Radiation therapy uses high-energy rays or particles to kill cancer cells. Radiation may be used:
Two main types of radiation therapy can be used: external beam radiation and brachytherapy (internal radiation). Both appear to be good methods of treating prostate cancer, although there is more long-term information about the results of treatment with external beam radiation.
External Beam Radiation Therapy (EBRT)
Radiation therapy is a preferred treatment for prostate cancer patients because it targets cancer cells, with less damage to healthy tissues than other treatments. External beam radiation therapy (EBRT) delivers high-energy rays to tumors, using a machine called a linear accelerator. At the Foshay cancer center the Varian Trilogy™ allows prostate cancer radiation therapy to be delivered from any angle and shapes radiation beams to conform to the contour of the tumor.
Our state-of-the-art radiation technology enables our oncologists to more accurately target a tumor with higher doses of radiation, while minimizing damage to your healthy prostate tissue. This helps to lower the risk of side effects typically associated with radiation treatment for prostate cancer, like incontinence and erectile dysfunction.
Our technology allows us to monitor the tumor’s position before each treatment, and track if the tumor has shifted or changed shape since your last treatment. Treatment takes only a few minutes, plus some additional time for set-up.
During treatment you will lie down in the position that was determined during your simulation visit. You may be positioned with customized immobilization devices to hold you in the same position for each session; lie still and breathe normally during your treatment.
The linear accelerator will rotate around your body to deliver radiation beams from different directions. Your radiation therapists will be close by and will maintain video and audio surveillance of you during your treatment. If at any time you are in pain or are uncomfortable please speak up and they will assist you.
This form of prostate cancer radiation therapy is generally given five days a week, over the course of six to eight weeks.
Advantages of External Beam Radiation Therapy
Possible side effects of EBRT
Any numbers below used to describe the possible side effects relate to standard external radiation therapy, which is now used much less often than in the past. The risks of the newer treatment methods described above are likely to be lower.
Three-dimensional conformal radiation therapy (3D-CRT)
3D-CRT uses special computers to precisely map the location of your prostate. Radiation beams are then shaped and aimed at the prostate from several directions, which makes it less likely to damage normal tissues. You will most likely be fitted with a plastic mold resembling a body cast to keep you in the same position each day so that the radiation can be aimed more accurately. This method seems to be at least as effective as standard radiation therapy with lower side effects.
Intensity Modulated Radiation Therapy (IMRT) for Prostate Cancer
Intensity modulated radiation therapy (IMRT) is a state-of-the-art radiation delivery system.
IMRT uses beams that change shape during the treatment, creating multiple beamlets (beam segments) to vary the radiation intensity across each beam. This allows us to precisely conform the dose to match the exact 3D geometrical shape of the tumor, including concave and convex shapes, while sparing nearby normal tissue. IMRT treats difficult-to-reach tumors in the prostate with greater precision than conventional radiation. As a result, we are able to use higher radiation doses and minimize damage to the surrounding healthy tissue. Tumors that could be treated using conventional techniques can now be treated using much higher doses, resulting in improved cure rates, while reducing side effects.
Because of its greater degree of accuracy, IMRT may be a treatment option if you have reached the maximum allowable dose of prostate cancer radiation therapy and have a recurrent tumor in the treated area.
High-Dose Rate Brachytherapy (HDR)
High-dose rate (HDR) brachytherapy is an innovative form of internal radiation therapy for the treatment of prostate cancer.
Because the prostate gland is located close to the bladder and rectum, it is important for radiation treatment to be tightly focused on the prostate to avoid serious side effects. HDR brachytherapy offers a fast, precise way to administer prostate cancer radiation therapy for select patients. The radiation is deposited inside a tumor, delivering a maximum dose while minimizing exposure to the surrounding healthy tissue.
High-dose rate brachytherapy uses laser-thin, hollow catheters to deliver a precise, three-dimensional dose of radiation. The catheters are temporarily inserted in and around the prostate using image-guidance before each treatment.
The position of the catheters is checked with millimeter precision then a series of radioactive pellets are inserted into each catheter. Computer guidance controls how far the pellet goes into the catheter and how long the pellet stays in the catheter. This allows us to precisely target the location of tumors and release the radiation dose.
HDR Brachytherapy can provide a very precise treatment for prostate cancer that takes only a few minutes. Usually three treatments, taking 15 - 20 minutes, are given taking place over two days as opposed to several weeks for external beam radiation therapy. Radiation exposure to healthy tissues is minimized or eliminated altogether reducing side effects such as incontinence and erectile dysfunction. Because there is no incision and no surgical wound to heal, recovery from the procedure is generally rapid.
After the last treatment the catheters are removed. For about a week after treatment, you may have some pain or swelling in the area between your scrotum and rectum, and your urine may be reddish-brown.
These treatments are usually combined with external beam radiation given at a lower dose than if used by itself. The total dose of radiation is computed so that it is high enough to kill all the cancer cells. The advantage of this approach is that most of the radiation is concentrated in the prostate gland itself, sparing the urethra and the tissues around the prostate such as the nerves, bladder, and rectum.
Possible Risks and Side Effects of Brachytherapy
There is also a small risk that some of the seeds may move (migrate). You may be asked to strain your urine for the first week or so to catch any seeds that might come out. Be sure to carefully follow any instructions your doctor gives you. There have also been reports of the seeds moving through the bloodstream to other parts of the body, such as the lungs. As far as doctors can tell, this doesn't seem to cause any ill effects and happens very rarely.
Like external beam radiation, brachytherapy can also cause bowel problems, urinary problems, and problems with erections.
Conformal Proton Beam Radiation Therapy
Proton beam therapy is related to 3D-CRT and uses a similar approach. But instead of using x-rays, this technique focuses proton beams on the cancer. Protons are positive parts of atoms. Unlike x-rays, which release energy both before and after they hit their target, protons cause little damage to tissues they pass through and then release their energy after traveling a certain distance. This means that proton beam radiation may be able to deliver more radiation to the prostate and do less damage to nearby normal tissues. There is no long term data on proton therapy, although early results are promising, studies are needed to see if proton beam therapy is better in the long-run than other types of external beam radiation. Right now, proton beam therapy is not widely available. The machines needed to make protons are expensive, and there are only a handful of them in use in the United States. Proton beam radiation may not be covered by all insurance companies at this time.
The Foshay Cancer Center Experience
At the Foshay Cancer Center we have extensive experience treating prostate cancer. We were one of the first hospitals to perform temporary high dose rate implants. We are proud to stay at the forefront of leading edge technology in using image guidance technology, intensity modulated radiation therapy and the Varian Trilogy Rapidarc delivery system for prostate cancers.
Our facility is accredited by the American College of Radiology, as a patient this provides you with the assurance that we meet the highest standards of patient safety and quality care. Our fellowship trained, board-certified, Radiation Oncologists offer you their expertise combined with compassionate care.
For more information about prostate cancer treatment, call (561) 263-4400.