Personal Perspectives on Current Prostate Cancer Topics

Mark A. Moyad, MPH

So, it is time to bring you up to date on some of the latest news. Some of it is good, some bad, and some indifferent (just like life). Keep in mind that some studies looked at preventing prostate cancer and some studies looked at changing the course of this disease after men were diagnosed with prostate cancer. Regardless, whatever looks good for prevention may be effective for men after a diagnosis and vice versa so you should keep this in mind. Lets get started because there is a lot to talk about in the world of complementary and preventive medicine.

1) ZINC SUPPLEMENTS IN EXCESS MAY BE BAD FOR ME?
In a disturbing way, this latest study gives me a sense of vindication. In 2000, when I wrote the book the ABCs of Nutrition and Supplements I mentioned that I do not recommend zinc supplements in high dosages. Well, I received some hate mail because many men did not understand why I would not recommend a supplement that so many alternative medicine books seem to advocate for prostate problems. The reason I could not recommend these supplements in high dosages was because there was no strong data to support the use of these supplements. In fact, several dietary supplement and dietary studies of men who took zinc found that it may increase the risk of prostate enlargement and could cause immune suppression. Regardless, the bottom line is that we did not have any large studies on zinc supplements and prostate cancer until now.

A recent investigation from the Health Professionals Follow-Up Study of 46,974 U.S. men followed for 14 years found something very interesting (Leitzmann MF, et al. Journal of the National Cancer Institute 95:1004-1007, 2003). A total of 2901 cases of prostate cancer were diagnosed during this study. Compared with men that did not use zinc supplements, men who consumed more than 100 mg/day of zinc supplements had over 2 times the risk of being diagnosed with advanced prostate cancer. In addition, men who took individual zinc supplements for 10 or more years also had a risk of advanced cancer that was over 2 times more than those who did not. What does this mean to you??? Well, until we get more data men should NOT take individual zinc supplements, especially those that contain 100 or more milligrams per day of zinc itself. I am not worried about the amount of zinc in a multivitamin (like One-A-Day or Centrum), but I am worried about high-dose zinc supplements. Zinc is absorbed in the prostate and may even help with the uptake of testosterone. Regardless, this first large study is very concerning. So, it is better to be safe than sorry right now. The bottom line is that most of you should stay away from large dosages of zinc supplements until we get more data!!!

Currently, some eye doctors are recommending zinc supplements for macular degeneration (a specific eye disease that could lead to blindness). In some cases the benefit of zinc for this situation may outweigh the risk of prostate cancer and vice versa. The amount of zinc that was used in the macular degeneration research was 80 mg a day for those with intermediate to advanced stages of this disease. So, talk to your eye doctor about this latest research to decide if zinc is right for you. Otherwise, for most other individuals, high-dose zinc supplements should be avoided until we get more data.

2) Why is it important that I maintain a normal weight after being diagnosed with prostate cancer???
If I live to be 100 years old (a big if), I am not sure that we will see a larger study than the one that was published recently (Calle EE, et al. The New England Journal of Medicine 348:1625-1638, 2003). A study of over 900,000 U.S. adults (404,576 men and 495,477 women) who were free of cancer in 1982 were followed for a total of 16 years. Men who were obese had a 20% increase in the risk of dying of prostate cancer and men that were severely obese had a 34% increase of dying from prostate cancer. This study was very concerning because not only is obesity a risk factor for many diseases, it seems that preliminary research suggests that obesity somehow places a men at a higher risk of dying from prostate cancer. Lets face the facts, weight and weight gain is not a fun subject to talk about, but the fact is that maintaining a healthy weight may be one of the best things you can personally do to reduce your risk of dying early from a number of diseases.

3) Can an aspirin a day keep the prostate cancer away???
I have talked for years about the potential benefits of taking aspirin. It seems that many men and women that could qualify for aspirin therapy are not taking it, and many individuals that do not qualify for aspirin are taking it. Regardless, in the Health Professionals Follow-up Study of 47,882 U.S. men (mentioned earlier in this article), researchers found a potential reduction in the risk of metastatic prostate cancer in those men that took aspirin almost daily (Leitzmann MF, et al. Cancer Epidemiology, Biomarkers & Prevention 11:1108-1111, 2002). It seems that baby aspirin or regular aspirin may be beneficial but first talk to your doctor to see if you qualify for aspirin or ask your doctor to go the website www.med-decisions.com to see if you may qualify for aspirin therapy. Aspirin can increase the risk of internal bleeding and ulcers so you want to be 100% sure to see if you qualify for aspirin therapy. Regardless, it is possible to reduce the risk of a first or second heart attack by taking aspirin, and aspirin may reduce the risk of colon cancer so it is not surprising that aspirin may have an effect on prostate cancer. Again, do not start taking aspirin until your doctor gives you the green light!

