Malignant brain tumors are usually treated by surgery, chemotherapy, radiation therapy, or a combination of the three. In particular, radiation therapy utilizes x-rays or radioactive material to kill the cancer cells while minimizing the effects to healthy, non-cancerous tissue. The utilization of all types of radiation therapy results in some excess radiation exposure to healthy cells. Due to this overexposure, patients will often experience side effects associated with brain cancer radiation therapy.
Function
Radiation therapy works by focusing a radiation source, like high energy x-rays or radioactive barium, onto the tumor area. Radiation is emitted and travels completely through all of the tissues, both healthy and malignant. When radiation enters a cell, it causes a large concentration of damaging free radicals to form. These free radicals then attack the DNA of the cells, causing the DNA strands to break apart into little pieces. Cancer cells lack the ability to repair the DNA and eventually die, or the growth is slowed down. As effective as this method can be in treating some types of brain cancer, patients receiving radiation therapy will most likely experience moderate-to-severe side effects.
Types
All types of radiation therapy are known to cause both early and late side effects even though the procedure itself is virtually painless. Early side effects include those that are experienced within the first days or weeks after radiation treatments. These side effects are typically mild-to-moderate including soreness and brain swelling, headaches, itchy and irritated skin, hair loss on the treated area, nausea, vomiting, and diarrhea. Late side effects are experienced several months or even years after the treatment and may include alterations in mental function, like memory loss or speech difficulties. There is also higher risk for developing a secondary cancer, although this may be independent of the radiation therapy.
Benefits
Radiation therapy for brain cancer, when combined with other treatments, has the potential to completely destroy the cancer and reduce the possibility of recurrence. However, one must always weigh the benefits with the potential side effects associated with treatment. Besides the mild side effects, one main cause for concern is the potential for the radiation to cause cancer itself. According to the National Institutes of Health, only 5 percent of those who receive radiation therapy develop a secondary cancer that can be directly linked to therapy. Because of this low occurrence, they suggest that the benefits associated with radiation therapy far outweigh the risks.
Misconceptions
Contrary to some beliefs, those who undergo radiation therapy for brain cancer will not be radioactive following the treatment. Once the machine has been turned off, the radioactivity is halted. Radioactivity does not circulate through the bloodstream like chemotherapy. However, those who receive brachytherapy, or internal radiotherapy, may be radioactive because the radioactive substance is actually implanted within the body next to the tumor. A patient who receives this type of therapy will be radioactive until the implant has been removed or the radioactivity has decayed to harmless levels.
Considerations
While side effects associated with brain cancer radiation therapy have been well established, those who enter clinical trials may experience new side effects. Clinical trials are new treatment strategies that are being tested by physicians and researchers, and depending upon the stage of the trial, side effects may not be known.
