Central nervous system (CNS) lymphoma is a malignant growth, or neoplasm, that originates in the white blood cells of the lymphatic fluid in the brain and spinal cord.
Description
CNS lymphoma affects the brain and the spinal cord, the two components of the CNS. The brain and spinal cord work together to control, monitor, and interpret all the physical and mental processes of the body. They make possible the activities a person takes for granted, such as walking, talking, thinking and remembering. A malignancy, or neoplasm, in the brain or spinal cord interferes with the normal functions of the body.
An uncontrolled growth of cells called lymphocytes causes lymphoma. Lymphocytes are the white blood cells in the lymphatic system. Under normal conditions they help the body resist invasion by foreign substances and organisms. In other words, they assist with immune response or defense.
When the uncontrolled growth of lymphocytes originates in the brain or spinal cord, it is called primary CNS lymphoma, or simply, CNS lymphoma. The specific place of origin of CNS lymphoma is probably in cells known as B cells. Other kinds of lymphoma begin elsewhere in the lymphatic system. They may also eventually affect the brain and spinal cord, but they are not called CNS lymphoma.
In most cases, CNS lymphoma does not produce a defined and specific site of growth, or a tumor. Generally, the cancer cells spread throughout the brain and spinal cord. The spread gives way to lesions, which are places where tissue breaks down.
Demographics
Although the number of cases is on the increase, CNS lymphoma is rare. Between 1 and 2% of all uncontrolled growths in the brain result from CNS lymphoma. The most common age of diagnosis in the general population is between 52 and 55 years. However, in patients that have experienced immune system problems, age at diagnosis is much younger, at about 34 years.
Events and conditions that affect the immune system put a person at greater risk for CNS lymphoma. For example, someone who has had an organ transplant is
more vulnerable to the disease. Part of the reason is that transplant patients are given drugs to suppress, or reduce, the action of the immune system so their bodies will accept an organ from a donor. Individuals with acquired immunodeficiency syndrome (AIDS) are also at higher risk for CNS lymphoma.
Causes and symptoms
The cause of CNS lymphoma is not known. It is more common in individuals with suppressed immune systems, and individuals with some conditions linked to the X chromosome, one of the two sex chromosomes, seem to be at higher risk. Studies indicate that exposure to certain herbicides also increases risk.
One role of the lymphatic system is to collect fluid that builds up outside cells and to return it to blood vessels. CNS lymphoma obstructs this process. Fluid builds up in the body and puts particular pressure on the cranial nerves, the nerves that carry information directly from the brain to organs such as the eyes and ears. Consequently, symptoms of CNS lymphoma often occur in the organs of the head and in the face.
Symptoms cause a person to consult a physician. The initial assessment is made using computed tomography (CT) or magnetic resonance imaging (MRI). To confirm a diagnosis a physician does a variety of tests. They include a physical examination of lymph nodes, chest x ray, blood and urine tests, eye exam, bone marrow biopsy, and—in males—an ultrasound of the testes. Some of the tests are done to rule out other kinds of lymphoma.
Treatment team
CNS lymphoma requires attention from several different types of physician specialists. A neurologist—a physician specializing in the nervous system—does the initial assessment. A radiologist interprets x rays, CT scans, and MRI images. A hematologist or oncologist
evaluates the results of blood tests. A pathologist studies the tissue from a biopsy. If there is surgery, and in many cases there is not, the surgery team that removes the tumor typically includes a neurosurgeon and an orthopedic surgeon. The orthopedic surgeon takes part because it is necessary to cut through bone to reach the brain, and maneuver around vertebrae to reach the spinal cord. At premier cancer centers, teams of physicians work collaboratively, with one person (usually an oncologist) taking the lead. Physical and occupational therapists who help with rehabilitation following treatment and surgery, and registered nurses who administer chemotherapy, are also part of the team.
