1. Rare Cancer on the Rise
Primary central nervous system lymphoma (PCNS lymphoma) was extremely rare 25 years ago, and it's still uncommon today. However, doctors are seeing a rise in this cancer for several reasons. One of the risk factors for developing PCNS lymphoma is living with a compromised immune system. The advances in treatment for HIV positive patients mean that these immune-compromised patients are living longer, and therefore have more time to develop PCNS lymphoma. Other patients who receive treatments that depress the immune system, such as patients receiving high doses of chemotherapy and radiation in preparation for a bone marrow transplant, are at risk. Finally, the advances in diagnostic techniques means more doctors are able to pinpoint a diagnosis of PCNS lymphoma than before.
2. Making a Diagnosis
Symptoms of PCNS lymphoma can vary, based on the location of the tumors in the brain or spine. Patients should see a neurologist for an evaluation of symptoms that can include headache, dizziness, vomiting, memory problems or paralysis. The doctor can use imaging tests, like X-rays, CAT scans, or MRI's to rule out other diagnoses. The definitive diagnostic test is usually a biopsy, where the doctor removes tissue for examination under a microscope. The doctor may remove cells from the spinal fluid, or by making a cut in the skull to remove a sample of a tumor in the brain.
3. Symptom Relief
Surgery has a limited role in curing PCNS lymphoma but an important role nevertheless. Surgeons may remove most of a tumor pressing on a sensitive area of the brain or spine to reduce symptoms like speech difficulties or paralysis. The surgeon may also insert a shunt into the brain to relieve swelling caused by the accumulation of fluid. The shunt resembles a thin tube through which fluid drains via a valve activated by the presence of excess fluid in the skull.
4. Honing in on Brain Tumors
Doctors may use radiation therapy to treat PCNS lymphoma, which uses high energy X-rays to kill cancer cells. Because of the sensitive nature of the brain and central nervous system, doctors use special ways of administering radiation therapy that limits the damage to healthy tissues. A gamma knife uses a helmet to stabilize the patient's head while an X-ray beam fashioned exactly to the shape of the tumor delivers cancer-killing beams to the brain. Three-dimensional conformal radiation uses a mobile linear accelerator to rotate around the patient's head, aiming X-rays from all sides.
5. State-of-the-art Drugs
Doctors face challenges in using chemotherapy for PCNS lymphoma due to the blood-brain barrier, a natural protective system that keeps toxins from damaging the brain. Methotrexate is one of the most effective chemotherapy drugs for this type of lymphoma. Researchers are conducting clinical trials to find new drugs and better ways of administering standard drugs to diminish side effects and increase the chances of remission.
