richard bevan-thomas md: let's take a momentto talk about radiation therapy for prostate cancer. how does radiation work? well, wetalked about surgery which is the removal of the prostate and radiation destroys theprostate, how does it destroy it. it sends specific type of radiation directly into thecells and what it does it, it destroys those cells and by destroying those cells, theythen turn into scar tissue. by turning into
radiation therapy for prostate cancer, scar tissue, the prostate then shrinks a littlebit and in addition, it can't grow any longer and there are different ways in which youcan deliver radiation to that prostate, let's talk about those. first of all, what we usedto call external beam radiation therapy, we now call intensity modulated radiation therapywhich is again the new goal standard for how
we treat prostate cancer with radiation. intensitymodulated radiation therapy does require a more advanced radiation center but it hasseveral advantages. the advantages that we have is that you can modulate how much radiationyou can do to the specific areas. old was called external beam radiation therapy andthe problem with that is we would have challenges with men with radiation affecting the rectumas well as radiation affecting the bladder. we tend to see that significantly less withthe newer technology. imrt sends photons directly in the prostate into those cells to causescar tissue. in addition, it is a longer treatment for that. now, long treatment means that youcan't give all the radiation in one dose and the reason why is because your body can'thandle it. so, everyday five days a week routinely
for a number of weeks, routinely it is aboutseven or eight weeks for about 10 to 15 minutes a day. radiation is sent directly in the prostate,it is a little bit like going on a 15-round, you know, boxing match. you can't go in forone round, you are going in for 15 rounds. so, if you can't knock the guy on the firstround, you got 14 more rounds to go and that is the way radiation works, at least imrtand external, the radiation actually goes from the outside. okay, very good, okay andanother way in which we can actually do that is what is called proton beam. now, protonbeam therapy is actually sending protons directly into the prostate. they have, what will theydescribe as pinpoint accuracy directly in the prostate, but there are some challengeswith both proton as well as photons, let's
talk a little bit about that. the proton beamtherapy is significantly more expensive than the photon therapy which is called imrt. itwas originally developed for kids and actually superficial spinal cord tumors, so that youdidn't damage the skin and as a result, you have fewer side effects to the surroundingstructures. well, a lot of proton beam therapy was then adapted to start treating other typesof cancers such as prostate cancer. more recently, the data has not shown any significant benefitfrom proton beam over imrt. it is significantly more expensive and as a result, it can actuallytake a little bit more time. the last way in which we can deliver radiation directlyto the prostate is what is called brachytherapy. brachytherapy is delivering radioactive seedsand they are implanted directly in the prostate.
as a result, those radioactive seeds, theywill give off radiation over a certain period of time and then they stop giving off radiation.now, you can either do that as an outpatient procedure which is a bit of majority of whatwe do, you can also have what is called high dose radiation therapy where they deliverthat radiation and you have to stay in the hospital for at least a day or several days,but the bottom line is that we are seeing less and less brachytherapy these days becausewhat has happened is that the other technology has gotten significantly better. whether youare looking at imrt, intensity modulated radiation therapy which is what we offer here at usmdcancer center or whether it is proton beam therapy, the side effects have become significantlyless but there are associated side effects
with brachytherapy which have the potentialof offering or having a challenge with urinary urgency and irritation which we see more oftenthan we do with the external therapy i.e. the imrt as well as the proton therapy. thebottom line is that there are risks for everything that we do for treatment of prostate cancerand the risk associated with radiation therapy is that it can affect the surrounding structures,it can affect the rectum which sits directly underneath the prostate, it can affect thenerves which are responsible for the erections and we have to be very careful with that becauseif these areas are affected and if they turn into scar tissue, we can subsequently affecta man's ability to have erections in the future and subsequently if you affect the rectum,some men develop the persistent urge to have
recurrent bowel movements as well as actuallyhaving blood in the stool as well as if it affects the bladder, you can also have bloodin the urine. these are some of the risk factors that are associated with delivering any typeof radiation to the prostate. some prostate cancers are high risk, aggressive,and more likely to spread. others are low risk, least likely to have bad outcomes. thebiopsy says cancer, but current diagnostic tools provide limited information about howaggressive a man's individual disease is, so most men decide to treat prostate cancerimmediately. once treated, many men experience serious long-term side effects like incontinenceand sexual impotence. immediate treatment is not always needed, but right now a mancan't be sure if his cancer is the kind that
is likely to require treatment or if he isokay to wait for now. what if there was a test that could determine how aggressive prostatecancer is. genomic health is developing a new test to do just that. by reviewing theunderlying biology of the tumor and using genes from multiple biologic pathways, thetest can predict the aggressiveness of prostate cancer when diagnosed, allowing a man to makea more informed treatment decision with confidence, taking care of himself with more informationand greater peace of mind.
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