Johns Hopkins Health Alert
What You Should Know About External Beam Radiation Therapy
External beam radiation therapy (EBRT) for prostate cancer involves aiming beams of radiation at the prostate from outside the body. External beam radiation therapy is a treatment option for men with localized prostate cancer (stage T1 and T2) or locally advanced disease (stage T3). Although no randomized trial has directly compared radical prostatectomy and external beam radiation therapy, available evidence suggests that for patients with cancer confined to the prostate, either approach offers a good chance of being cancer free five to 10 years after treatment.
Radiation oncologists have made a number of refinements in external beam radiation therapy in an attempt to increase cure rates and reduce the risk of complications. These refinements include three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT) and proton-beam radiation.
- 3DCRT. In 3DCRT, the radiation oncologist relies on dozens of CT scans to target the radiation precisely to the tumor. This allows higher doses of radiation to be delivered (potentially increasing the treatment's effectiveness) and causes less damage to healthy tissue (potentially reducing the severity of treatment side effects).
- IMRT. IMRT is a refinement of 3DCRT. Relying on computer software to determine the orientation, number and intensity of the radiation beams, IMRT is even more precise than 3DCRT.
- Proton-beam radiation therapy. Proton-beam radiation therapy is delivered in the same manner as 3DCRT but uses positively charged subatomic particles (protons) instead of X-rays to kill cancer cells. The potential advantage of the technique is that protons cause minimal damage to the tissues they pass through on their way to the cancer cells. The hope is that proton-beam radiation therapy will allow higher doses of radiation with fewer side effects.
Complications. The complications of external beam radiation therapy are primarily adverse effects on the urinary tract and bowel. However, these effects usually disappear days to weeks after treatment is completed. The risk of long-term urinary complications, such as blood in the urine, bladder problems or narrowing of the urethra, is about 8 percent. The risk of long-term rectal complications, such as rectal inflammation (proctitis), bleeding, ulceration, narrowing and chronic diarrhea, is about 3 percent.
With external beam radiation therapy, the risk of erectile dysfunction becomes more likely with time. In an analysis from the Prostate Cancer Outcomes study, 63 percent of men treated with radiotherapy had erectile dysfunction five years after the procedure. Younger men and those with normal sexual function before external beam radiation therapy are the most likely to maintain potency, just as with surgery.
Posted in Prostate Disorders on October 5, 2011
Medical Disclaimer: This information is not intended to substitute for the advice of a physician. Click here for additional information: Johns Hopkins Health Alerts Disclaimer
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How does CyberKnife Robotic Radiosurgery compare to other forms of radiation therapy?
Posted by: JSW | October 5, 2011 2:39 PM