Host Dr. Shannon Westin and guests Dr. Bill Aronson discuss the article "High Omega-3, Low Omega-6 Diet With Fish Oil for Men With Prostate Cancer on Active Surveillance: The CAPFISH-3 Randomized Clinical Trial" and how Omega-6 are predominant in the American diet while the study significantly lowered the intake of Omega- 6 fats.

TRANSCRIPT 

Dr. Shannon Westin: Hello everyone and welcome to another episode of JCO After Hours, the podcast where we get in depth on manuscripts published in the Journal of Clinical Oncology. I'm your host, Dr. Shannon Westin, GYN Oncologist by trade and one of the grateful Social Media Editors of the JCO. And I am very excited to welcome a special guest today, Dr. William Aronson. He is professor of Urology in the UCLA Department of Urology, the Chief of Urology at Olive View UCLA Medical Center, and Chief of Urologic Oncology at the Veterans Administration West Los Angeles.

Welcome, Dr. Aronson.

Dr. William Aronson: Thank you, Shannon, and delighted to be here.

Dr. Shannon Westin: We are so excited to have you discussing your manuscript, “High Omega-3, Low Omega-6 Diet With Fish Oil for Men With Prostate Cancer on Active Surveillance: The CAPFISH-3 Randomized Clinical Trial,” which was published in the Journal of Clinical Oncology on December 13, 2024.

So let's get right to it. First of all, you know we have a very mixed audience, so can you just level set for us and speak about the population you studied in this important trial - that low risk, favorable, intermediate risk prostate cancer. How common is that? How is it defined? That would really help.

Dr. William Aronson: I would say about 50% of the patients that we diagnose with prostate cancer either have low risk disease or what we call favorable intermediate risk disease. So when the pathologists look at the cancer under the microscope, they assign what's called a Gleason grade. Grade 3 is the slower growing type of prostate cancer, grade 5 is the fastest growing type, and grade 4 is somewhere in between. So a low risk group would be only the grade 3, the slower growing type. And the favorable intermediate risk group would actually be the grade 3+4, which means they mostly see the low risk type in there, but they also see the slightly faster growing type, grade 4. So this is what we typically see. We see these patients on a very regular basis when they're newly diagnosed with prostate cancer.

Dr. Shannon Westin: Okay, got it. And then can you walk us through just what the management options are typically for this patient population?

Dr. William Aronson: So typically for what we call the low risk group, the patients with a low PSA and only that grade 3 type, slower growing type of prostate cancer, the standard recommendations are active surveillance. So typically, we'll periodically monitor these patients with PSA blood testing and periodically do prostate biopsies depending upon the patient's other medical problems.

Dr. Shannon Westin: So I think it would also be really helpful just to understand what your typical management options are for this patient population.

Dr. William Aronson: So for patients with low risk prostate cancer, they only have the Gleason Grade 3+3 with a low PSA. The standard practice is observation. And so these men will periodically see them and measure their PSA values. And periodically, they'll undergo prostate biopsy to make sure they're not getting progression of their disease.

For men with favorable intermediate risk prostate cancer, that's a little different. In some practices, the patient and the urologist will decide to do active surveillance. In other scenarios, these patients will definitely elect treatment, either with radical prostatectomy or radiation therapy or other treatments that are available.

Dr. Shannon Westin: So your manuscript notes that there was a high level of interest in dietary supplements and approaches among patients with prostate cancer that do elect for active surveillance. Prior to the results of CAPFISH-3, did we have any data to support those types of recommendations?

Dr. William Aronson: We actually don't have any long term prospective randomized trials that support that recommendation. There have been a number of very interesting epidemiologic studies, for example, suggesting maybe a plant-based diet might be helpful. Or a number of other studies suggesting maybe more tomato-based products like tomato sauces or tomato paste may be helpful. But no prospective longer term randomized trials that were positive.

Dr. Shannon Westin: Okay, that makes sense. So what led you all to explore the high omega-3, low omega-6 fatty acid diet in this trial?

Dr. William Aronson: After our initial omega-6 studies, we subsequently did some studies where we raised the omega-3 from fish oil and lowered the 6, looking at a more favorable ratio of the omega-3 to omega-6. And once again, we found that in our animal models, there was a significant delay in progression of prostate cancer. That then led us to perform a clinical trial. It was a short term trial in men prior to undergoing radical prostatectomy. And in these men, they were randomly assigned to one of two groups, either a western high fat diet or a low fat diet with fish oil. And we found after just four to six weeks, a significant change in the Ki67 level in their radical prostatectomy tissue. And Ki67 is actually a strong indicator of prostate cancer progression, spread, or even death from prostate cancer.

Dr. Shannon Westin: Well, and I think that leads us really nicely into the design of the current study. So why don't you walk us through how CAPFISH-3 was designed. And you've already spoken a little bit about your primary endpoint.

Dr. William Aronson: <span lang="EN" xml: