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National Cancer Prevention Month: Lowering Prostate Cancer Risk With Stephen Freedland, MD, and William Aronson, MD

In honor of National Cancer Prevention Month, Dr. Stephen Freedland, Urologist at Cedars-Sinai Medical Center and Oncology Data Advisor Editorial Board Member, sat down with Dr. William Aronson, Professor of Urology at the University of California, Los Angeles (UCLA) and Chief of Urologic Oncology at the West Los Angeles Veterans Affairs (VA) Medical Center for a conversation about the multitude of factors under investigation for prostate cancer prevention. Dr. Freedland and Dr. Aronson discuss prostate-specific antigen (PSA) screening recommendations, medications being investigated, the roles of diet and exercise, and how they personally counsel their patients regarding prostate cancer prevention and risk reduction.  

Stephen Freedland, MD: Hello, I'm Steve Freedland, a Urologist at Cedars-Sinai Medical Center as well as the Durham Veterans Affairs (VA) Hospital in Durham, North Carolina. It's my great privilege and honor to be here today with my good friend and close colleague, Dr. William Aronson, Professor of Urology at UCLA and Chief of Urologic Oncology at the Greater Los Angeles VA Health System. Bill, it's great to have you here.

We're talking prostate cancer prevention in light of National Cancer Prevention Month in February. Things have shifted in prostate cancer where we're not just worried about prostate cancer, but we're worrying about aggressive prostate cancer and dying of prostate cancer. Let's maybe start with early diagnosis and PSA testing. What do we know about that in terms of trying to prevent ultimately dying of prostate cancer?

William Aronson, MD: Well, PSA testing is absolutely essential. We want to do it the right way. When folks stopped doing PSA testing from 2012 to 2018 based on the United States Preventive Services Task Force (USPSTF) recommendations, that was a terrible idea, and there was a lot more metastatic prostate cancer. We know that PSA screening is, for sure, useful. We just have to do it the right way.

Dr. Freedland: So, what is the right way?

Dr. Aronson: The US Preventive Services Task Force changed their recommendations, and now they're saying to consider it between ages 55 to 69—earlier for individuals who have risk factors — if patients are Black or those who have a strong family history. That's a reasonable starting point, but I think we need to go much further than that. We can have an informed discussion with the patient and discuss the pros and cons, what's termed shared decision making. And I think we should offer PSA screening for men who are older if they have an excellent 10-year life expectancy.

Dr. Freedland: And how about in that younger group? What are your thoughts about offering it to patients who are without high-risk features but are in their forties or early fifties?

Dr. Aronson: I think, again, it comes down to shared decision making. Certainly, if patients have a strong family history of lethal prostate cancer, if patients are Black, or if they have other risk factors—for example, if we know that someone is BRCA1- or BRCA2-positive—that's someone we need to be especially vigilant about. I think that there's some data suggesting that if your PSA is very low early on, your lifetime risk is lower. Again, I think that boils down to shared decision making. What are your thoughts on that?

Dr. Freedland: I agree. I mean, as I'm getting older, I got my first PSA in my mid-forties, having no risk factors. You put your money where your mouth is, so to speak. The question I always ask is, what do you do for yourself? It's easy to ask what you recommend, so let's throw it back to you, Bill. When did you start screening, or have you screened?

Dr. Aronson: Oh, I'm definitely screening. Probably around age 50 was when I got my first PSA, and it's been stable. I'm going to get another PSA today, actually. I certainly believe in vigilant PSA screening. There are lots of subtleties to it, which I think we need to discuss. I mean, is PSA a perfect blood test? Absolutely not. It needs to be looked at in a context of PSA trend over time, for example. If your PSA is elevated, the PSA density is a critically important number to know. There are a number of subtleties to it, but I think we should discuss PSA density. I think that's one important factor to discuss. I don't know if you want to get started with that and I can chime in.

