Nursing Neuropathy
Dealing with a sometimes painful pins-and-needles side effect of cancer treatment.

By Debra Wood, RN

While grateful that a bone marrow transplant saved his life and eliminated all the leukemia cells, Bart Dunn copes daily with severe nerve pain that has been a constant companion for the 11 years the Charlotte, North Carolina, man has been cancer-free.

“With pain, you have two choices: give up and let the pain control you or deal with it,” says Dunn, 47. “I still have a good life and do things I enjoy. ”

With a case more severe than most, Dunn suffers from neuropathy, a fairly common side effect of some chemotherapy agents. Neuropathy refers to an injury to the peripheral nerves, which are made up of sensory nerves (needed for touch, temperature and pain) and motor nerves (aid in movement and muscle tone).

Sensory neuropathy is more common than motor neuropathy and may result in pain as well as numbness and a tingling or loss of sensation. Motor nerve damage results in a disruption of signals to the muscles and can result in symptoms such as muscle weakness, problems with balance and foot drop.
For cancer patients, the legs, feet, arms and hands are most commonly affected. The feet almost always come first.

The How and Why

Radiation therapy to the spine or other tissues can cause neuropathy by radiating the nerves. In addition, the cancer itself can cause nerve damage, especially if the tumor is close to a particular nerve. But the most common cause of nerve damage is chemotherapy.

A number of chemotherapy drugs, including Platinol® (cisplatin), Taxol® (paclitaxel), Taxotere® (docetaxel), Oncovin® (vincristine) and Navelbine® (vinorelbine) frequently prove toxic to nerves. Velcade® (bortezomib) and Thalomid® (thalidomide), both used to treat multiple myeloma, are newer drugs that also can cause neuropathy.

Once nerve tissue is damaged it has limited capacity to reproduce and regenerate. The body of the nerve cell (neuron) usually cannot repair itself, while the peripheral axons, the nerve fibers that branch off the body of the nerve cell, may have the ability to heal with time.

“Chemotherapy-related neuropathy has to do with injury occurring in long, peripheral nerves,” says Marc C. Chamberlain, MD, professor of neurology and co-director of the neuro-oncology program at the University of Southern California Keck School of Medicine in Los Angeles. Some of these nerves are several feet long, running all the way from the spine to the toes (see illustration).

Signs and Symptoms

Mary Andersen developed neuropathy in her feet and fingers about five months after she began receiving Taxol and carboplatin for treatment of lung cancer.
“My fingers are not as bad as my toes,” says the Ocean City, New Jersey, resident. “If I stand on my feet too long, it bothers me. But when I go to the supermarket, I hold on to the basket and I do just fine. I’m not in pain—I’m just an old lady!”

Neuropathy may occur weeks or months after treatment ends, but patients receiving vinca alkaloids may also develop neuropathy during treatment. And for some radiation patients, nerve damage may not become apparent until years after treatment.

As damage develops, the nerves die back in length, causing numbness, tingling, burning sensations or pain, especially in the tips of fingers and toes. Some sufferers may not be able to sense the position of their feet, making it difficult to walk. Others cannot feel vibration.

“They also have difficulty with fine-motor activities, such as buttoning a shirt or blouse, picking up smaller objects with their fingers or other activities that require accurate sensation of touch,” says Jan Perun, ARNP, AOCN, a medical oncology nurse practitioner at M. D. Anderson Cancer Center in Orlando.

As with many cases of cancer-related neuropathy, Dunn’s symptoms began in his feet and hands and gradually progressed. Chemotherapy-induced neuropathy typically develops symmetrically and bilaterally. “My whole body feels like I have a severe sunburn,” says Dunn. Even light touch or air movement magnifies the discomfort.

Patients more commonly experience a pins-and-needles sensation. Many patients receiving Eloxatin® (oxaliplatin), used to treat colon cancer, develop a cold-sensitive neuropathy within the first few days of treatment. This may be related to the drug binding with calcium, causing a hyperactive state in the nerves.

“If the patient touches something cold, they experience a burning or electrical sensation,” says Michael Morse, MD, associate professor of medicine at Duke University Medical Center. “If they try to drink something cold, they get discomfort in the lips, tongue and throat. Some people get jaw spasms.”

Eloxatin-induced cold neuropathies often resolve within a couple of weeks of completing treatment and do not become permanent. However, patients receiving Eloxatin may develop a chronic neuropathy, which may or may not resolve over time.

Neuronopathy, injury to the body of the nerve cell, is another type of chemotherapy-related neuropathy. The cell body is located adjacent to the spinal cord and can be damaged by a number of chemotherapeutic agents.

Who’s At Risk

Patients with nerves damaged by an inherited disorder, diabetes, excessive alcohol use or another condition may be predisposed to developing chemotherapy-induced neuropathies. Charcot-Marie-Tooth (CMT), an example of a hereditary disorder associated with neuropathy, affects about one in 2,500 people with symptoms that can include weakness, absent reflexes and sensory loss. Milder versions of CMT may be inherited by as many as 1 to 5 percent of all patients. Because of their inherited predisposition to nerve damage, these individuals are especially susceptible to chemotherapy-induced neuropathy.

