Important Questions About Radiation Therapy

Radiation therapy is one of the most commonly used treatment options for prostate cancer. For early stage prostate cancer, surgery and radiation therapy are the two primary treatment options. For men who have undergone surgery to remove their prostate, but are found to have residual prostate cancer in the pelvis, radiation therapy can be used to treat this residual tissue.

What Is External Beam Radiation Therapy?

Radiation therapy can be administered from inside or outside the body.

• Brachytherapy is radiation therapy that is administered using small radioactive implants or seeds within the body.
• External beam radiation therapy involves the use of radioactive sources located outside of the body.

What Happens During the Administration of Radiation Therapy?

You will need to change into a hospital gown. Then, a radiation technologist will help you onto a table where you will need to lay on your back throughout the treatment session. It’s important to lay very still throughout the treatment session so that the radiation is delivered only to the area intended. Your radiation oncologist and a physicist have worked together to accurately target your radiation to just the right places in your body. This is done in order to minimize damage to the nearby normal tissues of your body while maximizing the damage to the tumor and immediately nearby tissue.

While you lay on the table, a radiation machine rotates around you. This radiation machine acts to direct a beam of invisible radiation at the part of your body that needs treatment (in this case, the prostate and any nearby structures that your doctor has determined should be treated). The machine will not touch you during the therapy. While the radiation is being delivered, you will not feel pain; it's likely that you will not feel anything at all. The machine may be noisy, however, so expect this before going for your treatment.

How Often Will I Go for External Beam Radiation Therapy?

External beam radiation therapy is usually administered on a once-daily basis, Monday through Friday, for a number of weeks (up to 10, depending on the goal of your radiation therapy). Some radiation oncologists prefer to deliver the radiation on a slightly different schedule than this and will give you their preferred method upfront. Sometimes more than one treatment in a day is given. Sometimes treatment is given on weekends.

How Much of My Body Will Be Treated?

The newer external beam radiation therapy machines have the capability to deliver radiation to a very precise area in your body. For instance, if the prostate is the only area that needs to be treated with radiation, then the machine can be programmed to deliver radiation essentially to only the prostate. Because the radiation beam must pass through the outside of your body to reach the inside (where your prostate is), it is necessary that a tiny amount of radiation passes through a given area of your skin. Often multiple tiny beams of radiation from hundreds of directions are targeted on the prostate, thus lowering the actual power of each beam without taking away from the total energy deposited in the prostate.

Because the radiation beams are passing through your skin and other tissues before converging on the prostate, these tissues will also receive a tiny dose of radiation. With external beam radiation, there is no way to completely eliminate radiation to the skin and underlying tissues, but the radiation can be minimized by a number of techniques that your radiation oncologist can implement.

How Do I Plan for External Beam Radiation?

Before you go for your first treatment, you will have a meeting with your radiation oncologist so that he or she can describe the course of treatment, address any questions you may have, go over your complete medical history and perform a physical exam.

After your initial meeting, you will then go for a radiation treatment planning session where you will have a CT scan to determine exactly where in the body the radiation will be administered. Tiny tattoos are then placed on your skin to permanently mark the borders of the treatment field. These tattoos are permanent, but very tiny.