Dr. Freedland: It's the concept that, as you said, PSA is not a perfect marker. One of the biggest reasons it can be elevated is just big prostates. I'm doing this in my practice for patients with elevated PSAs. I'll get a magnetic resonance imaging (MRI). If I see a big prostate but no lesions, I don't biopsy; I just follow it. Elevated PSA is a sign for me that we need to figure out why. It doesn't mean they have cancer. It doesn't mean they need a biopsy. It just means I need to figure out why they have an elevated PSA.

Dr. Aronson: Totally agree. I mean, for folks who are not familiar with PSA density, if you take the PSA and divide it by the prostate volume, that's the PSA density. Ideally we like to see it less than 0.15 ng/mL. For example, if a patient has a 100 cc prostate and their PSA is 10, then that PSA is less than 0.15, and we can feel a bit more comfortable with that patient. In my practice, I always look at the PSA trend over time, and if I'm interested in the volume, I like to do pelvic ultrasounds. I've found those to be very accurate, and it's simple on our end. It's a practice-based issue—whatever works well for you—but I have found those to be very helpful for knowing the prostate volume as well.

Dr. Freedland: I agree. I think early screening is crucial, but there are other things people could be doing. Are there any drugs out there that are FDA-approved or have shown efficacy for lowering the risk, and how do we use those?

Dr. Aronson: FDA-approved drugs, not that I'm familiar with. There was some interesting work done with finasteride and dutasteride, and it looked like they reduced the risk of having non-aggressive prostate cancer. But because of some of the issues with the data suggesting there may be an increased risk of more aggressive prostate cancer, it wasn't approved by the FDA. That issue is debatable. I certainly use finasteride for patients who have an enlarged prostate to help them urinate better if they're having lower urinary tract symptoms. But there are no medications that I know of that are FDA approved.

Dr. Freedland: When you put a patient on finasteride for their enlarged prostate and their urinary issues, do you talk to them about the prostate cancer risks and the pros and the cons, or not?

Dr. Aronson: What I talk with them about is I let them know that it's going to cut their PSA in half. We have to take their PSA once they're on finasteride and divide it by two, and then remember, if we're going to screen for prostate cancer while they're on finasteride or dutasteride, we have to multiply their PSA times two to get the actual PSA. I think that is well worth knowing. I actually don't discuss with patients that issue of potential increased risk of prostate cancer if they're on finasteride. Do you do that in your practice?

Dr. Freedland: I do. As physicians, as surgeons, we live by anecdotes, right? I remember a patient who was prescribed finasteride by another provider who clearly hadn't given that warning. The person went and read the package insert word by word, line by line. He came to me and was livid at the other urologist. We spent a lot of time calming that patient down. It's just stuck in my memory, so I like to tell them the good and the bad before they read it online somewhere and then get mad at me for not having told them.

Dr. Aronson: Fair enough.

Dr. Freedland: So, are you using these drugs even though they're not FDA-approved? Have you ever used them for preventing prostate cancer in patients?

Dr. Aronson: Definitely not, but I'm going to swing that one back to you. Are you using statins to prevent prostate cancer?

Dr. Freedland: I am not. There's some data, as you know well, about statins preventing more aggressive prostate cancer. It's not the same level of evidence we have with dutasteride and finasteride. They're not randomized controlled trials; they're observational studies. I think some of the mechanisms of statins are probably controlling cholesterol, which we're going to hear about from you and a lot of the diet stuff that you do.

One of the biggest questions I get is, "Well, what can I be doing? I don't want to take pills." I'm here at Cedars-Sinai, so I'm in Los Angeles and Beverly Hills. Nobody wants to take pills. Everyone wants to be on the perfect diet, the perfect lifestyle. I get that question a lot, so let me turn it over to you. You're one of the world's foremost experts in understanding diet, lifestyle, and their impact on prostate cancer. What do we know? And then what do you tell your patients?

Dr. Aronson: Just to be crystal clear on it, we do not have the prospective randomized trials to support what we're talking about right now. We can talk about our understanding of the literature, and based on both of our many years of experience with this, what we think the data points to. First thing I'll always say is a heart-healthy diet. When patients want to know what to do to prevent prostate cancer, I would shift gears in their thinking to, what's going to be most likely to kill men as we age? And the answer is heart disease. In that regard, it's a healthy diet and regular exercise.

