Central nervous system (CNS) lymphoma is a cancer that affects the lymphatic system in the brain or spinal cord. CNS is an aggressive lymphoma, which affects survival rates.

CNS lymphoma is a rare form of non-Hodgkin lymphoma. Non-Hodgkin lymphoma is a type of cancer that affects the lymph system, a part of the immune system. CNS lymphoma begins in immune cells called lymphocytes and weakens the body’s defenses against pathogens.

This article looks at CNS lymphoma in more detail, including the causes and symptoms. It then discusses how doctors diagnose and treat the disease.

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CNS lymphoma is a type of non-Hodgkin lymphoma. In this condition, cancer cells form in the lymph tissue in the brain or spinal cord. Secondary CNS lymphoma can also happen if cancer cells from other parts of the body spread to the brain or spinal cord.

Non-Hodgkin lymphoma develops in white blood cells called lymphocytes. In about 95% of cases, CNS lymphoma affects the B lymphocytes, which are cells that make antibodies.

In the remaining cases, CNS lymphoma affects T lymphocytes. These cells help fight infection by activating other cells, destroying germs, or slowing the growth of dangerous invasive pathogens.

CNS lymphoma is more aggressive than other forms of lymphoma, with a 5-year survival rate of 30%. In people who go into remission, the cancer often recurs, helping explain the low survival rate.

Without any treatment, the average survival length after diagnosis is 1.5 months. With treatment, though, people can live longer or even recover. Overall, treatment will lead to long-term survival in 15–20% of people with CNS lymphoma.

Newer treatments have prolonged survival. For example, research has shown that the median overall survival with high dose methotrexate is 25–55 months. However, some people live much longer, and doctors cannot predict how long someone will live or whether the cancer will recur.

The outlook for people with CNS lymphoma varies among individuals. Factors that reduce the chance of a positive outlook include:

  • having HIV or another condition that weakens the immune system
  • being over the age of 60 years
  • having poor overall health

Lymphoma develops when immune system cells divide out of control. Scientists do not fully understand why some types of lymphoma enter the CNS or why some people develop lymphoma.

Some risk factors that may increase the chances of developing non-Hodgkin lymphoma, including CNS lymphoma, include:

  • Weak immune system: Lymphoma is more common among people with HIV and those with a weakened immune system. In people with lymphoma, HIV may also be a risk factor for the disease spreading to the CNS.
  • Infections: Infections with certain viruses, such as the Epstein-Barr virus, herpes simplex virus, and human T-cell lymphotropic virus, may increase the risk of lymphoma by changing the immune system. Additionally, infections that stimulate the immune system for a long time may increase the risk.
  • Autoimmune diseases: Rheumatoid arthritis, lupus, and some other autoimmune diseases may increase CNS lymphoma risk.
  • Radiation: Exposure to radiation from atomic bombs, nuclear accidents, and prior cancer treatment may affect risk.
  • Age: People over the age of 60 years are more vulnerable to lymphoma, though this cancer can also affect younger people.
  • Genetics and family history: People with a close relative who has had lymphoma, such as a parent or sibling, have a higher risk.
  • Chemical exposure: Certain chemicals, including herbicides, benzene, and some cancer drugs, may increase the risk.
  • Race: In the United States, white people are more vulnerable to lymphoma than African American and Asian American people.

People with CNS lymphoma may not have any symptoms, or the symptoms might appear slowly. People who have symptoms may notice neurological changes, such as:

  • unexplained vomiting and nausea
  • seizures
  • trouble thinking clearly or paying attention
  • vision changes, such as double vision
  • weakness in the arms or legs
  • tingling or other strange sensations in the body
  • headaches
  • sudden hearing issues, including unexplained hearing loss

Doctors use a combination of tests to diagnose CNS lymphoma. These may include:

  • Physical exam and health history: A doctor will ask about a person’s symptoms and family medical history. They might also perform a neurological exam to look for signs of CNS lymphoma, such as changes in the reflexes or a history of seizures.
  • Eye exam: A doctor may dilate the pupils and look through the eye with special equipment to check for signs of cancer or tumors. In some cases, they may repeat this exam to track changes or measure tumor growth.
  • MRI: This test uses magnets to view blood flow in the brain. A doctor usually injects a dye into a vein to get better visibility of parts of the brain and look for cancer cells.
  • Lumbar puncture: This procedure involves the insertion of a needle into the spine to withdraw cerebrospinal fluid, the fluid in the spinal cord. The fluid may contain tumor cells or have abnormal protein or glucose levels.
  • Biopsy: For a biopsy, a doctor takes a sample of a suspected tumor that lab technicians will then check for cancerous cells.
  • Blood work: A doctor may perform a complete blood count to look for abnormalities in the immune system. They may also check for HIV, which is a risk factor for lymphoma.

Unlike other forms of lymphoma, which doctors stage according to how much and how far they have spread, there is no standard staging system for CNS lymphoma. Instead, doctors look at various factors, such as the location of cancer in the body and a person’s overall health, to help them determine the best treatment plan.

Doctors also assess whether the lymphoma is primary or secondary. Primary CNS lymphoma refers to lymphoma that initially appeared in the brain or spinal cord. Secondary means that the lymphoma has spread to the CNS from other parts of the body.

Certain disease markers, including elevated levels of protein or lactate dehydrogenase in the cerebrospinal fluid, can affect a person’s outlook after diagnosis.

The right treatment depends on many factors, including the location of the cancer and the person’s overall health and treatment goals. The main treatment options include:

  • Radiation: Radiation uses high energy rays to destroy or shrink cancer cells. However, there is a risk of neurological damage, so a doctor may recommend different or additional treatments.
  • Medications: Certain medications, such as methotrexate, may improve survival time.
  • Chemotherapy: A doctor may recommend a regimen of anticancer drugs that target fast-growing cancer cells. They may use chemotherapy, either instead of or in addition to other treatments.
  • Steroids: Steroids may help with some cancer side effects, such as vision issues.

About half of people with CNS lymphoma will experience a return of the cancer, usually within 5–10 years. When this cancer returns, the average overall survival is 2 months.

CNS lymphoma is an aggressive cancer that affects the brain or spinal cord.

Treatment options are improving rapidly, and the survival time is steadily improving. Prompt, aggressive treatment can prolong a person’s life and may cure the cancer.

Anyone who is experiencing unexplained neurological symptoms should see a doctor as soon as possible to rule out this condition.