New developments in managing chemotherapy-induced neuropathy

Chemotherapy is a proven and effective method for treating many types of cancer, but up to 90% of patients who receive the treatment develop chemotherapy-induced peripheral neuropathy, also known as CIPN. The condition occurs when the same toxic ingredients in chemotherapy drugs that kill cancer cells also damage the nerves in the hands and feet.

Survivors are left with numbness, tingling or loss of feeling in their extremities. They may have difficulty buttoning shirts, zipping pants, picking up drinks and opening jars, and some may suffer debilitating pain. In some cases, neuropathy in the feet becomes so pronounced that patients can no longer drive because they cannot feel the pressure they are putting on the pedals. Others lose their sense of balance and require the use of a walker.

Most cases are treated with a combination of antidepressants, anticonvulsants, and analgesics. Topical numbing agents such as lidocaine are sometimes used, and opioids may be prescribed in cases involving extreme pain. However, none of these options are especially effective, and all have adverse effects.

“Neuropathy is a pretty pervasive problem; it can happen to patients with any type of cancer and be caused by many types of chemotherapy,” said Sarah Prinsloo, Ph.D., assistant professor of Palliative, Rehabilitation, and Integrative Medicine. “And there aren’t a lot of effective treatments on the market for it.”

Prinsloo and others are working to change this by testing new, non-pharmaceutical treatments to control, and perhaps even reverse, CIPN.

Trials underway at MD Anderson include:

• Neurofeedback, a type of biofeedback in which electroencephalography (EEG) sensors are placed on the patient’s scalp to track the brain waves in the regions that are active during neuropathy pain episodes. By watching their brain wave patterns on a video monitor, patients learn to alter their wave patterns and “reset” the brain to self-correct during pain episodes.
• Scrambler therapy, which uses a machine to block the transmission of pain signals by providing non-pain information to nerve fibers that have been receiving pain messages.
• Repetitive transcranial magnetic stimulation, also called rTMS, uses magnetic fields to generate electrical currents that alter pain processing in the brain.

Even as new pain therapies move forward, questions about neuropathy remain.

“We need to understand much more about how neuropathy normally resolves. A significant portion of patients with neuropathy continue to have the problem after they complete chemotherapy, but there’s also a large group whose pain goes away when treatment stops,” says Annemieke Kavelaars, Ph.D., professor of Symptom Research. “And we don’t know why some people continue to have the problem and others don’t.”

Finding answers to these questions, Kavelaars hopes, will help researchers develop even more effective therapies for CIPN.

“After years of frustration, we’re finally moving toward finding interventions that can truly resolve CIPN,” she says. “There’s real relief for these patients on the horizon.”