Advances in Prostate Cancer Treatments
By Greg Maggass, MD, Arizona Radiation Oncology Specialists, Scottsdale LIVING WELL Magazine
Stereotactic body radiotherapy (SBRT) of the prostate is a new form of external beam radiotherapy capable of accurately and precisely delivering a concentrated dose of radiation to the prostate. This procedure is also known as prostate radiosurgery. This technique involves not only delivering high daily doses of radiation utilizing unique beam arrangements, but stable patient positioning and an ability to target the prostate gland and guide the beam during treatment to account for prostate motion. This allows us to deliver a very homogeneous, concentrated dose of radiation to the prostate gland, while sparing the surrounding normal tissues.
At Arizona Radiation Oncology Specialists we are the first and only radiotherapy center in the U.S. to pair the TrueBeam tm Linear Accelerator manufactured by Varian to the Calypso targeting and tracking system, which is also known as GPS for the prostate. Our TrueBeam tm Linear Accelerator is equipped with a high-definition multi-leaf collimator, which is a device that allows for precise and fine sculpting of the cloud of radiation to conform exactly to the prostate gland. The Calypso system, which works by placing three GPS Beacons into the prostate, allows us to precisely target the beams to the prostate at the beginning of treatment, as well as monitor prostate movement and account for it during treatment with millimeter accuracy. We are able to monitor for prostate motion on a real time basis, and account for movement as it occurs.
Other systems, which are commercially available, will use ionizing radiation (x-rays) to track the prostate motion. Unfortunately, these x-ray based systems not only expose the patient to additional radiation, but are only able to monitor the prostate’s position every 30-40 seconds, as the images need to be electronically processed and evaluated. By combining the radiosurgical techniques available with the TrueBeam tm Linear Accelerator and the Calypso targeting and tracking capabilities, we are able to deliver a high dose of radiation to the prostate to control the cancer while minimizing potential side effects.
The course of prostate radiosurgery involves a series of five treatments given every other day.
Treatments are delivered as an outpatient and patients are able to drive themselves and continue to lead a normal active lifestyle during the course of treatment. We are able to schedule the treatment sessions to minimize the impact on a patient’s daily routine. This also allows us to offer these treatments conveniently to people who do not live near our center, as it only requires a brief stay.
Not all patients are candidates for stereotactic radiosurgery as a definite treatment. Patients suitable for these treatments have early stage (Tl or T2) adenocarcinoma of the prostate without evidence of regional or distant spread. Gleason score should be less than or equal to seven, with a PSA less than 15. Patients who have undergone prior hormonal therapy are still eligible to undergo stereotactic radiosurgery as a definitive treatment.
Gregory Maggass M.D. is a board certified in radiation oncology by the American Board of Radiology and a Fellow of the American College of Radiation Oncology. He has also been named as a “Top Doc” in Phoenix Magazine and received the national “Best Doctors” ranking. Arizona Radiation Oncology Specialists has offices in Scottsdale, North Phoenix, and Gilbert.
Phone: 480-619-6196 or on the Internet at www.cancerAZ.com.
