Peripheral Neuropathy: Exercise May Help, Study Finds

Though chemotherapy is a powerful tool against cancer, it can cause serious and painful side effects, including a type of nerve damage called chemotherapy-induced peripheral neuropathy (CIPN). If you are undergoing chemotherapy, before you develop CIPN, you may want to consider doing physical activities focusing on nerve-muscle communication – namely sensorimotor training or whole-body vibration training. These exercise interventions have been found to reduce the incidence of CIPN compared with treatment as usual, according to results from the STOP trial published July 1 in JAMA Internal Medicine.

The study “adds to the burgeoning evidence about the benefits of exercise and physical medicine interventions in patients at risk of or with neuropathy” wrote the authors of an invited commentary on the paper published in the same issue.

The Study Rationale

Peripheral neuropathy, or tingling and numbness in the hands and feet, is a common and sometimes debilitating side effect of chemotherapy. Although one drug exists to alleviate neuropathic pain, there are no treatments for neuropathy itself. Nor do American Society of Clinical Oncology (ASCO) guidelines recommend any intervention to prevent CIPN outside the context of a clinical trial like this one.

The STOP trial explored two exercise interventions to prevent CIPN:

• The first, sensorimotor training, is essentially balance exercises performed on one or two feet on increasingly unstable surfaces.

• Whole-body vibration training involves standing or lying on a programmable, vibrating platform.

As for when you should start these interventions, study author Fiona Streckmann, PhD, a research associate at the University of Basel, in Switzerland, told Patient Power that she believes patients should try to maintain their nerve-muscle communication during cancer treatment, rather than letting it decline and then trying to fix it later. Sensorimotor training, she said, is the way to do that maintenance.

The Study Design

In the STOP trial, which recruited participants from four medical centers in Germany, study participants who were slated to receive oxaliplatin or vinca alkaloid chemotherapy were randomly assigned to:

• One of two exercise interventions, sensorimotor training (SMT) or whole-body vibration (WVB) training, or

• A control group, which had no exercise intervention.

The researchers selected those chemotherapies because they come with the highest risk of CIPN, Dr. Streckmann said. Accordingly, study participants had cancers that are typically treated using oxaliplatin and vinca alkaloids — primary lymphomas and colorectal cancers.

Participants had exercise sessions twice weekly for 10-20 minutes per session during the same period that they were received chemotherapy, typically three months. The researchers assessed study participants for CIPN before and after their chemotherapy treatment, and again three months after the end of chemo.

The researchers determined CIPN incidence using a battery of neurological tests examining reflexes, vibration sensitivity, and ability to sense the positions of one’s toes, among other tests. Researchers followed participants’ treatment outcomes for up to five years.

What the Study Found

The incidence of peripheral neuropathy was lower in the intervention groups than in the control group. In the control group, about 71% of participants developed peripheral neuropathy, compared with 30% in the sensorimotor training group and 41% in the whole-body vibration training group.

“This adds to an enlarging list showing that there is a potential to reduce or prevent the onset of CIPN or even just chemotherapy-induced neuropathy, CIN, with exercise interventions,” said Tom Smith, MD, a medical oncologist and Director of Palliative Medicine at Johns Hopkins Medical Institutions, who was not involved in the study.

Were All Types of Chemotherapy Drugs Studied?

“There are a couple of real provisos for this study to be applicable to most cancer patients. Number one is no one got a taxane,” Dr. Smith said. Taxanes, which are chemotherapy drugs which stop cells from replicating, are used to treat some of the most common cancers, such as breast and lung cancer.

Because the study only included certain chemotherapies, the results are not generalizable to patients receiving other chemotherapies for other cancer types, Dr. Smith said.

Dr. Streckmann said that the researchers examined oxaliplatin and vinca alkaloid chemotherapies because they cause the most CIPN. Had they examined a chemotherapy that caused less frequent neuropathy, such as taxanes, they would have had to recruit even more patients, she noted.

Why Were Some Participants Excluded?

Another criticism of the study is that the researchers screened 1605 people for study eligibility, but slightly less than 10% of those ended up participating. The fact that so many potential participants were ultimately excluded could “limit generalizability” of the interventions, wrote the authors of the invited commentary.

The most common reason that screened patients were excluded from the study was a change in a patient’s planned chemotherapy regimen to something other than oxaliplatin or vinca alkaloids. The researchers had to recruit participants so early in the diagnosis process that sometimes, it turned out a potential participant had a different type of cancer requiring a different chemotherapy by the time the study began, Dr. Streckmann said.

But some people were excluded because they had contraindications for the training. Some lived too far away to participate. Those factors could potentially affect people’s adoption of an exercise intervention in the real world.

“When you even start to try to implement this, will patients do it? And if they would, how do you scale it?” asked Bryan Schneider, MD, the Vera Bradley Chair of Oncology at the Indiana University Melvin and Bren Simon Cancer Center, in Indianapolis, who was not involved in the study.

Dr. Smith wished that the study had reported more directly on the effect of the exercises on neuropathy’s hallmark symptoms of pain, numbness, and tingling. Instead, the study’s primary endpoint was the incidence of CIPN as measured by the results of the neurological test battery.

The researchers did assess and report on pain, numbness, and tingling – but as secondary endpoints. In the intention-to-treat population (which included everyone who received any exercise interventions) none of the secondary endpoints, including those three, were statistically different between the intervention and control groups.

What Action Steps Can I Take?

Dr. Streckmann and colleagues plan to create an app that will guide patients through sensorimotor training exercises. People can sign up to receive updates about the app at this link.

Meanwhile, patients interested in sensorimotor training can seek out balance exercises on their own or with a trainer or physical therapist, Dr. Streckmann said. Whole-body vibration training, on the other hand, requires supervision and is not something that patients should try to do on their own, she added.