Understanding Your Choices
What are the differences between radiation systems?
There are four external-beam radiation systems that doctors can use to treat your cancer. The first three of these have been used successfully to treat head and neck cancer for a number of years.
- The oldest system is called Two-Dimensional Radiation Therapy or 2DRT. This system targets the tumor using a two-dimensional image, much like a picture or photograph. The beams can only be aimed at a few angles and do not change strength while they are being given. 2DRT is not used as often as the newer systems.
- A newer system is called Three-Dimensional Conformal Radiation Therapy or 3DCRT. This system uses three-dimensional images that let doctors better target the tumor. The images are made with a computed tomography (CT) or magnetic resonance imaging (MRI) machine. The beams can be aimed at more angles than 2DRT to limit the amount of radiation to the normal areas around the tumor.
- A more recent system is called Intensity-Modulated Radiation Therapy or IMRT. This system is similar to 3DCRT, but the doctor can adjust the amount of radiation you get from each beam. This is done to try to reduce injury to the healthy areas around the tumor.
- Another system uses a different kind of energy beam to treat your tumor. This system is called Proton-Beam Radiation Therapy or PBRT. There is very little information about how well this form of radiation therapy works, and it is not widely used.
Which type of radiation therapy is most effective for my cancer?
- Doctors do not know if one type of radiation therapy is more effective than others in stopping or slowing down the growth of your head and neck cancer.
- Doctors do not know if any one type of radiation therapy will control your cancer better or help you live longer.
Which type may have fewer side effects?
- There is some evidence that IMRT causes less damage to the glands that make your saliva (the fluid or spit in your mouth) when compared to 2DRT or 3DCRT. Early results from a recent study suggest that when patients were examined 1 year after treatment, those who were treated with IMRT experienced dry mouth (xerostomia) less often than those who were treated with 2DRT or 3DCRT.
- While doctors think that IMRT may help avoid damage to other normal organs in the head and neck—such as your eyes, brain, and other glands—they do not know this for sure.
- The skill and experience of your doctors in using each type of radiation therapy may be important. The current studies were conducted in centers associated with universities and medical schools. Doctors do not know if the results are different in other types of medical centers.
- Doctors do not know how the side effects of PBRT compare to the other three types of radiation therapy.
Making a decision
What questions should I ask my doctor?
- What side effects of radiation therapy am I most likely to have, when might they occur, and how long might they last?
- Which forms of radiation therapy are available to me?
- How much experience do the doctors and medical staff here have with each form of radiation therapy?
- How do you make sure that the tumor and the tissues around it get the right amount of radiation?