Nerves already diseased due to a medical condition may be more susceptible to injury when exposed to cancer drugs. In the case of diabetes, a high blood sugar level is thought to weaken the ability of nerves to transmit signals, so it is recommended that patients work with their doctor to keep levels as normal as possible.

For some patients, a pre-existing condition may be unknown. Dr. Chamberlain points out that the underlying nerve damage may not produce symptoms until the patient is exposed to the cancer-killing agent.

Managing Neuropathy

Neuropathy may limit the amount of chemotherapy a patient can receive and affect treatment success. With most agents, the chance of developing neuropathy increases with each additional exposure to the drug.

Bone marrow (stem cell) transplant patients, such as Dunn, receive much higher doses of drugs than normally given. With traditional chemotherapy, oncologists aim to administer a high enough dose to kill the cancer but often will cut back as soon as nerve symptoms develop. Patients should alert the doctor at the first sign of problems.

“The neuropathy is, hopefully, recognized at a point when a dose modification or discontinuance can prevent further progression,” Dr. Chamberlain says.

Symptoms may persist or even worsen after stopping the drug, a phenomenon referred to as “coasting.” Gradually, over a period of time, the symptoms may resolve as the nerves slowly heal.

“If the drug is discontinued early enough and the progression is modest beyond that, the patient often makes an almost complete and full recovery,” Dr. Chamberlain says. “In the majority of patients, we recognize the neuropathy early enough that we prevent profound functional disability.”

Researchers are investigating giving compounds to protect the nerve, but these are not yet available in clinical practice. One promising pretreatment drug currently being studied in clinical trials is amifostine, which has been shown to reduce both the incidence and intensity of neuropathy caused by cisplatin chemotherapy.

With Eloxatin, physicians have met with some success in reducing the incidence and intensity of neuropathy symptoms by giving calcium and magnesium infusions prior to the chemotherapy agent. The infusion supplements the calcium in the blood, decreasing the risk of a hyperactive state in the nerves. The magnesium may help maintain adequate calcium levels.

Treatment options for people who develop chronic neuropathies are limited and aim to manage painful symptoms. Dr. Chamberlain says there is no treatment for the more common problem of numbness and tingling.

Drugs for symptoms may include anticonvulsants, such as Neurontin® (gabapentin), and antidepressants, including nortriptyline or amitriptyline, which are often prescribed “off-label.” The U.S. Food and Drug Administration has not approved these drugs for treating neuropathy, but in practice, physicians have found they often bring patients some relief.

Tricyclic antidepressants relieve neuropathy by decreasing the chemicals in the brain that transmit pain signals. These drugs are often ordered at bedtime because they may produce a sedative effect. Older adults may receive lower doses to decrease potential adverse reactions.

Patients generally take Neurontin three times daily. Common side effects include dizziness, sleepiness and weight gain. Doctors typically start patients off on a low dose and can increase the amount of medication as needed to ease the pain.

With a physician’s order, a compounding pharmacy can prepare a topical cream containing the active ingredient in Neurontin for application to the skin, administration that produces fewer side effects.

Also available topically is lidocaine patch (Lidoderm®). Lidoderm is applied to intact skin in the area with the most pain.

At first, Dunn’s physicians thought he might have fibromyalgia and tried different types of pain medication without success. Dunn eventually traveled to the Mayo Clinic in Jacksonville, Florida, for a complete evaluation. After finding severe, permanent nerve damage, the consultants convinced Dunn’s regular oncologist to prescribe OxyContin® (oxycodone [not typically given, as it is habit-forming]), an extended-release narcotic medication, in addition to Neurontin.
“Together they make things manageable, but barely,” Dunn says.

Drug-Free Methods

Used alone or in conjunction with medication are a number of therapies that can include acupuncture (see sidebar, page 61), massage and herbs. Physical therapy may strengthen weakened muscles, and an occupational therapist may recommend assistive devices that help with daily activities. Perun has found lotions and udder cream can be soothing when applied to the hands and feet.

Another option is transcutaneous electrical nerve stimulation (TENS), which helps prevent pain signals from reaching the brain by delivering painless electrical impulses through electrodes positioned on the skin. TENS doesn’t work for all types of pain and is generally less effective for chronic pain as opposed to acute pain.

But whether a patient suffers from mild or severe neuropathy, there are ways to go about improving safety (see sidebar) and quality of life. Dunn cut back his hours on the job and tries to eliminate stressful events—good and bad, physical and emotional—which increase the pain. He limits physical activity and attempts to keep life on an even keel. He sleeps with an ice bag on his feet, which cools the burning sensation.

“It is also important to protect areas of decreased sensation,” Perun says. “For example, wear thick socks and thick-soled shoes, avoid extreme temperature changes, wear warm clothing in the winter, protect your feet and hands from extreme cold, use gloves when working in the garden and use potholders when cooking. ”

Andersen uses a cane when she has difficulty walking and credits a foot massager with helping relieve the discomfort. As for Dunn, he remains hopeful and willing to try other therapies to treat the permanent damage to his nerves.
“I try to live life and not overreact,” Dunn says. “I don’t give up. I keep going and do the best I can. ”

—Melissa Weber contributed to this article.