Polyneuropathy in the Feet: Diabetes, Chemotherapy and Nerve Pain

Medical news and patient education from Family Foot & Leg Center, PA.

Polyneuropathy in the feet affects many nerves at once, typically beginning in both toes and moving upward. Diabetes and some chemotherapy drugs are important causes, but not the only ones. Burning pain, electric-shock sensations, numbness and balance problems deserve an evaluation because treating pain alone does not necessarily stop the underlying nerve injury.

How common is polyneuropathy, and how often does it hurt?

A review of population studies estimated polyneuropathy in about 1% of the general population, rising to as many as 7% of older adults. Estimates vary with the age of participants and the way nerve damage is measured. A separate clinical review of distal symmetric polyneuropathy reported neuropathic pain in approximately one-third of affected patients. These figures are not a count of all neuropathic pain in the general population: not everyone with nerve pain has polyneuropathy, and some people with polyneuropathy feel numbness without pain.

That numbness matters. Reduced feeling can make a blister, cut or foot wound difficult to detect, particularly in people with diabetes.

What percentage of lower-extremity polyneuropathy is due to diabetes?

In studies summarized by the distal symmetric polyneuropathy review, diabetes accounted for 32%–53% of cases and 24%–27% remained without an identified cause after evaluation. These percentages describe the causes among people with this common form of polyneuropathy; they are not percentages of all adults. The review also names alcohol exposure, vitamin B12 deficiency, chronic kidney disease, inherited disorders and chemotherapy among important causes, but does not provide a dependable population-wide percentage for each of those groups.

Diabetes and chemotherapy can occur in the same person. Even with a known risk factor, a clinician should consider whether a separate, treatable problem such as vitamin deficiency or a compressed nerve contributes to the symptoms. A painful spot in one nerve’s territory is different from a symmetrical pattern that starts in both feet.

Chemotherapy-induced peripheral neuropathy: symptoms can last

Cancer medicines including taxanes, platinum drugs, vinca alkaloids and bortezomib can injure peripheral nerves. Patients may notice tingling, burning, numbness or difficulty with balance in the feet, sometimes with similar symptoms in the hands. The risk varies by drug, dose and individual health.

A systematic review and meta-analysis estimated chemotherapy-induced peripheral neuropathy in 68.1% during the first month after chemotherapy, 60.0% at three months and 30.0% at six months or later across the studied groups. These are estimates of nerve symptoms, not the percentage of patients with painful neuropathy; the included studies and estimates varied substantially. Tell your oncology team promptly about new numbness, pain or weakness. Do not change cancer treatment without speaking with that team.

What does a useful foot-and-nerve assessment include?

Family Foot & Leg Center, PA approaches neuropathy in the context of the foot and lower leg: where symptoms occur, whether both sides are affected, how sensation and strength have changed, and whether there are skin wounds, circulation concerns or difficulty walking. A medication and chemotherapy history helps distinguish potential causes. Depending on the findings, the clinician may coordinate blood tests or specialist evaluation for diabetes, vitamin B12 deficiency and other causes.

People who have reduced sensation need a foot-protection plan even when pain medication works. The goal is to keep patients safely walking and engaged in activities such as golf, pickleball and running, while reducing the chance that a small injury goes unnoticed.

Treatment options: what each one can and cannot do

The right treatment depends on the cause and the pattern of pain. Medicines can reduce pain; decompression can address a documented nerve entrapment; stimulation can target selected severe peripheral nerve pain. None of those interventions should be presented as a universal cure for diffuse polyneuropathy.

Medication and care for the underlying condition

For painful diabetic neuropathy, clinicians may consider medicines such as duloxetine, pregabalin or gabapentin, selecting them around other medical conditions and possible side effects. Diabetes care, foot checks, footwear and fall prevention remain important whether or not medication relieves pain.

For established painful chemotherapy-induced neuropathy, the American Society of Clinical Oncology guideline update identifies duloxetine as the drug with the strongest supporting evidence, while noting that benefit is limited. Pain medicine does not replace oncology follow-up, and the evidence for diabetic neuropathy should not automatically be applied to chemotherapy neuropathy.

Dr. Dellon’s nerve-decompression approach

The lower-extremity nerve-decompression approach associated with Dr. A. Lee Dellon releases pressure at a specific nerve site. It is most relevant when an evaluation suggests focal entrapment alongside widespread neuropathy, not simply because a patient has diabetes or numb feet. Surgery cannot remove the underlying metabolic or chemotherapy-related cause of diffuse nerve damage.

The evidence warrants balance. A 2022 review pooling five randomized trials did not find statistically significant improvements in several pooled measures; a later controlled trial found lower reported pain after lower-extremity decompression in selected people with painful diabetic neuropathy who had not improved after a year of medical treatment. Patients should discuss selection criteria, surgical risks and realistic goals with their surgeon. Results in diabetic neuropathy should not be assumed to apply to chemotherapy-induced neuropathy.

Bioventus peripheral nerve stimulation

Peripheral nerve stimulation delivers electrical pulses near a selected nerve as a way to manage pain. According to Bioventus StimRouter prescribing information, it is indicated as an adjunct for adults with severe, difficult-to-treat chronic pain of peripheral nerve origin. That indication does not mean it reverses nerve damage or is right for every person with diffuse diabetic or chemotherapy-related pain.

Assessment includes the location of pain, a plausible nerve target, treatments already tried, and device safety restrictions. Family Foot & Leg Center can discuss whether this option warrants evaluation and coordinate care with the patient’s other clinicians.

Frequently asked questions

Can diabetes and chemotherapy both cause numbness in the feet?

Yes. Both can injure nerves and can affect the same person. A clinician should also check whether another condition or a separate compressed nerve contributes to the symptoms.

Does everyone with polyneuropathy have nerve pain?

No. A clinical review reported neuropathic pain in about one-third of patients with distal symmetric polyneuropathy. Numbness without pain can still raise the risk of an unnoticed foot injury.

Will nerve decompression or stimulation cure polyneuropathy?

Neither is a universal cure. Decompression addresses selected compressed nerves; stimulation manages selected chronic peripheral nerve pain. Treating the cause and protecting the feet remain essential.

Specialist foot-and-leg care in Southwest Florida

Family Foot & Leg Center, PA provides specialist foot and ankle care from the Marco Island area to Sarasota, including Naples, Estero, Fort Myers, Cape Coral and Port Charlotte. Its clinicians evaluate how nerve symptoms affect foot safety, balance and movement, and help patients understand when medication, an assessment for nerve entrapment or an evaluation for peripheral nerve stimulation makes sense.

New or worsening numbness, burning or weakness deserves an assessment, particularly if you have diabetes or a foot wound. Book an appointment online or call 239-430-3668. Seek urgent care for a newly infected foot wound, rapidly worsening weakness or a cold or discolored foot.

Learn more about peripheral neuropathy evaluation and treatment and diabetic foot care at Family Foot & Leg Center.

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This article is for education and does not diagnose an individual condition or guarantee a treatment result.