Prostate Cancer Treatment
The treatment of prostate cancer is varied and fairly complex. The options vary from what we call watchful waiting, which involves close surveillance or observation of the patient, surgical removal of the prostate, external radiation and seed implantation. A final option is hormone therapy in some men. These treatments can be given as an isolated treatment or in combination. The decision to select one treatment over another is very complicated and should involve discussion with a patient's physicians.
One of the important aspects of treating prostate cancer, as well as many other cancers, is this new concept of organ motion. Typically, and historically the way prostate cancer was treated with external radiation is that the gentleman would lie on his back, and there would be a mold made to position him in a reliable and reproducible fashion. Marks would be put on his skin to help with the alignment process. What we've learned over the past several years is that despite the effort to keep the external anatomy of the patient still and reproducible, internal organs actually move. They move because of respiration, because certain organs fill and empty, such as the bladder and the bowel. As a consequence of that, we've learned that the prostate can move quite a bit, not only day to day, but also minute to minute. Traditionally, our radiation treatment was designed to treat the prostate assuming it had a static position.
The issue with organ motion, or the prostate moving during radiation, is that it can actually move away from the treatment field so that the radiation actually misses the prostate. The other issue is that we will sometimes make our treatment field larger to compensate for the movement, and that inherently requires greater treatment of surrounding tissues. If we were able to develop a way to account for the motion, we could ensure greater reliability in hitting the target or the prostrate with the radiation, and minimize the amount of radiation hitting the surrounding tissues.
GPS for the Body
GPS for the Body is a new system devised by a company known as Calypso. It is a system that falls right in line with our attempt to track the prostate during radiation treatment. It involves small little devices called beacons which are approximately the size of a grain of rice. These beacons--three, specifically-- are placed into the prostate. They emit an electromagnetic wave that is picked up by the radiation machine, the linear accelerator. The linear accelerator is able to track the prostate during the treatment to account for organ or prostate motion.
How does GPS for the Body work?
The process of placing the beacons is relatively simple and straightforward. It's done in the same-day surgery suite, typically under light anesthesia. The beacons, which are the size of a grain of rice, are placed into the prostate through the rectum. The process is very well tolerated. Studies have shown that the complication rate is very low.
One of the advantages of the beacons is that the vast majority of men are candidates for the procedure. There are very few counter indications. The placement of the beacons generally takes only a few hours. The patient is generally sent home on the same day and is given a few days to recover before beginning the radiation process.
Radiation treatments can generally take 7-8 weeks, Monday through Friday, five days a week. The advantage of the beacons is that less normal tissue around the prostate can be treated, and we expect that this will translate to better tolerance during the treatment, and a lowered risk of side effects once the treatment is complete. We also expect that the treatment, because it is more accurate, will result in better results.