Highlights from the Neuropathy & Cancer AppChat Sponsored by Seattle Genetics and ReVital Cancer Rehabilitation

Missed the Neuropathy & Cancer AppChat with cancer rehabilitation expert Dr. Stubblefield? Attended and want a recap? No worries, we’ve got you covered! Read below to find out what information Dr. Stubblefield shared during the AppChat as well as what questions he answered from those in attendance. You’ll also find more information on Dr. Stubblefield, resources and our sponsors!

Part I: Neuropathy & its Signs/Symptoms

Information from Dr. Stubblefield:

The central nervous system (CNS) consists of the brain and spinal cord. The peripheral nervous system (PNS) consists of everything outside of the brain and spinal cord. Nerve roots come out of the spinal cord, literally resembling the roots of a tree, join into complex interconnections called plexuses, and then branch into large-named nerves, such as the sciatic nerve, which travel to the rest of the body.

There are motor nerves which supply impulses to the muscles, sensory nerves which relay sensation from the body, and autonomic nerves which control things like blood pressure and digestion.

When we talk about peripheral neuropathy (PN) we are talking about damage to the nervous system outside of the brain and spinal cord.

There are three major types of neuropathy problems:

Sensory problems: This is usually pain or the loss of the ability to feel. Sometimes it presents as numbness and/or tingling, which we call paresthesia.

Motor problems: This is the loss of the ability to work the muscle, which presents as weakness. It usually occurs distally out in the hands or out in the feet.

Autonomic problems: The autonomic nervous system, which is part of the PNS, controls bodily functions such as digestion, heart rate, blood pressure, and sexual arousal. These functions may be altered by damage to the PNS.

Different causes of neuropathy will affect the different parts of the PNS differently. For example, platinum drugs primarily damage sensory nerves. You may have pain and lose the ability to know where your joints are in space, but your muscles still remain strong. Severity of neuropathy can also vary widely. Neuropathy could just be numbness in your fingers or, in extreme cases, it can cause paralysis.

Q&A with Dr. Stubblefield:

Q: Can neuropathy affect the face?
A: Neuropathy of the face does happen, but it’s rare. It’s usually a vasculitic phenomenon.

Q: Are muscle fasciculations a form of neuropathy? 
A: Muscle fasciculations, or muscle twitching, can be caused by neuropathy. Motor nerves can send false signals to the muscle, which spasms in response.

Q: Can neuropathy cause erectile dysfunction (ED)? 
A: It absolutely can. It can occur from damage to the autonomic nervous system. It’s relatively rare though and the neuropathy is usually significant elsewhere. If it is only ED, then we would look for other causes.

Q: Can neuropathy cause toe cramps? 
A: It absolutely can. If the motor nerves are damaged and send false signals to the muscles of the toe.

Q: My neuropathy pain is much worse in the cold. What causes neuropathy pain to worsen in the cold? 
A: It is very common for neuropathy to become more painful in the cold. The cold makes the nerves fire differently, causing more pain.

Q: Is it common to have no symptoms of neuropathy during chemotherapy, but have it develop after chemotherapy has ended? 
A: Yes, it is common with agents such as the platinum drugs and is known as “coasting”.

Part II: Causes of Neuropathy

Information from Dr. Stubblefield:

In the world, the most common cause of neuropathy is leprosy. In the United States, the most common cause of neuropathy is diabetes. While in cancer, the most common cause is chemotherapy — particularly the vinca alkaloids, the taxanes and the platinum drugs.

Different chemotherapies can cause different types of neuropathy.

For example:

The vinca alkaloids and taxanes are what we call tubulin inhibitors. Tubulin is a type of protein that acts similarly to a pulley system. Among other things, cells use tubulin to divide. Tubulin inhibitors disrupt the process of cell division and cause the cell to die. If it is a cancer cell, this is a good thing. If it is a normal cell, this can lead to unwanted side effects. Tubulin inhibitors affect both sensory and motor nerves equally. Platinum drugs target the DNA of the cell and cause changes in normal cell functions, such as the ability to repair DNA and/or create new DNA. They only affect sensory nerves and not the motor nerves. To the trained eye, tubulin inhibitors and platinum drugs result in very different types of neuropathy.

A number of things can mimic chemotherapy-induced PN. Both a pinched nerve, which may be caused by bad arthritis or a disk herniation in the back, and carpal tunnel syndrome can cause numbness and tingling. These effects can be easily mistaken for PN.

More than one factor can contribute to neuropathy. A good neuromuscular medicine clinician should be able to sort out the cause or causes of the neuropathy.

Q&A with Dr. Stubblefield:

Q: Does chemotherapy-induced PN develop immediately or over time?
A: It depends on the chemotherapeutic agent. Neuropathy is an immediate side effect of the vinca alkaloids and taxanes, but it usually gets better once you’ve stopped the chemotherapy. Platinum drugs affect the DNA, which means neuropathy is more likely to develop over time and may continue to get worse 6 to 9 months after you’ve stopped chemotherapy. This is referred to as the coasting effect.

Q: How common is neuropathy in patients that have been treated with platinum drugs?
A: It depends on the dose. Most patients will get some neuropathy, but it typically goes away for a significant percentage of them.

Q: Why are some people more susceptible to chemotherapy-induced PN?A: A person may be more susceptible to chemotherapy-induced PN if there is a pre-existing issue, such as diabetes, or even a pinched nerve somewhere. This can make the nerves more sensitive to chemotherapy. Sometimes there is no identifiable reason.

