Have you ever felt a sudden numbness in your hand or a weakness in your leg and brushed it off as fatigue or sleeping in a weird position? Most of the time, it’s nothing serious, but sometimes, these subtle changes could be early signs of something more serious, including cancer. Understanding when your body is sending a warning signal can make a huge difference. Here’s what you should know.

How common are neurological symptoms in cancer?

You might be surprised, but neurological symptoms aren’t rare in cancer patients. About 15–20% of people with cancer experience issues like numbness, weakness, or tingling during their illness.

Even brain metastases—cancer that spreads to the brain—can show up as neurological symptoms. A 2025 study of 716 breast cancer patients with brain metastases stated 80% experienced problems like weakness, seizures, or changes in thinking right at the time of diagnosis.

Reasons behind the symptoms

Here are some possible culprits:

• Brain Tumours: Tumours in either the parietal or temporal lobes may result in weakness or numbness on one side of the body, problems with coordination, or difficulty with localizing position.
• Leptomeningeal Disease: When cancer cells migrate into the cerebrospinal fluid that surrounds the brain and spinal cord, they cause this condition. The symptoms can be balance issues, vision alteration, weakness, or seizures.
• POEMS Syndrome: This is a rare but severe syndrome associated with cancer. It may lead to peripheral neuropathy, enlarged organs, hormonal issues, and even skin changes.

Behind every symptom, there’s a story waiting to be uncovered

If you experience these symptoms, doctors might recommend:

• MRI or CT scans to check for tumours or metastases
• Lumbar puncture to examine cerebrospinal fluid
• Electromyography (EMG) and nerve conduction studies to assess nerve function

When should you see a doctor?

Don’t wait if you notice:

• Sudden numbness or weakness
• Symptoms that keep getting worse
• Other concerning signs, like slurred speech, vision changes, or seizures

It is important to notice warning signs early. Paying attention to your body and seeking assistance early enough not only provides a doctor with an increased opportunity to address the problem and provide a lasting solution but also allows you to preserve your health and inner calm. Your health is something to listen to—act now before it is too late.