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Medical Forum / Diseases and Disorders / Prostate Cancer / December 2004interesting comments from a prostate cancer lecture.....
dr. alan r kristal gave a lecture on prostate cancer and prevention which was video taped. it was on a college classroom channel. i was taking notes on it and then went back to double check them to make sure i wasn't going to say something that wasn't true that he said. he does a lot of research on foods and prostate cancer prevention at the fred hutchinson cancer research center. i found some of the things he say to be known facts but other items he brought up have never been mention. it is the latter items that i'm going to post here. on food and prevention. there are two groups - lycopene and crucifecious vegetables. there is a weak relationship between prostate cancer prevention and tomatoes. lycopene in the raw form such as eating tomatoes only reduces the chance by 16% and eating tomato paste does increase that number to 23%. but curcifecious vegetables definitely showed a greater correlation between the food and prostate cancer prevention. it can reduce your chances by as much as 40%. there was some differences in the different curcifecious vegetables. the basic action these vegetables is protect the DNA from breaking down. he did explain why the cooked food is not as good for the body in getting the needed nutriment into the body. there is an enzyme that is released that causes the plant's cell structure to break down releasing the nutriment. when the food is cooked, it destroys the enzyme and the nutriment stays in the food except for the little bit of processing our body can do to it. he said that it's about 7 times stronger than if it is cooked. he did say that calcium intake should be kept down to about 2 glasses of milk a day. now, here is where he drifted off the path from what we discuss at the newsgroup. he said that psa testing is not effective and gave the usual examples to support it. i wasn't impressed. he also said that DRE's were not effective as detection for prostate cancer either. he used an example that if 25% of the men are known to have prostate cancer at a certain age, one would be better off to assign random numbers to the men because you would stand a better chance of finding the prostate cancer than using the DRE for that. you can draw your own conclusions from that example. maybe leonard can shed some light on this. what i found interesting is that he made the comment that at age 50, that 15 to 20% of the men have biopsy proven prostate cancer. but the cancer is benign and doesn't grow. he said at this point, you are on a slippery slope. that is when he said the psa comes into play. because when he takes off, then the psa will show the sharp rise and one knows the cancer has become active. he did go into the gleason score some and explained that the cancer cells grow around the duct of the prostate cell. the more cells that grow around the duct, the more aggressive the cancer is. also, the cancer ruptures the prostate cell membrane and causes the release of more psa into the blood stream which is how one gets the increase in the psa number. he made the comment that a high fat diet is one of the main causes in RP failures after surgery. of course, the dr. is dealing in food research. those of the facts he put out. whether they can argued one way or the other is up to personal opinion. ~ curtis knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc Curtis, Excellent summary. Nice to see some sort of numbers on the food angle. Thanks! jimhoney > dr. alan r kristal gave a lecture on prostate cancer and prevention > which was video taped. it was on a college classroom channel. i was [quoted text clipped - 41 lines] > because you would stand a better chance of finding the prostate cancer > than using the DRE for that. This is a simple calculation, but it to do it, I would have to know what he thinks the probability of detecting cancer with a DRE is. But his assumption of 25 percent likelihood for prostate cancer seems off. It is known that, in the US, about 16 percent of men will be diagnosed with prostate cancer some time in life. I would have to think about what this means about what would happen if you selected men at random over 50 and biopsied them. But 16 percent seems like a reasonable estimate. Also, if you selected men at random and biopsied them, you would detect a mix of innocuous cancers and cancers which were growing. No one knows just what that mix is. One studied showed that for men over 55, with PSA below 3 and normal DRE, about 15 percent showed cancer on biopsy. More important, the calculation would only be valid if DRE were the sole method used to test for prostate cancer. As we well know, that is not the case. PSA testing, combined with DRE, is the method used, with the great bulk of biopsies being ordered because of suspicious PSA results. In the days when DRE was the only method used, we know that it was something of a crap shoot as to whether or not a prostate cancer would be caught before it had metastasized. That was the point of introducing PSA testing. It has still not been established by air-tight statistical methods that PSA testing is effective, but indirect evidence suggests it is. The number of deaths due to prostate cancer has dropped over 25 percent in the US in the era of PSA testing, depsite an increase in the vulnerable population. Also, urologist report that many fewer of their cases present with strong evidence that the cancer has already spread. On the other had, as the above figures indicate, a certain number of prostate cancers that are currently being treated will probably never bother the patient during his lifetime. Most urologists won't treat prostate cancer aggressively in older men with limited lifespans, but a few do. They almost all will treat younger men aggressively if the cancer appears curable, so the important question is how many such men are being needlessly treated. Skeptics like Krystal suggest that this is close to 100 percent of such men, but I don't think the evidence supports that or anything close to it. This is a complex problem, and we need more and better data, and fiddling with numbers as he does doesn not further our understanding. It is to be hoped that recent efforts to use modern molecular biology to discriminate aggressive from non-aggressive cancers