will have this experience. Some people develop a relatively minor amount of neuropathy, and it never progresses much beyond the initial level. It's important to understand that having some neuropathy doesn't always mean that it will develop into a serious problem.

Symptoms

Symptoms, like severity, vary from person to person. Most people feel initial symptoms in the hands and feet, beginning with the finger tips and toes. In many people, the tingling and pain may move up from the fingers to the hands, from the toes to the feet, in what is called a "stocking-glove" pattern, mimicking how a person puts on gloves and stockings.

The most common symptoms patients report are these:

• Tingling — a feeling of needles and pins, and burning
• Sudden, sharp "stabbing" or "electric shock" pain sensations
• Loss of sensation of touch
• Loss of balance, difficulty walking
• Clumsiness
• Difficulty picking up objects, buttoning clothing
• Hearing loss
• Jaw pain
• Constipation
• Oversensitivity, or decreased sensitivity, to heat and cold

Symptoms can begin after your first dose of chemotherapy, or after later treatments. Once you begin to feel symptoms, tell your health care team. It is important to diagnose neuropathy promptly and take steps to ease the problem.

Testing for the presence and degree of neuropathy usually involves testing your reflexes and using a pin or cotton on your hands and feet to see how quickly you detect sensation there. If needed, another test is an electromyelogram (EMG), which will record electrical impulses from nerves. An additional test that may be used is the nerve conduction test (NCT). Both of the latter tests are uncomfortable because they involve needles in your muscles or nerves.

Prevention

There is no sound clinical evidence of any medication that can be taken to always prevent the onset of neuropathy — but there are steps you can take to minimize discomfort, maximize your stability and prevent injury as you cope with this side effect:

• Really pay attention when you walk, if your toes/feet are affected — far more attention than you might have paid before neuropathy. This can help you avoid falls.
  
  
• If your hands are affected, be especially careful handling sharp objects like knives and razors; consider using an electric razor if need be.
  
  
• Consider having manicures if your hands are painful — but don't let the manicurist cut your cuticles, as this can invite infections.
  
  
• Special attention should be paid to your feet if your neuropathy means you cannot feel small cuts — from nail trimming — on your toes. Have a pedicure or see a podiatrist for foot care.
  
  
• Footwear should be low-heeled, comfortable and sturdy.
  
  
• Avoid extreme temperatures of heat and cold; extremes can cause increased pain in some people.

Additionally, the medication amifostine (Ethyol) can be given to some patients before chemotherapy is administered, and is reported to protect the body's tissues from neuropathy — without reducing the effectiveness of the chemotherapy medications in any way. This approach to prevention is most commonly done for patients taking chemo medications that are most likely to cause neuropathy. However, amifostine can cause abrupt drops in blood pressure, so special techniques of administration are necessary, including having the patient lie down when the medication and chemotherapy are given. Also, if you take medications for blood pressure, they probably should not be taken when amifostine is used. Discuss the use of amifostine and the precautions to be taken with your health care team.

Treatment

Treatment of neuropathy often requires patience — on the parts of both the person with cancer and the health care team. More than many side effects, effective treatment here may take time to find.

Special note: check with your physician to see if you may have deficiencies in vitamin B-12, folate or magnesium. Also, have your thyroid function checked.

Medications are a front-line offense against the pain caused by neuropathy, and there are several different categories of medicine used:

1. Tricyclic antidepressants and anticonvulsants (see below) are usually the standard initial therapy, with evidence showing that a majority of patients suffering from neuropathy find some relief from these medications. If tricyclics are right for you, and if your most prominent symptom is tingling, burning pain, your health care team will select medications from this category depending on your symptoms and description of your pain. Usually, tricyclic antidepressants are started at a low dose, gradually increasing until some relief is obtained. If one of these medications isn't successful, your health care team may try others in this same category before trying another approach; just because one doesn't work does not mean another antidepressant will not.
   
   It's very important to understand that the use of antidepressants does not mean that your neuropathic pain is imagined, or that you are depressed. Many medications, including antidepressants, are effective treatment for conditions other than the one for which they were created.
   
   Some commonly prescribed antidepressants are:
   
   
   • Amitriptyline (Elavil)
   • Desipramine (Norpramin)
   • Nortriptyline (Pamelor)
   
   
2. Anticonvulsants are also effective for certain kinds of neuropathic pain, especially the sharp, stabbing pains. The medications in this category include
   
   
   • Carbamazepine (Tegretol)
   • Gabapentin (Neurotin)
   
   
3. Topical creams are to be rubbed on the exterior of painful part of the body, and have proven effective for some neuropathy. The most commonly used of these preparations is capsaicin (Zostrix) — a cream made of chili pepper extract. Capsaicin cream may produce a burning sensation on the skin when first used, but that feeling passes with continued use. Wash your hands immediately after each use, and be especially careful to avoid getting any in your eyes.
   
   
4. Opioids can help some people with neuropathy, and is usually a next step if tricyclic antidepressants and anticonvulsants aren't working well. Opioids can also be given in combinations with antidepressants or anticonvulsants.
   
   
5. Lidocaine patches (Lidoderm) have a numbing effect and are sometimes helpful for pain control.

There are other medications that can be tried if those listed above prove ineffective. Recent research has shown, in a small clinical trial, that some patients benefit from having intravenous magnesium added to their hydration during chemotherapy. [Journal of Pain and Symptom Management, Jan. 2000; 19: 35-39.] Since chemotherapy often decreases the magnesium levels in patients, replenishing of that mineral may be effective. More research is needed before this approach is validated. Discuss this with your health care team.

Non-Medication Approaches can also be very helpful for neuropathic pain. Here are some approaches recommended by health care providers and cancer patients that have been effective for some people:

• Some people find relief from acupuncture and/or acupressure. Talk with your health care team about these.
  
  
• Physical therapy can prove helpful for some. A physical therapist knowledgeable about treating neuropathy can show you exercises that can help.
  
  
• Exercise — especially swimming and walking — have proven helpful to some people.
  
  
• Occupational therapy can be useful to you if you're having trouble with some of life's daily functions, such as buttoning clothing, cooking and writing.
  
  
• Application of warm heat or cold packs have proven helpful to some people.
  
  
• Patients have reported informally that physicians have suggested that they take supplements, such as Vitamin B-100 (vitamin B1, riboflavin, niacin, vitamin B6, folic acid, vitamin B12, biotin, pantothenic acid, choline and inosital). Others report help from taking glutamine when taking taxane chemotherapies (Taxol, Taxotere). Talk with your health care team before doing this.
  

Questions for Your Doctor

In treating neuropathy, your health care team may include an oncologist, pain management expert, physical therapist, nurse and occupational therapist.

1. Are the chemotherapy medications I am taking likely to cause neuropathy?
   
   
2. Am I at special risk for neuropathy?
   
   
3. How will you test me to see if I have neuropathy?
   
   
4. How have you managed neuropathy in other patients? With what results?
   
   
5. What resources and options are available to help me deal with neuropathy? Are there experts in pain management, physical and occupational therapy available to help?
   
   
6. What medications will you consider treating me with if my neuropathy is painful?
   
   
7. Are there other techniques that don't involve medications that can help? When might I begin trying these?
   
   
8. Is it likely that my neuropathy will improve or go away entirely once treatment is over?
   
   
9. If my neuropathy is very painful and extensive, will this have an impact on my treatment plan?
   

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