Clinical staging, treatments, and prognosis
All treatment is palliative (designed to provide relief from symptoms and make a patient comfortable). Surgery is sometimes used to eliminate well-defined masses that are causing pressure in the brain and spinal cord. This pressure causes the symptoms, such as headache and numbness, because it contributes to swelling and dislocation. However, because CNS lymphoma
generally spreads throughout the brain and spinal cord, surgery is usually not a treatment choice.
Medication in the form of steroids and radiation treatment both give good results over the short term by causing clusters of malignant cells to shrink briefly. However, neither treatment is effective for much more than six months. A great deal of interest surrounds research aimed at finding chemotherapy that works effectively for this type of cancer. Chemotherapy for CNS lymphoma is sometimes given by putting drugs directly into the brain or spinal cord.
The prognosis (outlook for recovery) for a patient with CNS lymphoma is poor. Untreated, the disease usually results in death in just a few weeks. If it is treated, life can be extended by perhaps six months to one year, and occasionally longer.
Ulrich Herrlinger, M.D., and colleagues in Tuebingen, Germany, have reported that the combination of radiation therapy and chemotherapy gives patients a much better chance of extended survival, prolonging life for more than six years in one individual. Eleven of the 21 patients in their study lived for 33 months or longer.
Alternative and complementary therapies
Any relaxation program, such as biofeedback or yoga, often help a patient deal with the poor prognosis, pain, and symptoms of CNS lymphoma.
Coping with cancer treatment
Radiation therapy, particularly of the entire brain that is required to treat most CNS lymphoma, can greatly alter memory and thought processes. Being prepared for the effects of radiation before the treatment begins is important. For example, a patient can write out a daily schedule of things to do—the essentials of an ordinary day such as brushing teeth and combing hair. This schedule can then be used as a memory aid after treatment.
Having a patient taking an active part in planning the course of treatment can be helpful, such as participating in meetings with the treatment team. Premier cancer treatment centers encourage patients to be an integral member of the team. Because some individuals beat the odds and live much longer than expected, an optimistic attitude is important.
Clinical trials
The National Cancer Institute at the National Institutes of Health, Bethesda, MD, offers a Cancer Information Service that can connect people with clinical trials. The toll free number for the Service is 1-800-4-CANCER(1-800-422-6237).
Prevention
No prevention is known; however, any effort that reduces the number of people infected with the virus that causes AIDS will indirectly reduce the number of people with CNS lymphoma. Three percent of all AIDS patients exhibit CNS lymphoma.
Special concerns
Because CNS lymphoma is a fatal disease, patients must make decisions about end-of-life care. How will it be arranged: at home, in a hospice, in some other setting? Who will make decisions if the patient is no longer able to state his or her desires? Advance directives, or written instructions for how a person wishes the medical team to respond at each juncture of the illness, should be completed as soon as possible after a diagnosis is made.
Resources
BOOKS
Canellos, George P., et al. The Lymphomas. Philadelphia: W.B.Saunders Co., 1997.
PERIODICALS
Herrlinger, Ulrich, et al. "Primary Central Nervous System Lymphoma" Cancer 91 (Jan.1, 2001): 131-135.
—Cell in the lymph system that produces antibodies, which protect against foreign substances.
Biopsy
—Tissue sample taken from the body for microscopic examination.
Computed tomography (CT)
—X rays are aimed at sections of the body (by rotating equipment) and images appear as slices. Results are assembled with a computer to give a three-dimensional picture of a structure within the body.
Herbicide
—A chemical compound used to kill plants.
Lymphatic system
—The nodes of tissue and the fluid that moves among them. This system works to protect the body from invading substances and organisms, and to return fluid that collects outside cells to the blood vessels.
Magnetic resonance imaging (MRI)
—Magnetic fields and radio frequency waves take pictures (images) of the inside of the body.
Ultrasound
—Sound waves are bounced off structures in the body to produce an image of those structures.
QUESTIONS TO ASK THE DOCTOR
Will my quality of life be better with or without radiation treatment? How much of the time that I gain from radiation treatment will be time that I can function and do some of the things I enjoy?
Is there a clinical trial in which I could participate?
Is there a support group for CNS lymphoma at this institution or in this town?