will provide the key in the next several years. Unfortunately, we are not there yet, and those of us in this newsgroup have had to make do with what is now known, which includes significant uncertainties. It is very likely that some of us were treated by radiation or surgery who would never have been bothered by our cancers if left alone. But, at present, there is no way to tell which of us were in this category. A gambler might be willing to take the chance, but most of us are not interested in taking such chances. > you can draw your own conclusions from > that example. maybe leonard can shed some light on this. > > what i found interesting is that he made the comment that at age 50, > that 15 to 20% of the men have biopsy proven prostate cancer. but the > cancer is benign and doesn't grow. That must refer to the study I quoted. Note that this was just one study, and one always wants more than one study to confirm the data. But it is probably in the correct ball park. But note that among that 15 to 20 percent, as I noted above, SOME of those cancers are benign as they stand, and some are not. He has no idea how those break up, so assuming almost all of them are benign is unwarranted. > he said at this point, you are on a > slippery slope. that is when he said the psa comes into play. because > when he takes off, then the psa will show the sharp rise and one knows > the cancer has become active. That is true within limits. That is, when the PSA starts taking off, that is an indication that something may be going on. But note that a man could have a benign prostate cancer which will never bother him, and he may also have BHP or develop chronic prostatitis. More important, a certain number of men with aggressive prostate cancer never have any abnormal PSA readings. Presumably, that might show up in a biopsy in terms of tumor volume or Gleason grade. But, in current practice, where we don't randomly do biopsies, such men will not be diagnosed until a doctor feels something on DRE. So pragmatically we have to rely on following PSA values. > he did go into the gleason score some and explained that the cancer > cells grow around the duct of the prostate cell. the more cells that [quoted text clipped - 7 lines] > > of course, the dr. is dealing in food research. He has a doctorate in public health. He is what is called an epidemiologist. He is not an MD, but that doesn't mean he wouldn't be qualified to talk about some aspects of prostate cancer. His research does seem to be concerned with the relation between diet and cancer. So what he says about more general aspects of prostate cancer should be taken with a grain of salt. He doesn't necessarily know more about it than some of us here do. > those of the facts he put out. whether they can argued one way or the > other is up to personal opinion. [quoted text clipped - 5 lines] > invariably fatal. Prostate cancer is only sometimes so." > http://community.webtv.net/PALMER_ENT/doc > those of us in this newsgroup > have had to make do with what is now known, which includes significant [quoted text clipped - 3 lines] > were in this category. A gambler might be willing to take the chance, > but most of us are not interested in taking such chances. While I certainly wasn't going to gamble by avoiding RP in my case (T3cN0M0, Gleason 8), I tend to agree so far with two things Scholz said in PCRI Insights, which are becoming the central theme of my impending early HT decision, which I expect to present to my docs a week from now: A. The major difference between treatments today is likely to be quality of life, not length of life. B. The multiple different treatment choices offer indistinguishable survival rates but widely varying SEs. Thus SEs drive the treatment choice. Is it really a gamble if we balance the virtual certainty of significant HT SEs against a debatable 20% benefit of post-RP, zero-PSA, preemptive HT? and c palmer wrote: > > dr. alan r kristal gave a lecture on prostate cancer and prevention > > > > [pertaining to] food and prevention . . . there are two groups - lycopene and > > crucifecious vegetables. there is a weak relationship between prostate > > cancer prevention and tomatoes. [quoted text clipped - 4 lines] > > he did say that calcium intake should be kept down to about 2 glasses of > > milk a day. Tomatoes/lycopene work better cooked, a la catsup, tomato sauce, stewed, etc. Plus, the OTHER edge of the cacium sword is getting sufficient calcium to fight osteoporosis if testosterone is low for any reason. The most definitive statement I've seen on that so far said to make sure we get the updated USDA recommended amount of calcium -- about 1,500 mg -- especially if our T is low. That's equivalent to about five glasses of milk a day, if that were our only source. OTOH, I've seen summaries I trust that say no clinical proof yet exists that diet can influence the development or progression of PC. (But I quit eating sat fat 20 years ago anyway, for other obvious reasons.) Jeez . . . and we thought choosing a car or a house or a wife was a challenging decision! Maybe the complexity, the uncertainties, and the marginal benefits of adjuvant therapy w/low PSA really do relegate the decision to a simple QOL choice, taking much of the gamble out of the dilemma. I.P. Curtis: I watched the same program, but almost turned it off when he was introduced as a former chef. His slides were not the greatest, but he was an accomplished speaker who may have really done more harm than good. Paul leonard wrote.... He has a doctorate in public health. He is what is called an epidemiologist. He is not an MD, but that doesn't mean he wouldn't be qualified to talk about some aspects of prostate cancer. His research does seem to be concerned with the relation between diet and cancer. So what he says about more general aspects of prostate cancer should be taken with a grain of salt. He doesn't necessarily know more about it than some of us here do. ========== i definitely agree with you leonard. as i watched, i could tell that he was more knowledgable from the food aspect than the medical aspect. ~ curtis knowledge is power - growing old is mandatory - growing wise is optional "Many more men die with prostate cancer than of it. Growing old is invariably fatal. Prostate cancer is only sometimes so." http://community.webtv.net/PALMER_ENT/doc |
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