4) Can lowering your cholesterol have an impact on prostate cancer???
A recent study from the Netherlands of approximately 300,000 individuals found that those individuals taking cholesterol-lowering drugs may reduce their risk of prostate cancer (Beiderbeck AB, et al. American Society of Clinical Oncology 22:846 abstract #3400, 2003). Again, as with aspirin therapy I have mentioned for years that keeping your cholesterol low may not only reduce the risk of a heart attack, but may also have an impact on prostate cancer. Of course, this is only a preliminary study, but what the heck! We have to look at the big picture here. Check with your doctor ASAP to see what your cholesterol level is at this time. You may qualify for a cholesterol-lowering drug or you may be asked to change your diet to reduce your cholesterol level. Anyhow, keep in mind that what is heart healthy is also generally considered to be prostate healthy!!! Apart and in addition to diet, there are some many ways to reduce a high cholesterol level that you and your doctor should discuss them.

5) Are garlic and other similar compounds good for your prostate???
Again, keep in mind that what is heart healthy is generally found to be prostate healthy. Therefore, it should not be a surprise that a recent study from China found that those men that consumed Allium vegetables (garlic, scallions, onions, leeks, and chives) were found to have a lower risk of prostate cancer compared to men that did not consume these types of vegetables (Hsing AW, et al. Journal of the National Cancer Institute 94:1648-1651, 2002). Regardless, garlic and other similar vegetables seem to be heart healthy so I would encourage men to eat these things. Now, I am not talking about garlic supplements but dietary garlic. Of course be careful with garlic because when consuming this vegetable it could create a lot of problems in the romance category so make sure you stick to moderation.

6) Does finasteride (Proscar®) reduce the risk of prostate cancer?
You may have read recently about the potential good news and bad news scenario of taking 5 mg of finasteride (Thompson IM, et al. New England Journal of Medicine 349:213-222, 2003). Basically, over 18,000 men 55 years of age or older with a normal DRE and a PSA level of 3 or lower were either given 5 mg of finasteride daily or placebo for 7 years. Men taking finasteride reduced their risk of prostate cancer by approximately 25%!!! Wow!!! However, there was a higher risk of being diagnosed with more aggressive prostate cancer (Gleason 7-10) in the finasteride group versus the placebo ("sugar pill") group. A better way of looking at the confusing results of this study is that if 1000 63 year old men are followed yearly for 7 years there will be about 60 prostate cancers diagnosed and about 18 of these 60 cancers will be aggressive. However, if these same men were to take finasteride for 7 years there would only be about 45 cancers diagnosed, but 22 of these cancers would be more aggressive. Why did this happen??? It is possible that 1) finasteride does not actually increase the risk of aggressive prostate cancer but it gives the appearance of more aggressive disease. In other words, it is possible that this was just a pathology error. In other words, finasteride may give the appearance of a more aggressive prostate cancer because it shrinks the prostate. 2) It is possible that by reducing the levels of more potent testosterone (DHT) that cells in the prostate become more aggressive because they develop more androgen independence. 3) It is possible that finasteride reduces the prostate gland enough so that it is easier to detect a more aggressive cancer on biopsy. Blah, blah, blah,… what does this all mean to you???

Talk to your doctor about the latest results of this study. The researchers in this study are performing more tests to see whether or not finasteride actually increases the risk of aggressive prostate cancer. Currently, we do not have an answer to this question. Ultimately, as the men in this study are followed we will have a better answer. In the meantime, it is important to keep in mind that a total of 5 men in the finasteride group and 5 men in the placebo group died in this study from prostate cancer. Approximately 99% of the men in this study died from other causes including cardiovascular disease. Therefore, and in my opinion, knowing your cholesterol level as well as your PSA is obviously very important. Personally, I think that this study was brilliant and the researchers and patients in this study should be given a lot of credit. I am excited that finasteride may have an effect not only on prevention but could favorably impact prostate cancer, but I am waiting for more results. In the meantime, another drug called "dutasteride" is being tested (ask your doctor to keep you up to date on the latest results of finasteride and dutasteride to see what role these drugs have on prostate cancer).

There is so much more to discuss when it comes to the latest research on prostate cancer and we will cover this in the next issue of PAACT. I apologize, but I need to get some rest and get the next article ready for the next issue. In the meantime, I do sleep with a clear conscience because the book that we put out several years ago seems to be supported more than ever by the latest research. If you want to still order the book call 1-800-462-6420 (National Book Network) and ask for the ABCs of Nutrition and Supplements for Prostate Cancer by Mark Moyad. This is a shameless promotion but I am proud to say that most of the predictions in this book seem to be supported by the latest research! Now, if you do not want to spend the money you could always photocopy portions from the library or your doctor's office or you could print out some of the articles from the internet. Regardless, I wish all of you the best of health and a wonderful summer and fall and look for more recent research in the next issue of PAACT.