By Dr. Mukul Roy, Oncology
Radiation therapy is used for destroying the brain tumor cells, and relieves the symptoms of discomfort and pain caused by the tumor. Radiation is usually used after biopsy or resection of the tumor. This is done to destroy the microscopic cells of the tumor which have been left behind. Sometimes this is also an option for unresectable brain tumors or the metastatic tumors which spread to the brain from other parts of the body.
The radiation therapy is planned on several factors like the size and type of the tumor and the extent to which it has spread. Usually external beam radiation is used for the brain cancer and the area radiated involves the tumor and the surrounding area. In case of a metastatic brain cancer the radiation is given to the entire brain. People who have lung cancer receive radiation in the brain as a preventive therapy in order to stop the metastatic cancer from developing.
Side effects of brain cancer radiation:
Depending on the site, dose, and other factors the radiation therapy when given to the brain might cause side effects. Hair loss, fatigue, edema, skin irritations are a few common side effects of brain tumor radiation. In some cases some people might develop swelling of the ankle, foot, calf and blood clots in the leg.
Radiation therapy is basically the use of targeted energy like X-ray and radioactive substances to kill the cancer cells, or shrink them or change the symptoms related to cancer. This therapy might be used as:
- Primary treatment for the destruction of the cancer cells
- In combination with other ongoing treatments to inhibit the growth of the cancer cells
- Prior to another treatment to shrink the cancer cells
- Post some treatment to stop the growth of any cancer cells that have been left behind
- To relieve cancer symptoms
Types of radiation:
Some of the radiation methods commonly used are:
- External beam radiation therapy: In this the radiation is directed from outside the body on the cancerous cells in the body. Some examples of this are IMRT, TomoTherapy, stereotactic radiosurgery, 3D conformal radiation therapy and IGRT.
- Internal radiation therapy: In this the radioactive substance is placed close to the tumor with the help of a catheter or some carrier. Examples of this are high-dose rate brachytherapy.
- Systemic radiation therapy: In this a radioactive substance is injected or swallowed, which further locates and destroys the cancerous cells. Example of this is radioactive iodine therapy.
- Managing radiation side effects: Radiation therapy in some cases can cause unpleasant side effects like fatigue and nausea. Thus it should be kept in mind that maximum radiation doses should be given with less or little impact on the healthy tissues.