In this health video you will learn about the gold standard selenium trial and how well it did.
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Dr. Mark Whiacre: Paul, regarding this Nutritional Prevention of Cancer trial—the trial that started with Dr. Larry Clark and Dr. Gerald Combs at Cornell University in 1983 and was published in the Journal of the American Medical Association in 1996—about how many individuals were included in that trial? It was a landmark trial, you mentioned, and a tremendous effort. About how many individuals and why was it done blinded? Mr. Paul A. Willis: It’s called a gold standard clinical trial by National Cancer Institute. And that terminology refers to the fact that it is randomized; the selections of people come from a random group, so it’s not slanted any one direction. It’s randomized; its placebo controlled—meaning that there’s going to be an intervention agent, selenium in this case, and then a placebo. It’s double blinded, which means that, as a clinician, if I’m giving you—as a clinician, if I’m giving you either placebo or the intervention agent, you don’t know which one you’re getting and I don’t know. So it’s double blinded, which means that it’s going to be less slanted. So, we’re protecting the gold standard, that it’s designed in a way that leaves no perceived bias already in the trial. The fourth thing is that it’s a long-term trial. It’s not something that runs for 30 or 60 days; but this trial, in fact, ran 14 years. It was unblinded early. There was just under 1400 participants, men and women of various ages, randomized in the trial—it was 1395, I believe. It was a 14 year trial. It was unblinded early—it was stopped because it goes through medical review during the trial. The safety committee is continually looking at the data that is blinded, just to make sure that no safety effects are going astray. Although it showed a zero effect on selenium supplementation for skin cancer, which was the primary inpoint, they began to see a clinical result in the prevention of colon, lung and prostate cancer. And therefore, once this was predominantly seen and proven by the data, it’s no longer ethical once you know that an intervention agent is preventing cancer—it is no longer ethical to keep individuals on a placebo. We have a placebo effect because it’s unproven, the intervention agent is unproven. But once we see the data is showing that there is a clinical effect or prevention of a disease, then it is unethical to keep anybody on a placebo once you know that effect. So the trial was unblinded in 1994, and then peer reviewed and published in the Journal of the American Medical Association in 1996, which reported the 50-63% reduction. So a gold standard trial is really designed to give the confidence when the data comes out that there is no bias and there is clear demonstration of a positive effect, if that’s what it shows. Dr. Mark Whiacre: And it sounds like the newer trial that are on-going today—and I know that you can’t say a lot about those because they’re still on-going—but it sounds like they’re being conducted in a similar fashion. Mr. Paul A. Willis: Exactly the same fact—gold standard clinical research. Once they began— and they run from three to 13 years, depending on the specific trial and the number of participants in the trial—here again, they’re randomized, they’re double blinded, and they’re placebo controlled. And we’re often asked, what the status of the research is, and we can honestly say that we don’t know. And we’re not supposed to know and that’s why they’re blinded. But there are safety groups and safety committees within the trials that are watching the safety and the ethical side of it, and much like the Nutritional Prevention of Cancer, would be unblinded and stopped if they began to show immediate, positive results. So, we’re glad to be a part of the gold standard of clinical research, and with the remaining research committee, we just are patient to see the results of those trials.