Mitch Oh, MD answers frequently asked questions about treating prostate cancer with radiation therapy. Dr. Oh is a radiation oncologist at the Tate Cancer Center and chair of radiation oncology at UM BWMC and clinical assistant professor of radiation oncology at the University of Maryland School of Medicine.
What is prostate cancer?
Prostate cancer is an illness that involves the male organ known as the prostate gland, which is in the pelvis. It's a small, walnut-sized organ that sits below the bladder. The nature of cancer is that it represents an abnormal growth of cells. This growth forms a mass which can cause local destruction. It can also spread to other areas of the body and cause damage to other parts of the body.
How is prostate cancer treated?
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.
What are the risks of radiation?
One of the important aspects of treating prostate cancer, and many other cancers as well, 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 minute to minute. Traditionally, our radiation treatment was designed to treat eat 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.
What is 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 to have the procedure done. 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. They are given a few days to recover before beginning the radiation process.
The radiation treatments themselves 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 over. We are also expecting that the treatment, because it is more accurate, will result in better results.
How can I reduce my risk of getting prostate cancer?
As men get older and get into an age group where prostate cancer typically occurs, we narrow that about half the men diagnosed with prostate cancer are older than approximately age 70, there are some suggestions we can make to help them minimize the risk or increase the likelihood of detection. The general recommendation is that screening for prostate cancer, including a PSA and a digital rectum exam should begin in the general public at approximately age 50. There are some recommendations that men who have a family history and African American men who have higher risk should begin their screening process earlier, with some organizations recommending screening in those men beginning at 45 or even 40.
The decision to initiate and when to initiate prostate screening is somewhat complex. There are certain pros and cons to doing the screening at all. We also know that there are certain lifestyle adaptations that men can assume. We know that there is some correlation with a high fat, low-protein, low-vegetable diet. As we age, all men should try to adopt a healthier lifestyle, not only in terms of reducing the risk of prostate cancer, but for obvious other health reasons. Unlike many other cancers, the association between smoking and prostate cancer has not been clearly defined. Though, generally, we advise all patients to stop smoking.