Both external and internal radiation therapy may be used to treat prostate cancer.
External Beam Radiation Therapy
External beam radiation therapy uses radiation produced by a machine called a linear accelerator. Short bursts of x-rays are fired from the machine at the tumor. The x-rays come out in square shapes; the radiation oncologist designs special blocks or special collimators within the machine to shape the radiation beam so that it treats the cancer and as little normal tissue as possible.
There are several newer techniques that may be used in treating your prostate cancer, including conformal treatment planning and intensity modulated therapy (IMRT). These techniques allow a more precise delivery of radiation to the tumor area and may be used alone or in combination with surgery, hormonal therapy, or brachytherapy (implantation).
The side effects of radiation result from injury to the normal tissues. There are many new ways that a radiation oncologist can customize your treatment to try to kill as much cancer while sparing as much normal tissue as possible.
The radiation oncologist will determine how many treatments you will receive. Treatment generally only takes a few minutes, and the total treatment time can range from 5-8 weeks depending on the total dose required.
Radiation therapy can be given to treat cancer at its initial site or once it has spread. In some cases, once cancer has spread, radiation is no longer curative. However, the treatments can help resolve problems that the cancer may be causing, including pain and weakness.
Can you continue to receive radiation to an area that has already undergone radiation treatment? While it is true that each tissue in the body can only safely tolerate a certain dose of radiation, radiation therapy is very focused. Therefore, it is possible to receive additional treatments to an already treated area. Your radiation oncologist is the best source of information as to what dose you can safely receive.
Internal Radiation Therapy
Internal radiation therapy, also called brachytherapy, places the radiation source as close as possible to the cancer cells. To treat prostate cancer, a capsule containing radioactive materials is placed directly into the prostate.
Some implants are left in place permanently, while others are left in place for only 1-3 days. Depending on which type of implant you receive, you may stay in the hospital while the implants are in place. Sometimes implant/internal radiation is combined with external beam radiation therapy.
Brachytherapy requires a short hospital stay and, because of the radioactivity emitted by the capsule, may require some modifications in lifestyle for a period of time after the procedure.
Research continues to show that brachytherapy is equivalent to external beam radiation therapy or surgery in the treatment and cure of prostate cancer. However, the practice of brachytherapy, like surgery, is dependent on who is doing the procedure. Some doctors who perform brachytherapy procedures participate in quality control programs that monitor their practices and help improve their results.
Radiation therapy for prostate cancer may cause erectile dysfunction (ED), and urinary and bowel problems. Most studies show that ED rates are less for radiation therapy than for standard prostatectomy and slightly less than that for nerve-sparing procedures. Rates of incontinence following radiation therapy are also less than following prostatectomy. But, there is an increased risk of cystitis due to radiation.
Treatments are available to help manage these side effects. Sometimes adjustments to treatment doses may also be possible. The earlier side effects are addressed, the more likely they will be controlled with a minimum of discomfort.
- Reviewer: Mohei Abouzied, MD, FACP
- Review Date: 09/2016 -
- Update Date: 09/17/2014 -