Primary central nervous system (CNS) lymphoma (PCNSL) is a type of non-Hodgkin lymphoma (NHL) that starts in the brain or spinal cord (central nervous system or CNS). Most primary CNS lymphomas are B-cell lymphomas, most often diffuse large B-cell lymphomas (DLBCL). T-cell PCNSL is rare.
PCNSL most often occurs in the brain, but it can also occur in the:
PCNSL rarely spreads (metastasizes) outside the CNS.
PCNSL is more common in older adults, but it can occur in people of all ages. PCNSL is an uncommon type of NHL, but its incidence has been increasing.
The main risk factor for developing PCNSL is a weakened or suppressed immune system in people who have:
Symptoms of PCNSL are the same as for other types of brain tumours and depend on the area of the brain that is affected. There are often tumours in many different parts of the brain (multifocal). Some of the signs and symptoms of PCNSL include:
Most of the same tests that are done to diagnose a brain tumour are done to diagnose PCNSL. A stereotactic biopsystereotactic biopsyA procedure that uses a 3-dimensional scanning machine ( ultrasound, CT scan or MRI) to find the precise location of a tumour and remove a sample for examination under a microscope. is usually done to get some tissue to confirm a diagnosis of PCNSL, especially in people who do not have AIDS.
Lymphomas or other types of cancer that start in other parts of the body can spread (metastasize) to the brain, but these are not primary CNS lymphomas.
PCNSL is usually a fast-growing (aggressive) lymphoma. PCNSL often recurs after treatment. In general, the prognosis for PCNSL is poor. Some factors that affect the prognosis of people with PCNSL are:
The treatment of PCNSL depends on the person’s age, performance status and whether or not the person has a decreased ability to fight infections (is immunosuppressed).
CorticosteroidsCorticosteroidsAny steroid hormone that acts as an anti-inflammatory by reducing swelling and lowering the body’s immune response (the immune system’s reaction to the presence of foreign substances). are often used to treat PCNSL because it responds very well to corticosteroid therapy. Drugs like prednisone (Deltasone) are used to:
When PCNSL is suspected, corticosteroids are usually not given until after diagnostic tests are done because these drugs can significantly decrease the size of tumours and affect test results.
Chemotherapy is the main treatment for PCNSL. The chemotherapy drugs commonly used for NHL are not effective against PCNSL because these drugs do not reach the brain or cross the blood-brain barrier. The blood-brain barrier protects the brain and prevents many chemotherapy drugs from reaching brain tumour cells in large enough amounts to destroy them. Chemotherapy drugs used to treat brain tumours because they can cross the blood-brain barrier include:
PCNSL may also be treated with intrathecal chemotherapy (chemotherapy drugs are injected into the cerebrospinal fluid) or with intraventricular chemotherapy (given through a special small device called an Ommaya reservoirOmmaya reservoirA device surgically implanted beneath the scalp that is used to deliver chemotherapy drugs directly into the cerebrospinal fluid (CSF) around the brain and spinal cord.) when lymphoma cells are present in the cerebrospinal fluid (CSF). Whether or not intrathecal or intraventricular chemotherapy is used can also depend on the dose of methotrexate that has been given.
Chemotherapy by itself may be used for elderly people with PCNSL.
External beam radiation therapy may also be offered for PCNSL. Radiation therapy is given to the entire brain (whole-brain radiation therapy or WBRT). Radiation therapy may be given on its own or with chemotherapy. When radiation therapy is given with chemotherapy, it is usually given after chemotherapy treatment. The doses of radiation therapy and chemotherapy may need to be adjusted if both treatments are used.
The combination of radiation therapy and chemotherapy can cause severe damage to the nervous system (neurotoxicity), especially in older people with PCNSL. This can result in changes in cognitive functioning, dementia, behaviour changes, balance and coordination problems and other neurologic problems.
Radiation therapy to the eyes is given for people with ocular lymphoma.
Surgery does not play a role in the treatment of PCNSL because the tumours are often spread throughout the brain and located deep within the brain. A stereotactic biopsystereotactic biopsyA procedure that uses a 3-dimensional scanning machine ( ultrasound, CT scan or MRI) to find the precise location of a tumour and remove a sample for examination under a microscope. may be done to make a diagnosis.
The treatment for recurrent PCNSL depends on the location of the relapse and past treatment. If the person did not receive whole-brain radiation therapy as part of their initial treatment, it may be given for the relapse. Chemotherapy may also be used even if it had been given before, but different drugs may be tried.
People with AIDS-related PCNSL are treated the same way as people who have a normal immune system, but the treatment is more toxic and can be less effective. AIDS-related PCNSL is often treated with:
Chemotherapy may be given to certain people depending on the status of their immune system.
People who have had organ transplants may need to have their immunosuppressant drug dose decreased or stopped.
For more detailed information on specific drugs, go to sources of drug information.