This is the treatment given to prevent lymphoma from spreading to the central nervous system (CNS). The central nervous system includes the brain and spinal cord.
Most patients with lymphoma do not need this type of treatment. The doctor might recommend this treatment for certain types of lymphomas or risk factors that could put a patient at higher risk of their lymphoma spreading to the central nervous system (CNS). CNS prophylaxis is given to kill the cancer cells that may be in the brain and spinal cord, even though no cancer has been detected there.
What is the central nervous system?
The central nervous system is made up of the brain, spinal cord, and the eyes.
The brain is made up of:
- The cerebrum: this controls our speech and understanding, our sensations and voluntary movements (the movements we decide to make)
- The cerebellum: helps with movements and controls our balance
- The brainstem: controls essential body functions, such as our breathing, heart rate and blood pressure
The spinal cord runs from the brain down the back within the bones of the spine. A series of nerves join directly onto the spinal cord. The nerves carry information about sensation from around the body and transmit messages to control the muscles of the body.
Cerebrospinal fluid (CSF) surrounds the brain and spinal cord. The CSF cushions the brain and spinal cord, to prevent it from harm.
The blood-brain barrier surrounds the brain. It is a barrier of cells and blood vessels that only lets certain substances reach the brain to protect it from harmful chemicals and infections. It also prevents or interferes with many chemotherapy drugs passing from the blood to the brain.
Who might need CNS prophylaxis?
- Patients with aggressive (fast growing) types of lymphoma such as a Burkitt lymphoma and lymphoblastic lymphoma are known to spread to the CNS
- Patients with diffuse large B-cell lymphoma (DLBCL) that is in places of the body such as the breast, testicle, adrenal gland, or kidney. These sites are known to spread to the brain and therefore precautions are taken to prevent the spread of lymphoma.
- If the lymphoma is located close to the skull or spinal cord
- If there are 2 or 3 risk factors such as high lactate dehydrogenase (LDH) levels in the blood, are over 60, the lymphoma is in multiple extranodal sites or stage 3 or 4 DLBCL
How is CNS prophylaxis given?
CNS prophylaxis can be given in two ways:
- Intrathecal chemotherapy – This method is given directly into the CSF. The CSF (Cerebrospinal fluid) is the fluid that surrounds the brain and spinal cord to keep them safe from injury. This method is used when the drug is unable to cross the blood brain barrier. This method avoids the blood-brain barrier. The chemotherapy is injected during a lumbar puncture. Only certain chemotherapy can be given into the CSF. The most common drugs used are methotrexate and ARA-C (cytarabine).
- Intravenous chemotherapy – This chemotherapy is given into a vein via a cannula or central venous access device. These drugs can cross the blood-brain barrier. Chemotherapy drugs that can pass through the blood-brain barrier include high-dose methotrexate, ifosfamide and cytarabine.
High dose methotrexate is often given for 2 cycles after your standard treatment (e.g. R-CHOP). This treatment is given as an inpatient in hospital over 3-5 days. The medical team will give detailed information about the treatment and side effects