Dr. Freedland: How do you define a healthy diet?

Dr. Aronson: For a heart healthy diet, I'll just suggest that patients go to Google and look up the American Heart Association recommendation. Obviously it's more vegetables, more brown rice. We can get into more details about that. There are lots of things that I have strong beliefs about based on data. Then patients can also look up exercise for heart health. There are specific societies that have recommendations for that.

If patients want to read about it further, I like to refer them to the Prostate Cancer Foundation website, pcf.org, where they can really get more of the information that they need. It will give them specific recipes as well. This is a starting point. If they push me further, I'll talk with them about it more. I think some of the best data is on lycopene; the red color in tomatoes has the antioxidant called lycopene in it. There are some nice preclinical mouse studies and human studies on lycopene. I could go on and on and on. What do you suggest for patients?

Dr. Freedland: So, what I tell patients—and I'd love to hear about your research, because you've done a lot of research on this, and I think we're all colored by our own research in this space—is because there is no Level 1 evidence, there's nothing that I can point to that definitively will have a benefit. We live in the US, and patients want a soundbite. They want one or two pieces of advice that they can follow. The one thing I try to focus on is giving up simple sugars—cookies, cakes, candies, soda. Basically, what I'll say is I do a lot of nutrition research. I learned it from you; you do a lot of nutrition work. We've talked, and I've talked to other people, and nobody is recommending simple sugars as a good thing. That's one thing that probably we can all agree shouldn't be in the diet.

After that, it's the wild, wild west, and everyone has opinions. If they're really going to push me for advice, I tend to recommend more towards low-carb, keto, or a whole-food plant-based diet. I'm very careful to not just say plant-based, because cookies could be plant-based. A whole-food plant-based diet, I think, is perfectly healthy as well. I'd love to, at some point, do a randomized trial of whole-food plant-based versus keto. My guess is we're not going to see a heck of a lot of differences in terms of prostate cancer. We think they're both pretty good, but I focus on the simple sugars. But if someone really pushes you, what do you tell them? And then tell us a little bit about the research you've been doing. There's some interesting stuff there.

Dr. Aronson: Happy to, but just to kick it back to you one more time, I think that what we do know is that men who are obese are more likely to get aggressive prostate cancer. In that regard, I see you as the expert, actually, in this area. What you're really getting at with your approach is weight loss. That's an important factor. Is it time for semaglutide (Ozempic®) for some patients? I mean, who knows?

Dr. Freedland: You know, I'm very intrigued by Ozempic® and the other drugs. There are multiple now, but I agree. I do think weight loss is important. There's actually increasing data that smoking is linked with aggressive prostate cancer and fatal prostate cancer as well. That's another thing; there are not a lot of reasons to be smoking, and we can probably add aggressive prostate cancer to that list as well. Then the exercise, I do think, is an important component out there as well. Again, when you're really pushed, what are you telling people and what are you finding in your research?

Dr. Aronson: The first thing I do tell people, again, is just to go back to the lycopene. I think that's something they can easily do. They can eat more tomato paste and tomato sauce products, though they do have to be careful of the salt if they have hypertension. Then when you eat those products and you include olive oil, which inevitably accompanies those, that's also one of the healthy fats. I think that's something to really let patients know about.

With regards to our research in dietary fat, the real enemy in my mind is the omega-6 fatty acids. There are three types of fat. There's saturated, monounsaturated, and polyunsaturated. The healthy fats like olive oil, the monounsaturated fats, are going to be a favorable fat choice. But the polyunsaturated fats, there are two types we think about, the omega-6 and the omega-3. It's those omega-6 which are predominant in the American diet. You get it from corn oil. When you use corn oil, and actually soy oil, you're getting the omega-6 fatty acids. It's in baked goods, it's in cookies, it's in fried foods. You're probably getting it in meat and in corn-fed animals.