Q: What about radiation? What kind of neuropathy is most typical following radiation? Is it more immediate or can it be delayed?
A: Big and good question. It depends. Radiation does not cause a PN. It only damages the nerves that are inside the radiation field.

Part III: Evaluation of Neuropathy

Information from Dr. Stubblefield:

Diagnosing neuropathy can be very simple or one of the most complicated things in medicine. When a patient without any evidence of neuropathy before chemotherapy develops typical signs and symptoms of neuropathy in the treatment setting, we assume it is chemotherapy-induced PN and we don’t do any additional investigation.

When someone develops neuropathy that is not typical, then we will investigate using a detailed history and specialized physical examination. If that doesn’t get to the bottom of things, we consider nerve testing (nerve conduction studies and electromyography (EMG)), specialized laboratory studies, and sometimes imaging.

There are many nerve issues that might not have caused issues before treatment that can come out as a result of it. Much of the testing is to ensure that isn’t another type of neuropathy (vitamin B12 deficiency, diabetes, Lyme disease, etc.) or a mimic of neuropathy, such as spinal stenosis (narrowing) which compresses the nerves coming out of the spine.

Q&A with Dr. Stubblefield:

Q: Where do I find a neuromuscular medicine clinician? What qualifications should I be looking for?
A: Most neurologists have at least some training. Those with a board certification in electrodiagnostic medicine, such as EMG, are even better. Rehabilitation physicians are also experts in neuromuscular medicine.

Part IV: Treatment of Neuropathy

Information from Dr. Stubblefield:

Numbness: Unfortunately, nothing really works for numbness caused by neuropathy. Feeling is lost because the nerve is not functioning or is dead.

Pain: Pain is different. In pain, the nerve is not dead, but it is sending false signals into the spinal cord and brain which are perceived as pain.

Very often those with pain respond well to medication. One of the best studied drugs for chemotherapy-induced PN pain is duloxetine (Cymbalta). Gabapentin (Neurontin) and pregabalin (Lyrica) have a different mechanism of action than duloxetine but, from my experience, can also be very effective for pain. Tricyclic antidepressants (such as, nortriptyline and amitriptyline) may also be very helpful. If non-opioid options are exhausted, sometimes we have to try opioid-type medications for pain management. These are usually effective.

Some patients use topical medication for the pain, such as lidocaine patches or topical creams compounded by pharmacists. They are not really absorbed and as a result don’t get into the CNS, but some patients swear by them.

Supplements are generally not going to make you better, unless you have a specific nutritional deficiency. Many National Cancer Institute studies have looked at various supplements in the treatment of chemotherapy-induced PN, but unfortunately none have been positive.

A vitamin B12 deficiency can cause neuropathy. Vitamin B12 is a common supplement people get for neuropathy and, if you are vitamin B12 deficient it can be curative, but for chemotherapy-induced PN it’s not.

Alternative treatments for pain management exist too, such as acupuncture, exercise and neuromodulation or scrambler therapy. My personal sense is that acupuncture is most likely to work when you believe it will work. In scrambler therapy electrical impulses on the skin are sent to overwhelm pain signals with non-pain signals.

Problems with Day-to-Day Activities: Therapy can help improve balance, coordination, dexterity and strength issues caused by neuropathy. Physical therapists can help with balance and walking (gait) issues — making patients more mobile and less likely to fall. Occupational therapists can help with strength and dexterity. They can also give you tricks to make everyday tasks easier. Therapy is not necessarily a cure, but almost everyone can become more functional and more comfortable.

Q&A with Dr. Stubblefield:

Q: What is more common in patients with chemotherapy-induced PN: numbness, pain, or both equally?
A: Both numbness and pain are very common. Numbness is a little more common. Pain is easier to treat.

Q: Is there one drug that works better for pain than others?
A: Not necessarily. Just because you don’t respond well to one drug, doesn’t mean that you won’t respond well to another drug. The drugs used to treat pain do not all act at the same target. Also, we’re all wired a little differently and, therefore, respond differently.

Q: Would cannabis or cannabidiol (CBD) oil help neuropathy symptoms?
A: There is very little high-quality data yet. I hope that once we get better clinical trials we are able to gain a better idea of whether or not it is effective.

Q: Would someone that had slightly low vitamin B12 levels before chemotherapy be more susceptible to neuropathy?
A: Yes, and it would be worth replacing the vitamin B12.

Q: Is there any negative effect of taking vitamin B12?
A: No, not at all.

Q: For problems with the autonomic nervous system, can you only treat the neuropathy symptoms or can more be done?
A: It is supportive treatment. There is no specific treatment to make the nerves work better.

Q: Any other non-pharmacological tips for dealing with neuropathy?
A: Keeping the skin in good condition with lotion can help. Avoiding constricting garments, such as socks, can also be helpful.

Q: What, if anything, can be done to prevent neuropathy if you had treatment and no neuropathy so far? Any measures that should be taken to avoid late effects in general?
A: Unfortunately, there is no treatment to prevent late effects. The treatments currently available optimize your function and control symptoms if they develop.

Q: What’s on the horizon? Do any new treatments look promising?
A: There are new medications in development to help with pain, but nothing curative as yet.

For more information on Dr. Michael D. Stubblefield.

For more information on chemotherapy-induced PN, check out Dr. Stubblefield’s recommended links:

Overview of chemotherapy-induced PN.

Understanding chemotherapy-induced PN.

Symptoms of chemotherapy-induced PN.

More on our sponsors:

Seattle Genetics

ReVital Cancer Rehabilitation

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Disclaimer: All content is for informational purposes only. Content is not intended as a substitute for medical advice or treatment. Consult your medical professional for any questions concerning your health.