Chemotherapy is a common cancer treatment that uses powerful drugs to destroy cancer cells or slow their growth. While many chemotherapy drugs are administered throughout the body, some cancers require a more direct approach. Intrathecal chemotherapy is a specialized method designed to deliver medication directly to the central nervous system, where it can specifically target cancer cells in the brain and spinal cord.
What Intrathecal Chemotherapy Is
Intrathecal chemotherapy involves injecting anti-cancer drugs directly into the cerebrospinal fluid (CSF), which is the clear fluid surrounding the brain and spinal cord. This fluid serves as a protective cushion for the central nervous system (CNS). The direct administration method is necessary because the brain and spinal cord are protected by a natural defense system called the blood-brain barrier. This barrier prevents most chemotherapy drugs from reaching the CNS effectively.
By bypassing the blood-brain barrier, intrathecal chemotherapy ensures that the medication directly accesses the CSF, allowing it to reach cancer cells that may be present within this fluid or in the meninges, the membranes surrounding the brain and spinal cord. This approach is distinct from systemic chemotherapy, which delivers drugs through the bloodstream to affect cancer cells throughout the body. The goal is to maximize drug exposure in the CNS while reducing widespread systemic side effects.
Conditions It Treats
Intrathecal chemotherapy is primarily used for cancers that have originated in or spread to the brain, spinal cord, or the surrounding meninges. It is commonly employed for certain types of leukemias, such as acute lymphoblastic leukemia (ALL) and Burkitt’s lymphoma, where there is a significant risk of central nervous system involvement.
The treatment may also be used for other lymphomas, including diffuse large B-cell lymphoma, if they have spread to the CNS. Certain solid tumors that have metastasized to the cerebrospinal fluid or meninges may also be treated with intrathecal chemotherapy. This method can be used both to treat existing cancer cells in the CSF and to prevent cancer from spreading to this area.
How It Is Administered
Intrathecal chemotherapy is administered through specific procedures that allow direct access to the cerebrospinal fluid. One common method is a lumbar puncture, often referred to as a spinal tap. During this procedure, a healthcare professional inserts a thin needle into the spinal canal in the lower back, between two vertebrae, to inject the medication directly into the CSF. The area is numbed with a local anesthetic, and patients may be positioned to create space between the spinal bones.
Another method, particularly for patients requiring multiple treatments, involves the surgical placement of an Ommaya reservoir. This small, dome-shaped device is implanted under the scalp and connected to a thin tube, or catheter, that extends into a ventricle of the brain, where cerebrospinal fluid is produced. The Ommaya reservoir allows for repeated, less invasive injections of chemotherapy drugs directly into the CSF without requiring a lumbar puncture each time. Both procedures are performed by a specialist.
Potential Effects
Individuals undergoing intrathecal chemotherapy may experience various effects, most of which are temporary. Common side effects include headache, nausea, and vomiting, sometimes accompanied by a loss of appetite. Patients might also experience dizziness, temporary numbness or tingling in the limbs, or mild back pain at the injection site.
A low-grade fever can occur as a reaction to the treatment. These effects are manageable and tend to resolve within a few hours to a few days after the procedure. Rest and pain relievers can help alleviate discomfort. Patients are encouraged to communicate any concerns or new symptoms to their healthcare team.