Peripheral Neuropathy & Chemotherapy

If you’ve ever had a charley horse — or a severe sudden spasm in your calf — you know that muscle cramps are no joke.  

But did you also know that muscle cramps can be a side effect of cancer treatment? Below, I’ll explain why these uncomfortable spasms sometimes happen to cancer patients, how we treat them, and whether they’re temporary or permanent. 

Why do muscle cramps occur in cancer patients?

There are many possible causes. 

Chemotherapy

Several classes of chemotherapy can cause muscle cramps. These include:  

• platinum-based drugs (cisplatin)  
• vinca-alkaloid drugs (vincristine and vinblastine)  

But cramps can also be a side effect of some hormonal therapies, including the aromatase inhibitors used to treat breast cancer. All of these can damage the roots of our nerves, which may lead to muscle cramps and neuropathy. 

Electrolyte imbalances

A lot of chemotherapy drugs make patients dehydrated, which can result in electrolyte imbalances. If your potassium, magnesium or calcium levels get out of whack, that can lead to muscle cramps. Other causes of electrolyte imbalances include diuretics (fluid pills), kidney dysfunction and kidney failure.  

Anti-fungal medication

Amphotericin-B is a very potent antifungal medication used to treat opportunistic infections in neutropenic patients. It is also known to cause muscle cramps as a side effect. 

Lithium

This drug is used to treat bipolar disorders, but if you get too much or too little of it, you start seeing side effects very quickly. 

Hypothyroidism

Patients undergoing immunotherapy sometimes have this condition due to their treatment. 

Polymyositis

This is a rheumatological disorder associated with an increased risk of having cancer. Muscle cramps are an active symptom of the disease. 

Metastatic disease 

Some patients experience muscle cramps because they have metastatic cancer that has spread to the central nervous system and is now pressing on their nerves. This includes leptomeningeal disease, in which cancer spreads to the fluid surrounding the brain and spinal cord and/or the leptomeninges, the lining of the brain and spinal cord.  

Diabetes

This condition can sometimes cause muscle cramps. 

Anemia 

Red blood cells carry oxygen to the muscles. When there are not enough of them to do that job effectively, and your blood oxygen level drops, the result can be muscle cramps. 

Do muscle cramps only occur in certain locations?

No. It depends on what’s causing them. People can get them in their arms, legs, abdomen or other areas.  

How are muscle cramps typically treated? 

Again, it depends on the source. Here are a few things we suggest or prescribe: 

• exercise 
• oral and/or IV supplements 
• stretching 
• heating pads 
• muscle relaxers 

Are muscle cramps ever permanent? 

Some cancer survivors experience side effects for years after finishing treatment. But if we can identify the underlying source of your muscle cramps — such as an electrolyte imbalance or a thyroid problem — they typically get better as soon as we fix it. The cramps might not go away completely, but they definitely improve. 

Lucy Potter, M.D., is an internist in the Internal Medicine Center with a special interest in cancer-related fatigue. 

Request an appointment at MD Anderson online or call 1-877-632-6789.

Peripheral neuropathy is nerve damage that occurs outside of your brain and spinal cord. It can cause weakness, numbness and pain — most commonly in your hands and feet.

It’s a relatively common side effect of diabetes, but it also can be caused by physical injuries, exposure to some toxins, infections and as a side effect of chemotherapy.

Peripheral neuropathy is typically treated by managing the underlying cause through medications, using walking aids and nerve stimulation procedures.

But could red light therapy also treat peripheral neuropathy? As a pain medicine specialist, I study the effectiveness of red light therapy on peripheral neuropathy caused by cancer treatment. And the results I’ve seen are promising.

Read on to learn more about this treatment option, its benefits and risks, as well as how to try it.

What does red light therapy do for peripheral neuropathy?

Red light therapy, also called photobiomodulation or low-level light therapy, uses specific wavelengths of near-infrared light from wands, panels, pods or other devices to stimulate activity at the cellular level and promote healing.

When red light enters your skin, your mitochondria (the tiny structures inside your cells that act as the "power plants" of your body) use it to create energy needed to help cells repair themselves.

Depending on the frequencies, some of them penetrate a little bit deeper than skin, reaching the muscles, nerves and even bones. It also promotes the release of nitric oxide and causes vasodilation, the widening of blood vessels, which improves blood flow.

This treatment is known to reduce inflammation, which also aids in circulation.

All these mechanisms combined stimulate nerve repair and regeneration.

Red light therapy is available as in-office treatment using a combination of LEDs and lasers, or as a home treatment using less-powerful LED devices.

It was first used as a treatment for aging skin. More recently, it has been used as a supplementary treatment aimed at reducing pain and inflammation‚ including from peripheral neuropathy.

In-office vs. at-home red light therapy

Red light therapy devices are sold at health stores and online, typically marketed for the treatment of skin conditions.

While some may be effective for their intended purpose, they’re not powerful enough to treat nerve pain like the devices used by medical professionals.

Does red light therapy work for peripheral neuropathy?

Some research suggests that red light therapy can temporarily reduce chronic and acute pain associated with peripheral neuropathy as well as that of:

• Tendinopathy, pain and loss of function in the tendons
• Fibromyalgia, a chronic condition that causes intense pain
• Several types of arthritis, which cause pain in joints
• Surgery recovery
• Other types of back pain

Research shows red light therapy works to reduce pain and inflammation of peripheral neuropathy in two ways.

Increasing cellular energy production

It stimulates the production of adenosine triphosphate, which stores and transfers the chemical energy needed for almost all cellular processes. This increased energy may help promote healing.

