M. D. Anderson Cancer Center
Cancer Newsline Audio Podcast Series
Date: January 5, 2009
Duration: 0 / 12:04
Return to Cancer Newsline
Welcome to Cancer Newsline, a weekly podcast series from The University of Texas M. D. Anderson Cancer Center. Cancer Newsline helps you stay current with all the news on cancer research, diagnosis, treatment and prevention, providing the latest information on reducing your family’s cancer risk. I’m your host Lisa Garvin.
Today we’re talking with Wendy Demark-Wahnefried, Ph.D. a professor at M. D. Anderson's Department of Behavior Science. She led a study which found that taking flax seed before surgery may provide a protective effect for prostate cancer patients. First of all, welcome Dr. Wendy Demark-Wahnefried.
Thank you, it’s a pleasure to be here.
Let’s talk about your study a little bit. What was the basic premise of your study?
Well we found in some previous studies in mice and cell culture that flax seed has some very interesting compounds in it that may prevent cancer. So we designed a phase two trial that was funded by the National Cancer Institute and it was a multi site trial and in which 161 men throughout the country took part in a study where there were randomize to receive flax seed before they got there prostate cancer surgery or a low fat diet or flax seed plus a low fat diet or just their regular diet and they follow the diet for the time they had pre-surgery usually around 34 days and then when their prostates came out we examine them under the microscope and saw how fast the cancer cells were dividing.
Now explain…apparently it shows that because there has been a lot of talk about diet and prostate cancer and different supplements. So it seems like it wasn’t the diet that was really making the difference it was the flax seed… yes?
Yes, well in our previous studies we had done some pilot studies in men we always combine the flax seed supplement which was three rounds table spoons of flax seed a day. We combine that with a low fat diet because we thought that the flax seed would work better. There’s a host of biological pathways that would kind of argue for that point. However for this trial when we went to see…and let me digress a little bit but so in those pilot studies we found that when we had the men follow the low fat flax seed supplemental diet that their PSA’s their prostate specific levels dropped and they got off there response in there surgical specimen and so when we went for this trial we need to separate out the two was it the low fat diet or was it the flax seed that was more responsible for this biological effect and so in this phase two trial we found out indeed that it was the flax seed and not the low fat diet.
Now what was the exact action that the flax seed was it shrinking the tumor was it making the PSA levels lower? How exactly was it working?
What we saw in the tumor was that the cells the men who took the flax seed their tumor cells where not growing as quickly as the men who didn’t take the flax seed. So that was the primary effect as it turns out we did not see any difference in PSA levels between the various groups in the study. So that was a little bit of a surprise for us and the one thing to keep in mind is that the PSA sometimes can be a fickle what they call a fickle biomarker in that its affect can be modified by a host of different factors. Infection, prostate manipulation all kinds of different things um... and so we may not have seen the affect on PSA but we say the biological affect which is really exciting.
We covered it just a little bit earlier but what were your findings?
Ok, so the findings were that the men who took the flax seed that where randomized to the flax seed supplemental diet or to the flax seed diet plus the low fat and we but not the low fat alone or not the control group. Those two flax seed supplemental groups had a much lower rate of cell growth or cell proliferation in their tumors.
That’s pretty amazing I mean what lead you to look at flax seed in the first place?
Um…well we originally we weren’t looking at flax seed we were actually looking to investigate fish oil and fish oil is very high in omega 3 fatty acids. But we had some problems with the fish oil men were burping it up and saying that they tasted fish. It also had some GI side affects at the doses we were using. So we switched to flax seed because flax seed also has omega 3 fatty acids and it also has a fiber in it a fiber related component rather that’s called lignan. Lignan may be very important for regulating hormonal levels so therefore we started to explore and got some favorable affects then we followed up further and then ultimately culminated into this trial.
Do you feel that this is form the basis for future study. I mean can you go off in many different directions now or maybe own your research now that you done this?
Yeah, that’s a really good question absolutely we would like to be able to see before we can really start saying that flax seed has a protective affect for men with prostate cancer. We really need to test it in other prostate cancer populations and other cancer populations for that matter. And then therefore were kind of thinking of another trial that we can then perhaps propose to the NIH that would test flax seed maybe in men who are being treated with radiation and see if it has similar sorts of affect. Right now that trial is still in our heads and not on paper and we need to do some further thinking about it.
