As is the case with many cancers, the treatment options for CNS lymphoma have become much more effective than they were in the past. The first treatment to show promise in patients was radiation therapy. Radiation alone eliminated tumors in almost all patients and forced the cancer into remission, but the cancer almost always returned quickly and the average life expectancy was only about 18 months. I’m hoping for more time than that. Radiation therapy in the past also caused significant damage to healthy tissue and often left permanent loss of cognitive function.
The discovery of the role of chemotherapy in treatment improved patients’ life expectancy to about 48 months when chemotherapy was used in conjunction with radiation. Still a bit short for my tastes. Many chemotherapy drugs are not effective against brain tumors, because the body’s natural defense mechanisms prevent the toxic drugs from reaching the brain. In order to breach the body’s defenses, CNS lymphoma patients receive methotrexate in very high doses, doses large enough to kill the patient. After the drug has had time to attack the cancer cells, the patient receives the anti-dote; the regimen is called “high dose methotrexate with luecovorin rescue.” Most doctors believe that chemotherapy and radiation are most effective if the chemo treatment begins first, followed by the radiation, although it’s not clear why.
Dexamethasone is a powerful synthetic steroid that serves multiple functions in treatment – it kills cancer cells, it lessens the side effects of other chemotherapy drugs, and it reduces swelling in the brain. It’s the same drug that mountain climbers receive to treat high altitude cerebral edema.
Rituximab is a monoclonal antibody, a drug that is designed to attack only a specific type of cell, in this case “B” cells, a type of white blood cell. It’s made by fusing cells from humans with cells from mice.
Another advance in treatment is the use of intrathecal chemotherapy as prophylaxes – that is, the administration of chemo drugs to patients already in remission to prevent recurrence. These drugs are injected directly into the spinal fluid.
The final option, and the only one I have not yet had, is a stem cell transplant. This involves the injection of stem cells from a healthy donor into the patient in order to allow the patient to produce more healthy white blood cells.
Because all these tools are now available to doctors, people (like me) are surviving a disease that was previously a death sentence. Hopefully new discoveries will allow more people to recover from this cancer and all cancers in our lifetimes. If you have the means to do so, please consider making a donation to fund cancer research. Developments in the treatment of one disease often prove useful in treating other ailments, so you never know whose life the research may save.