Enhancing blood circulation

It increases blood flow to the treated area, leading to improved oxygen and nutrient delivery to the nerves, promoting regeneration and decreasing inflammation.

UT MD Anderson research echoes these findings. My team measures oxygen levels in patients before and after treatments. When oxygen levels increase, they indicate that red light therapy improves blood circulation and tissue oxygenation in the treated areas.

The oxygen levels are substantially higher right after treatments, and months later, too.

However, more studies are needed to determine effectiveness.

Does red light therapy for peripheral neuropathy pose risks or side effects?

Red light therapy is considered safe when done correctly because it uses very low levels of heat. There’s no exposure to ultraviolet (UV) rays, so it doesn’t damage your skin or increase your risk of skin cancer.

Still, it can cause side effects like skin redness and burning, if the wavelength is too intense or if it’s placed too close to your skin for a long time.

We tell patients to let us know if it’s too hot for their skin and increase the distance between the device and the skin if needed.

Additionally, red light therapy may cause eye damage, so it’s best to wear protective eyewear.

What happens during red light therapy for peripheral neuropathy

Red light therapy involves directing the light onto the affected area for about 60 seconds per site over multiple sessions.

Before receiving treatment in a medical facility, your provider may ask you to describe your pain and numbness levels. This helps them determine the strength of your treatment. Here is what you can expect during this procedure:

1. Because the treatment is usually done on the hands or feet when it’s for peripheral neuropathy, there is no need to undress. But you may remove your shoes and socks if your feet are getting treated.
2. You will sit or stand, with your hands or feet on a chair or medical table.
3. Your provider will hold a device over the affected area, covering each area for between 60 seconds per affected site. There should not be any pain or discomfort during the treatment.
4. After you’re done, you can immediately return to your daily activities.

At UT MD Anderson, I typically schedule patients for three or more treatments. They can be completed on any schedule, whether it’s on consecutive days or spread out over several weeks or months. Some patients request additional sessions, and I’m OK with this. Some patients come in more regularly.

What is the best treatment for peripheral neuropathy?

Peripheral neuropathy treatment can vary widely based on what’s causing it. It can include:

• Talk therapy, to help you manage living with pain
• Medications, such as pills you take by mouth, injections and pain-relieving patches applied on the skin
• Physical therapy to relieve pain, improve balance and prevent falls
• Devices and wearable equipment like braces, canes and prescribed footwear
• Other complementary treatments like acupuncture
• Scrambler therapy, a non-invasive treatment that uses mild electrical impulses to retrain the brain to reduce pain perception
• Transcutaneous electrical nerve stimulation, also known as TENS, another non-invasive procedure that applies low-voltage currents to block pain signals
• Implantable devices that stimulate the spinal cord
• Surgery to sever or reconnect trapped or malfunctioning nerves (in severe cases)

We have many types of treatments to help patients with peripheral neuropathy.

Who should consider red light therapy for neuropathy?

If front-line treatments like medications and electrical stimulation haven’t helped ease your nerve pain, red light therapy may be worth trying. It’s not invasive, unlike more serious surgical interventions.

This should come before invasive procedures.

Billy Huh, M.D., Ph.D., is a pain medicine specialist at UT MD Anderson.

Request an appointment at UT MD Anderson online or call 1-877-632-6789.

Neuropathy is the clinical term for nerves that are not working properly.

From a structural perspective, that could mean they’re either broken or just malfunctioning. Usually, those two things go hand in hand, but not always. Either way, it means that the nerves are not doing what they’re supposed to be doing.

Neuropathy is a problem for many of our patients here at UT MD Anderson because it can be a side effect of some of the drugs we use to treat cancer, including certain types of chemotherapy. But what else might cause neuropathy? And what can we do to treat or even prevent it?

Here’s what to know about neuropathy, including why it happens, how it can look, and why we’re more focused on prevention right now than treatment.

What are the symptoms of neuropathy?

The nervous system is our bodies’ way of interacting with and making sense of the world. We perceive it through our five senses, process that information, then respond, based on how our brains interpret it.

Some of these processes we can control, such as reaching for a pencil or a cup of coffee. Others just go on in the background, like regulating our body temperature, blood sugar and blood pressure. When the nervous system is damaged, though, any of these processes might be affected. So, here are some of the many ways neuropathy can look:

• Autonomic: If the nerves controlling automatic processes are affected, you might faint due to a sudden drop in blood pressure or have heart palpitations.
• Central nervous system: If the nerves in your brain are affected, you might struggle with attention, memory or multitasking.
• Cranial: If the nerves in your ears are affected, you might experience tinnitus (ringing) or have trouble hearing.
• Motor: If the nerves in your muscles are affected, you might experience weakness, cramps or twitching.
• Peripheral: If the nerves in your skin are affected, you might experience numbness, tingling, or excessive sensitivity, sometimes to cold.

What are the main causes of neuropathy?

Among cancer patients, neuropathy is usually due to chemotherapy. These could be platinum-based drugs, such as carboplatin and cisplatin, or taxane-class drugs like paclitaxel.

Chemotherapy is a cytotoxin, meaning that it kills cells. Some cancer cells are more vulnerable to it than others. Unfortunately, our nerve cells share that same quality. So, if they’re left unprotected during treatment, they can be damaged early on.

But chemotherapy isn’t the only possible cause of neuropathy. Others include:

• Alcohol abuse
• Autoimmune disorders, such as lupus and rheumatoid arthritis
• Diabetes
• Injury, such as carpal tunnel syndrome, which results from repetitive motions
• Kidney disease
• Viral infections, such as HIV, Epstein-Barr, herpes, cytomegalovirus, hepatitis and others
• Vitamin deficiency, especially vitamin B