Was the control group healthy men? Or were they prostate cancer patients?
All the men who participated in this trial were men that had prostate cancer that were awaiting surgery to take out their prostates and their tumor.
Cause I want to make that clear to the audience, it's not like every man should run out and buy flax seed now, but perhaps prostate cancer patients might… is there a take home message for prostate cancer patients at this point? Or is it still to early?
Well at this point in time it’s a little to early we need to replicate our findings. Ultimately this will be a perfect trial for prevention because ultimately what we would like to do is to be able to prevent prostate cancer before it happens and something as innocuous simple to take as flax seed. It only cost pennies to take would really be advantageous. But again a little bit to early.
How many procedures would you say you do in a typical year here at M. D. Anderson?
It varies. I mean I think that we, over the last year or so, we have probably done more. But generally this is a procedure that perhaps we are doing, on average, we're doing about one every three months or so, and again we will have months where we will perform two in one month so it really varies as to which patients are candidates for that and the referral pattern. And those types of things - certainly it’s an option that we have available and favorably we see a lot more patients asking about the procedure now.
But it seem like prostate cancer, in other studies and other findings, there's been a lot of focus on diet and obesity and it's been linked to prostate cancer - that’s a pretty enough definite connection isn’t it?
Well as far as obesity and cancer, it doesn’t seem to have a link to men who just get the disease. It seems more linked to men who get aggressive disease and ultimately die of the disease. So regulating body weight is important for men with prostate cancer because it's been linked to men really dying of the disease.
This is interesting because we had a major trial, a select trial, that was looking at Selenium and Vitamin E for prevention of prostate cancer and apparently does not provide any protective or preventive effect, so do you feel like maybe men will say “Oh we've been through this before, this is just the herb of the week.” Do you think people might not take this seriously?
As a nutritionist one of the things I think that has acted to our detriment, is to actually take the nutrients out of the food and then test it. In the case of flax seed, flax seed is a complex food it has a lot of different nutrients in it therefore a lot of different nutrients that could help prevent cancer. When you take one nutrient and expect that it’s going to necessarily be the magic bullet it has characteristically or historically acted in the complete opposite direction. For example the ATBCB trails where they tested beta carotene and found that men who got the beta carotene actually had higher rates of cancer than those that didn’t. So in some ways the select trial is progress, if you will, at least it didn’t show that it's made the cancer worse or caused cancer. So I think knowing what we learn from supplements some of the supplement trials have actually showed that. In fact, they had a head and neck cancer trial that tested Vitamin E and in that trial the men that actually received the vitamin E died at a higher rate, was much worse. So we don’t really have good success when we try new single nutrient and that’s somewhat out lack of success in that area, could be that we just rush those trials, we don’t get the right form of nutrient before we go forward. Again, flax seed complex food, so it’s a different substance.
So where do you go from here?
Where we go from here... Well we will test, hopefully we will be able to get funding to test flax seed in different prostate cancer populations again men that receive radiation therapy perhaps. Perhaps men that after they have their prostate cancer surgery, their PSA start to climb or perhaps in men that are on active surveillance for the prostate cancer and their trying to make up their decision or their actually choosing to just monitor their prostate cancer rather then get definitive therapy, and we may be able to use the flax seed and monitor their PSA. So that would be the next direction.
Any closing thoughts, or take home message at this point?.
Well, you know that right now as far men who have prostate cancer the most important thing is to adhere to the ACS guidelines for cancer. I think you already mentioned the importance for weight management is one of the key issues and to eat a well balanced diet. At present, a lot of these functional foods flax seed is a functional food or single nutrients just need further investigation.
Great! Well thank you for being here with us today.
Well thank you so much!
If you have questions about anything you’ve heard today on Cancer Newsline, contact askMDAnderson at 1-877-MDA-6789 or online www.mdanderson.org/ask. Thank you for listening to this episode of Cancer Newsline. Tune in next week for the next podcast in our series.
Return to Cancer Newsline
© 2009 The University of Texas M. D. Anderson Cancer Center
1515 Holcombe Blvd, Houston, TX 77030
1-800-392-1611 (USA) / 1-713-792-6161