June 22, 2011
GPS Technology Used To Treat Prostate Cancer At St. Anthony Hospital
Radiation oncologists at the Jane Thompson Russell Cancer Care Center at St. Anthony Hospital in Gig Harbor now use GPS-like technology to provide prostate cancer patients the breakthrough benefits of real-time tumor tracking during radiation therapy.
The technology, called GPS for the Body®, allows higher doses of beam radiation to be directed at the tumor with increased accuracy while decreasing risks for exposing healthy tissue and organs to radiation.
"We are committed to providing our patients with state-of-the-art treatments that maintain or improve quality of life," said Radiation Oncologist Kenneth Bergman, MD.
The Jane Thompson Russell Cancer Care Center added the innovative prostate cancer therapy in May 2011. The outpatient cancer center is a partnership between the Franciscan Health System, St. Anthony Hospital, Peninsula Radiation Oncology and Northwest Medical Specialties.
Prostate cancer is among the many types of cancer treated at the center. Prostate cancer is second only to lung cancer as the leading cause of cancer-related deaths in men, according to the American Cancer Society. The prostate is a walnut-sized gland located below the bladder.
The goal of external beam radiation therapy is to focus the radiation beam on the tumor while avoiding the irradiation of surrounding healthy tissue that can result in serious side effects like sexual dysfunction. However, internal organ movement, which naturally occurs as part of normal body functions such as digestion and breathing, may cause radiation beams to miss the intended target.
"Like many of the organs in our body, the prostate gland is constantly moving," said Dr. Bergman. "With precision targeting, extremely accurate radiation can be delivered directly to the tumor while minimizing the risk of any harmful effects on normal tissues. By doing so, we are likely to reduce side effects."
Key features of the Calypso Medical system are three electromagnetic transponders, each the size of a grain of rice, implanted in the prostate before radiation therapy begins. These serve as beacons that continuously monitor the tumor’s location during radiation therapy.
Dr. Bergman and his team can see immediately whether the radiation beam is off track and then make adjustments, or reposition the patient, as needed to ensure delivery of radiation with pinpoint accuracy. "Prostate motion is unpredictable and variable, based on breathing and filling of the bladder and bowels," Dr. Bergman explained. "During treatment, it may shift several millimeters as the patient breathes or coughs."
A clinical study published May 2010 in the medical journal, Urology, concluded that GPS technology reduces urinary, bowel and sexual dysfunction side effects that are common with prostate cancer radiation therapy. The technology is similar to the global positioning system technology used in many vehicles and cell phones.
Historically, radiation oncologists have used several methods to localize a tumor and limit organ motion during radiation therapy, such as keeping the patient immobile. Older localization methods – which used implanted gold markers and X-ray images or ultrasound scans – image the tumor before each radiation session. None has the precision or immediacy of the GPS for the Body technology now used at the Jane Thompson Russell Cancer Care Center.