Slowing the growth and stopping the spread of cancer cells.
Radiation therapy (also called radiotherapy) is a treatment for cancer that uses high doses of radiation to kill cancer cells and stop them from spreading. Low doses of radiation are used in common activities such as X-rays of your teeth or bones, yet when given in high doses, radiation kills or slows the growth of cancer cells.
Radiation therapy may be used at different times during your cancer treatment and for different reasons:
- Before surgery, to shrink a cancerous tumor (neoadjuvant therapy)
- After surgery, to stop the growth of any remaining cancer cells (adjuvant therapy)
- In combination with other treatments, such as chemotherapy, to destroy cancer cells
- In advanced cancer to alleviate symptoms caused by the cancer
Radiation is delivered differently depending on the nature of the cancer. It can be delivered by an external beam using a linear accelerator (linac) or internally, where a source of radiation is placed inside the body (often called brachytherapy).
External Beam Radiation Therapy
Radiation therapy is a well-proven treatment for cancer and new advances have made it safer and more effective than ever. External beam radiation therapy comes from a linear accelerator that aims radiation at your cancer. Most people get external beam radiation therapy once a day, five days a week, Monday through Friday. Treatment lasts for two to 10 weeks, depending on the type of cancer you have and the goal of your treatment. The time between your first and last radiation therapy sessions is called a course of treatment. Radiation may also be given in smaller doses twice a day (hyperfractionated radiation therapy).
You should know:
- About 60 percent of people with cancer receive radiation therapy.
- Radiation therapy does not hurt while it is being given.
- Radiation therapy may be used alone or in conjunction with other forms of treatment.
- Hair loss generally only occurs at the site of the radiation therapy and is usually temporary.
Types of Radiation Therapy
Image-Guided Radiation Therapy (IGRT)Image-guided radiation therapy is a technology advancement that enables the use of frequent imaging during a course of radiation therapy to support precision and accuracy in areas prone to movement, such as lungs and prostate gland, as well as for tumors located close to critical organs and tissues.
Intensity-Modulated Radiation Therapy (IMRT)Intensity-modulated radiation therapy is an advanced mode of radiotherapy that allows computer-controlled radiation intensity to be changed (modulated) during treatment to support three-dimensional treatment precision and accuracy.
Volumetric Modulated Arc Therapy (VMAT)The Elekta Volumetric Modulated Arc Therapy (VMAT) is a radiation therapy technique that allows clinicians to deliver more tightly focused treatments to tumors in a significantly shorter time. Using the sophisticated treatment plan, Elekta VMAT delivers a continuous beam of radiation while the linear accelerator rotates around the patient as opposed to other radiation treatment systems that require the linear accelerator to deliver a small amount of radiation, and then stop to rotate to a new position. The Elekta VMAT enables the radiation to remain on while the linear accelerator movements occur, resulting in treatments that can be shorter and more closely focused on the tumor.
In addition to reducing treatments which usually take 15 minutes to five minutes, this advanced therapy technique significantly improves the treatment experience by allowing physicians to plan a treatment that is more accurate to the shape and size of the tumor, which spares surrounding healthy tissue and reduces unwanted radiation to organs and nearby critical structures.
Many cancer types can benefit from VMAT treatments, but it is typically used for prostate, lung, head and neck cancers.
Radiation Therapy Treatment Procedure
PlanningYour treatment begins with the planning stage. Before planning your treatment, the radiation oncologist may ask for some diagnostic procedures and imaging to be done. During the planning session with the radiation oncologist and radiation therapist, you will be asked to lie very still while X-rays or scans are taken to define the treatment area. The doctor will use these to make a treatment plan for you.
The treatment plan is created using special software that calculates the beam angles and radiation dose needed for the most effective treatment. Each treatment plan is unique based upon the type, size and location of your cancer.
The total dose of radiation needed to treat the cancer is carefully calculated. The total dose is then divided into many ‘fractions’ which are delivered as your radiation therapy plan – usually short sessions of radiotherapy treatment on most days each week, for several weeks.
Treatment sessions continue until you have had the total dose of radiation. By having a small fraction of the total dose on many sessions, it is more likely to work better than having the whole dose at one session and it also reduces the severity of side effects.
PreparationLike planning, you will only need to go through preparation one time. In order to ensure that the radiation hits the selected target with absolute precision you need to be positioned in a secure and comfortable way on the treatment table. There are different types of frames and devices that can be used to help you get into the correct position and hold completely still during the treatment.
The radiation therapist may put tattoos or dots of colored ink on your skin to mark the treatment area, then use them each day to make sure you are in the correct position.
TreamentWhen you begin your treatment program, you will take your place in the fixation device that has been selected and customized for you. Data from the planning and imaging sessions is used to make sure you are in the correct position, and imaging may take place to confirm placement and target information.
When all is ready, the treatment will begin as the linac begins to rotate around you. The movement may be continuous or step by step. The radiation itself is invisible and painless, and you will be fully awake.
One or more members of your treatment team will monitor everything from outside the treatment room. You can easily communicate with them via intercom, and you have the ability to release your fixation at any time if necessary.
Each session of treatment usually only lasts a few minutes (although it may take several minutes to position you and the machine correctly each time). By emitting the treatment in short bursts from different angles, each burst will pass through different parts of your body on the way to the target. This helps to reduce damage to normal tissues.
Follow UpMost patients attend follow-up clinics following their course of radiation therapy treatments, typically for up to five years. These are held to help manage any post-treatment side effects and to monitor the disease regression or progression.
Always consult your doctor or a member of your medical team if you have any questions.
Possible Side-Effects of Radiation Therapy
Side effects can occur with radiation therapy because the high doses of radiation used to kill cancer cells may have also damaged healthy cells in the treatment area. Side effects are different for each person, with some people having more and others barely noticing any. Side effects may be more severe if you also receive chemotherapy to treat your cancer.
Most side effects occur gradually, usually beginning to appear by the second or third week into treatment. They are temporary, but some may continue for weeks or months after your treatment before they subside. Talk to your radiation therapy team about your chances of having side effects and let them know if you have any problems.
Many people who get radiation therapy have skin changes and some fatigue. Other side effects depend on the part of your body being treated and may disappear after about two months of the completion of your treatment.
During radiation therapy, your body will use up more energy than it normally does, causing feelings of fatigue. Additionally, the stress of coping with a serious illness, trips for treatment and the effects of radiation on the body all can cause fatigue. It is common for fatigue to last for 4-6 weeks after your treatment has been completed, after which it will begin to improve.
Skin changes may include dryness, itching, peeling, or blistering. These changes, which are generally temporary, occur because radiation therapy damages healthy skin cells in the treatment area. You will need to take special care of your skin during radiation therapy.