Nervous system side effects are common from cancer and cancer treatments. The nervous system is made up of the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is made up of the brain and spinal cord. The PNS is made up of the nerves outside of the CNS that carry information back and forth between the body and the brain. The PNS is involved in movement, sensing (touching, hearing, seeing, tasting, and smelling), and functioning of the internal organs, (for example, the stomach, lungs, and heart).

Types of nervous system side effects

Some nervous system side effects that may result from cancer or cancer treatment include the following:

• Hearing loss and/or tinnitus (ringing in the ears)
  
  
• Vision loss and/or vision side effects (such as blurred or double vision)
  
  
• Speech difficulties, such as slurred speech, difficulty expressing oneself or understanding speech
  
  
• Cognitive changes including decreased memory, problem solving, and calculation
  
  
• Changes in taste and smell
  
  
• Difficulty swallowing
  
  
• Problems with balance, dizziness, vertigo (feeling like the room is spinning), and nausea
  
  
• Problems with coordination (known as ataxia) and movement, including problems with posture, walking, or holding objects
  
  
• Generalized weakness (known as asthenia), characterized by an overall lack of bodily strength; weakness on one side of the body (known as hemiparesis); drowsiness
  
  
• Paralysis of different parts of the body, ranging from paralysis of one side of the body (known as hemiplegia) to paralysis of a smaller area, such as the facial muscles
  
  
• Seizures
  
  
• Changes in the functioning of organs, resulting in symptoms such as constipation, incontinence (inability to control the flow of urine), and impotence (an inability to achieve or maintain an erection)
  
  
• Pain, resulting from compression of nerves by a tumor or injury to the nerves caused by treatment
  
  
•  Peripheral neuropathy, a condition caused by damage or irritation to the peripheral nerves. The symptoms may include numbness, tingling ("pins and needles"), or burning pain in the arms, hands, legs, or feet; decreased ability to sense hot and cold; difficulty lifting the feet or toes; difficulty picking up small objects; decreased muscle strength; vision or hearing changes; and/or constipation

Causes

Nervous system side effects are caused by many factors, including cancer, cancer treatments, other medications, or other disorders. The symptoms may lead to a cancer diagnosis, appear soon after treatment, or may appear several years after treatment. Possible causes include the following:

• Cancers that affect the nervous system, such as brain cancer and sarcomas of the nerves (for example, neurofibrosarcoma, malignant peripheral nerve sheath tumor, and peripheral primitive neuroectodermal tumor)
  
  
• Cancers that metastasize (spread) to the brain or spinal cord
  
  
• Cancerous tumors growing in other parts of the body that press on nerves
  
  
• Some types of chemotherapy may cause peripheral neuropathy, such as bortezomib (Velcade), carboplatin (Paraplat, Paraplatin), cisplatin (Platinol), docetaxel (Taxotere), oxaliplatin (Eloxatin), paclitaxel (Taxol), thalidomide (Synovir, Thalomid), vinblastine (Velban, Velsar) and vincristine (Oncovin, Vincasar).
  
  
• Other types of chemotherapy may cause a variety of other nervous system side effects. These types include cytarabine (ara-C, cytosine, arabinoside), fluorouracil (5-FU, Adrucil), ifosfamide (Cyfos, Ifex, Ifosfamidum), interferon (multiple brand names), fludarabine (Fludara), and methotrexate (multiple brand names).
  
  
• Radiation treatment, especially to the head and neck, or whole-body radiation treatment
  
  
• Radiation treatment to the spine, or chemotherapy injected directly into the spine
  
  
• Surgery, if nerves are damaged or disrupted during surgery to remove a cancerous tumor or to perform a biopsy (removal of a small amount of tissue for examination under a microscope)
  
  
• Specific medications, including some antinausea drugs, opioid (strong) pain killers, and anticonvulsants (drugs to treat seizures)
  
  
• Infections causing swelling or inflammation of the brain, spinal cord, or inner ear
  
  
• Other conditions or symptoms related to cancer or cancer treatments, including anemia, dehydration, fatigue, stress, and depression
  
  
• Other conditions or disorders not related to cancer, such as diabetes, vitamin deficiency, thyroid dysfunction, human immunodeficiency virus (HIV), stroke, Alzheimer’s disease, multiple sclerosis, and nerve injury

Management

Nervous system side effects can make it difficult for people to complete normal, daily activities. Some symptoms caused by cancer treatment will go away after treatment ends, but some may continue indefinitely. Although nerve damage and nervous system side effects may not be preventable, most are effectively treated if diagnosed early. Early treatment can also prevent symptoms from becoming more problematic. It is important to tell your doctor immediately if you have any symptoms that could show a nervous system disturbance. Once diagnosed, management of nervous system side effects depend on the type of disturbance and the underlying cause. These may include the following:

• Antinausea and antivertigo medications, such as meclizine (multiple brand names), prochlorperazine (Compazine, Compro), scopolamine patch (Scopace, Transderm-Scop)
  
  
• Antibiotics (to treat infection), and corticosteroids (to reduce inflammation and swelling)
  
  
• Pain medications, including opioids, as well as tricyclic antidepressants such as amitriptyline (multiple brand names), nortriptyline (Aventyl, Pamelor), and/or anticonvulsants, including gabapentin (Neurotonin) and pregabalin (Lyrica) used to treat peripheral neuropathy and other types of nerve pain (known as neuropathic pain)
  
  
• Nerve blocks and transcutaneous electric nerve stimulation (TENS), which provide pain relief
  
  
• Occupational therapy, to enhance motor skills needed for daily activities, such as getting dressed, picking up small objects, writing, or doing household chores
  
  
• Physical therapy, to improve physical strength, balance, coordination, and mobility
  
  
• Speech therapy, to improve speech and learn adaptive techniques for alterations in speech
  
  
• Evaluation by a neuropsychologist to assess cognitive dysfunction
  
  
• Changes to the home environment to increase safety, such as installing hand rails in the bathroom, using nonskid rugs, adding extra lighting, and checking water temperature with the elbow rather than the hands

More Information

Cognitive Problems

Managing Side Effects

Last Updated: June 30, 2009