6 months ago
“clinician. I'm going to spend some time towards the end of this discussion on something that I also think is dangerously underappreciated, which is the interaction between a drug called finasteride. This is a drug that literally millions of men are taking for hair loss prevention, and how that drug interacts with our ability to interpret PSA correctly.”
“a class of drugs called five alpha reductase inhibitors. The most common of these is finasteride, but there's another one called dutasteride, and how they impact prostate cancer screening. So the use of finasteride has exploded in recent years, largely driven by men using it to prevent or treat hair loss.”
“many times on other podcasts, both in the context of hair loss and testosterone use. We've discussed the potential risks of finasteride and prostate cancer development elsewhere, but I want to have some dedicated sections here where I talk about that. So I want to focus on one specific issue, which is that finasteride, as far as we can tell from the data, does not cause prostate cancer.”
“physician doesn't know how to adjust for it. Now here's the mechanism. Finasteride blocks the conversion of testosterone into dihydrotestosterone or DHT in the prostate. And that reduction in local DHT also dramatically reduces PSA production.”
“As a practical matter, you can expect PSA to drop by about a third within six months of starting Finasteride and to be roughly cut in half by a year. That suppressed baseline persists for as long as the patient stays on the drug.”
“is simpler but equal. After about 12 months on finasteride, you should not expect your PSA to rise at all. The ongoing suppression from the drug should roughly offset the natural age-related increase in PSA.”
“finasteride should be treated as a serious, warning sign. And here's where I get concerned. Most general practitioners are not aware of this, it appears. A retrospective analysis of VA patients undergoing PSA screening found that men on finasteride were diagnosed with metastatic cancer at a rate more than double that of men not taking 5-alpha reductase inhibitors, 6.7% versus 2.9%.”
“face value, not realizing they needed to double them or more. The two groups had nearly identical PSA levels at the time of cancer diagnosis, about 6.8 versus 6.4. But once you correct for the Finasteride-induced suppression, the true comparison is more like 13.5 versus 6.4. Those are wildly different clinical pictures, and the physicians unfortunately missed it.”
“because even in men who were getting screened. The screening was rendered useless because the physician didn't understand how to correct the results. And I think that's especially urgent because many men are getting finasteride prescriptions from online clinics and then not even mentioning it to their primary care doctors because they don't think it matters.”
“can't account for it if they don't know the patient's taking it. So, if you're listening to this and you're taking finasteride, the onus may fall on you. Please be sure that you not only advocate for regular PSA testing, but make sure that your doctors know about every prescription, including and especially those that involve 5-alpha reductase”
“inhibitors, and ensure that whoever is interpreting your PSA understands both the drug and its suppressive effects. Again, finasteride does not appear to increase your actual risk of developing prostate cancer, but it can absolutely prevent your doctors from catching it on time.”
“a class of drugs called five alpha reductase inhibitors. The most common of these is finasteride, but there's another one called dutasteride, and how they impact prostate cancer screening. So the use of finasteride has exploded in recent years, largely driven by men using it to prevent or treat hair loss.”
“Most general practitioners are not aware of this, it appears. A retrospective analysis of VA patients undergoing PSA screening found that men on finasteride were diagnosed with metastatic cancer at a rate more than double that of men not taking 5-alpha reductase inhibitors.”
“including and especially those that involve 5-alpha reductase inhibitors, and ensure that whoever is interpreting your PSA understands both the drug and its suppressive effects. Again, finasteride does not appear to increase your actual risk of developing prostate cancer, but it can absolutely prevent your doctors from catching it on time.”
“sterile organ. And even with things like prophylactic antibiotics and preparation, infection rates from these biopsies ran between 5 and 7%. Which, of course, when you multiply that across the number of people that were having them is an enormous amount of morbidity.”
“very good method in the transrectal approach. Importantly, the transperineal method doesn't require prophylactic antibiotics, which is a meaningful benefit both for the patient and for the antibiotic stewardship more broadly as we face an era of antibiotic resistance.”
“a class of drugs called five alpha reductase inhibitors. The most common of these is finasteride, but there's another one called dutasteride, and how they impact prostate cancer screening. So the use of finasteride has exploded in recent years, largely driven by men using it to prevent or treat hair loss.”
As referenced on air, with the quote and the moment. Reported, not evaluated.
“But a trial in 2025 called the PRIME trial changed this. The study directly compared the full multi-parametric protocol, which is a T2 weighted image, a diffusion weighted image, plus dynamic contrast enhanced imaging against a stripped down contrast-free bi-parametric version that drops the contrast component all together.”
“So I'm talking about that PLCO trial. That's the study that the USPSTF weighted most heavily when it decided that PSA screening wasn't worth doing.”
“So we will put the figure from the 2016 letter to the editor in the New England Journal of Medicine in the show notes.”
“Once it was out there, a group of researchers went back to the PLCO data in 2017 and did something really clever. They mathematically accounted for the frequency of screening within the contaminated control arm, calculated amine and lead time, essentially how much earlier cancers were caught in men who were screened more regularly, and then imputed a mortality reduction based on earlier diagnoses.”
“we do this based on data from the prostate cancer prevention trial performed in the late 90s and early 2000s, as well as a follow-up analysis from 2005 performed by Ruth Ezioni and her colleagues.”
“we do this based on data from the prostate cancer prevention trial performed in the late 90s and early 2000s”
“as well as a follow-up analysis from 2005 performed by Ruth Ezioni and her colleagues”
“In fact, in a large study of 19,000 older men, those on finasteride who were cancer-free actually showed an average 2% annual decrease in PSA.”
“A retrospective analysis of VA patients undergoing PSA screening found that men on finasteride were diagnosed with metastatic cancer at a rate more than double that of men not taking 5-alpha reductase inhibitors, 6.7% versus 2.9%.”