Chemotherapy medications can come in many forms and types (oral, injectable, inhaled, etc.). If you need medication, the type that’s right for you will depend on how the medication works and the treatment you need.

If you have a diagnosis of cancer that affects your central nervous system (brain and spinal cord), your doctor may recommend intrathecal chemotherapy treatment.

Intrathecal chemotherapy is a type of cancer treatment that targets your cerebrospinal fluid (CSF). CSF is a colorless fluid that’s mainly produced by the ventricles in the brain. It surrounds your brain and spinal cord to protect them from injury.

Read on to learn more about what intrathecal chemotherapy is, its uses and side effects, and what to expect when you need this therapy.

Chemotherapy treatment aims to kill cancer cells or stop them from spreading. It’s usually given as pills you swallow or as an intravenous (IV) injection into your veins.

But when cancer is in the central nervous system, chemotherapy treatments given through IV or by mouth aren’t as effective.

This is because there’s a layer of protection around the central nervous system called the blood-brain barrier. This barrier allows necessary nutrients and oxygen to enter the brain while keeping out toxins and other harmful substances.

Unfortunately, the blood-brain barrier can also block much of the cancer medications taken by mouth or given through IV, making it less effective.

Your doctor may opt for intrathecal chemotherapy to deliver more targeted chemotherapy treatment to your central nervous system.

Your doctor may recommend intrathecal chemotherapy for two main reasons:

  • to target cancer cells in the space around the brain and spinal cord
  • to prevent cancer from reaching the CSF from other areas of your body

Intrathecal chemotherapy is more effective because it targets the CSF directly.

Certain types of cancers are more likely to spread to your central nervous system, including:

In these cases, your doctor may recommend intrathecal chemotherapy to prevent cancer from reaching your CSF or to treat cancer cells that have spread to the central nervous system.

Your doctor may also recommend intrathecal chemotherapy if other types of cancer — like breast, lung, and melanoma — have spread to the CSF.

Once your doctor makes a diagnosis, they’ll go over your treatment plan, including medication options and how the medication will be given.

Medications and dosing

The dose of the intrathecal chemotherapy treatment depends on if it’s used to prevent or treat cancer, along with many other factors like your overall health, age, and weight.

Medications such as cytarabine and methotrexate are often used alone or together in intrathecal chemotherapy. Corticosteroid medications may be added to prevent inflammation and irritation of the arachnoid membrane (arachnoiditis).

Type of procedures used

Intrathecal chemotherapy can be given in two ways:

  • Lumbar puncture. A lumbar puncture (spinal tap) is a way to access your spine and deliver the medication to your CSF. It’s the same procedure your doctor probably did to test your CSF for cancer cells.
  • Ommaya reservoir. If your doctor thinks you may need multiple intrathecal chemotherapy treatments, they might recommend placing an Ommaya reservoir. This method allows safe, repeated access to your CSF so the medication can go where it’s needed.

Lumbar puncture

With this approach, the medication is injected into your CSF, between two vertebrae in your lower spine.

Before you have a lumbar puncture procedure, you will have lab tests done to make sure you have enough platelets for your blood to clot properly after the procedure.

You’ll be asked to lie on your side or sit with your head and chest resting on a surface to expose your spine. The area will be numbed with an anesthetic to prepare for the injection. You may feel some pressure but shouldn’t feel pain at the injection site.

The process usually takes around 30 minutes to give the medication. You’ll need to stay still for 30 to 60 minutes for the drug to move through the CSF.

Ommaya reservoir

An Ommaya reservoir is a small plastic dome-shaped device that’s surgically implanted under your scalp. It has a catheter (tube) attached that allows medication to reach an open space in your brain where CSF flows.

When chemotherapy medication is injected into the reservoir, it flows into the CSF without the need for spinal taps each time. This makes it a good option for people who need multiple treatments.

This reservoir also allows the doctor to take samples of your CSF fluid to see how your treatment is going, without the need for a lumbar puncture.

This is a surgical procedure and has some potential risks, including:

  • infection
  • bleeding into the brain
  • loss of brain function

A neurosurgeon will implant the reservoir while you’re under general anesthesia. Your doctor will review your overall health for this procedure.

Ask your doctor for information about the Ommaya reservoir and its benefits and risks in your situation.

There are some risks and side effects of intrathecal chemotherapy. These can be from the procedure or the medications.

Some side effects intrathecal chemotherapy can include:

  • weakness or tiredness
  • back pain
  • headache
  • dizziness
  • nausea and vomiting
  • fever
  • allergic reaction to chemotherapy medication

Serious side effects include:

  • seizures
  • confusion
  • difficulty walking or talking
  • spinal fluid leakage from the lumbar puncture site
  • lack of coordination
  • numbness, tingling, or a change in sensation in your arms, hands, feet, or legs
  • paralysis

Call your doctor if you experience serious side effects. If you think you’re experiencing a medical emergency, call 911 or go to an emergency room right away.

Please note that these are not full lists of possible side effects. Ask your treatment provider about specific side effects to watch for in your case, including how to care for your injection site to prevent infections.

Tips for coping with intrathecal chemotherapy treatment

  • Ask your doctor what to expect before and after treatment and how to manage any side effects.
  • Pack a bag with your comfort essentials for your chemotherapy appointment.
  • Build a support network of caregivers (family and friends) to help you during treatment. This could mean taking you to appointments, monitoring for any side effects, shopping for essentials, providing healthy meals, or helping with household chores.
  • Try to get enough rest to recover from your treatment, and let your family know what you need.
  • Eat nutrient-rich foods and drink plenty of fluids to stay hydrated. This can help with headaches and other side effects after treatment.
  • Use good infection prevention measures such as handwashing, taking care of your injection site, and avoiding crowds and others who may be sick.
  • It may be helpful to consider joining a support group for advice and encouragement.
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The outlook for cancers that affect the central nervous system can depend on the type of cancer and individual factors like your overall health, genetics, any other conditions you may have.

Early detection and effective treatment are important for your long-term prognosis. Intrathecal chemotherapy is more effective than oral or IV chemotherapy for cancer that’s spread to the central nervous system.

Your doctor can give you specific information about your type of cancer, prognosis, and available treatment options.

It’s totally normal to have questions about your treatment. If you’re feeling overwhelmed, reach out to your medical team and ask questions. Discuss your concerns with your doctor and ask about the risks and the procedure.

You can also bring someone you trust to your appointment, so you feel more comfortable. If you don’t understand something your doctor says, don’t be afraid to ask them to explain. Your good health and recovery is everyone’s goal.