Last Modified: June 1, 2008
Dear OncoLink "Ask The Experts,"
I had a prostatectomy and now have a recurrence. My doctor plans to treat with radiation therapy. I have read about the Calypso system, is this an option for me?
Neha Vapiwala , MD, Senior Editor of OncoLink and Chief Resident in the Department of Radiation Oncology at the Hospital of the University of Pennsylvania, responds:
Known as GPS for the Body, the Calypso® System is comprised of three tiny transponders, each the size of a grain of rice, that are implanted into a patient's prostate prior to starting radiation therapy. They are used to precisely track the prostate, detecting even the slightest organ movement. This is important because normal physiologic events such as eating, breathing, and coughing can all cause movement of internal body organs. This is particularly important for prostate cancer patients, as the prostate gland has been noted to move significantly and variably from patient-to-patient and from second-to-second. Consistently tracking the movement of the prostate gland allows the radiation oncology team to adjust the radiation beam if the target moves out-of-range, and even to stop treatment if necessary in order to readjust the patient's body. This enables the delivery of highly accurate radiation therapy, while avoiding radiation delivery (and unwanted damage) to the surrounding normal tissues and organs.
The system can be used in men with an intact prostate who will be receiving radiation therapy. The U.S. FDA recently approved the system to also be used in the post-prostatectomy setting. Patients with certain high-risk post-operative features such as high Gleason scores, extracapsular extension, positive surgical margins, or seminal vesicle involvement are at risk of developing biochemical failure following radical prostatectomy, and thus can be treated with adjuvant (after surgery) radiation with Calypso to help reduce this recurrence risk. In addition, the system can be used to treat patients with salvage radiation, meaning patients who are post-prostatectomy and develop known biochemical failure and/or a local recurrence, but do not have distant disease.