What we see in our lab is if you grow a human prostate cancer under the skin of a mouse and you give them corn oil to eat, the more corn oil they eat, the faster that cancer grows. We see that over and over and over again. When we lower the corn oil, we also see a reduction in the growth. We're not talking about prevention right now, although we do have a prevention study which we did in mice who develop prostate cancer. Again, if you lowered the corn oil, you saw decreased development of prostate cancer in these genetic mouse models. We have some human studies, which I think are compelling as well, that we're writing up right now and hope to have published within the next month or two.

The other issue which is important, in my view, is increasing fish intake. With fish, you're getting the more favorable omega-3 fatty acids. The easiest way to get that in the diet is with salmon, though sardines also provide the omega-3. With the salmon, certainly wild-caught provides more of the omega-3. But even when you buy farm salmon, you're still getting the omega-3 fatty acids in there. Then there's the debate about fish oil, taking a fish oil supplement. I think there may be value there as well.

Dr. Freedland: Do you recommend taking fish oil supplements?

Dr. Aronson: I'm not yet recommending fish oil supplements. I think we can discuss the data with the patients and they can make their own determination, but we do not have strong prospective randomized trials showing that fish oil is beneficial. There is some data to the contrary, though I think the data has been well-proven that fish oil does not increase risk of prostate cancer. Again, I think it's a dietary supplement that patients can consider using on their own, but I don't tell all my patients to take fish oil.

Dr. Freedland: We're almost out of time, so quick yes or no—are there any supplements that you do recommend?

Dr. Aronson: No, but I discuss supplements with patients. I can tell you what I don't recommend. There was an excellent study done on selenium and vitamin E. Folks thought that those might prevent prostate cancer. Individuals in the group that got the vitamin E actually had an increased risk for prostate cancer, so I think that's some good hard data that we have.

Dr. Freedland: I would love to continue the conversation. I think we're out of time, but I'd love to have you when those results that you're alluding to are published. I'd love to have you back and talk more about that. But I think to sum up, in terms of preventing prostate cancer, early screening is probably still our best bet. We have drugs, but they're not FDA-approved and they're not widely used. We all want to believe that diet and exercise have a role. We're still debating exactly the best way, but I think avoiding obesity, limiting smoking, and getting some good exercise is probably the way to go.

Dr. Aronson: Totally agree.

Dr. Freedland: It's been a pleasure to have you on, Bill, and we look forward to having you back.

Dr. Aronson: Thanks, Steve.

About Dr. Freedland and Dr. Aronson

Stephen Freedland, MD, is Director of the Center for Integrated Research in Cancer and Lifestyle and Associate Director for Education and Training at the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute in Los Angeles. He also is the Warschaw Robertson Law Families Chair in Prostate Cancer and a Professor in the Department of Urology at Cedars-Sinai. He also holds a Staff Physician appointment at the Durham VA Medical Center in Durham, North Carolina. Dr. Freedland has published over 700 articles and served on numerous American Urological Association and American Society of Clinical Oncology guideline panels for prostate cancer. His research interests include the role of diet, lifestyle, and obesity in cancer, cancer health disparities, and cancer risk stratification.

William Aronson, MD, is a Professor in the Department of Urology at UCLA Health. He is also Chief of Urologic Oncology at West Los Angeles VA Medical Center and Chief of Urology at Olive View-UCLA Medical Center. Dr. Aronson specializes in translational research on nutrition in prostate cancer, including the roles of nutritional components such as dietary fat, omega-3 fatty acids, green and black tea formulations, and lycopene in the prevention and treatment of prostate cancer. He has led numerous clinical trials focusing on nutrition in prostate cancer and has published extensively on these topics.

For More Information

American Heart Association (2023). The American Heart Association Diet and Lifestyle Recommendations. Available at:

https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/aha-diet-and-lifestyle-recommendations

Prostate Cancer Foundation (2023). Prostate cancer diet. Available at: https://www.pcf.org/patient-resources/living-prostate-cancer/prostate-cancer-diet/

Transcript edited for clarity. Any views expressed above are the speakers' own and do not necessarily reflect those of Oncology Data Advisor. 


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