These two Kaplan-Meier plots compare Dutasteride (0.5 mg/day) to Placebo in a randomized, double-blind trial from 2012 of 187 men who have progressed to PSA Failure.
In the upper plot, Dutasteride increases the Doubling Time from, for example, 9 months to 18 months (factor of 2X).
In the lower plot, Dutasteride increases the Time to Disease Progression (intent to treat) from, for example, 9 months to 18 months (factor of 2X).
Dutasteride reduces DHT levels by more than 90%, and DHT is what "fuels" prostate cancer growth. Plus, it treats Male Pattern Baldness!
In the past you indicated your taking Dutasteride reduced your PSA level by approx. 50%, pretty much what any urologist knows, and takes into account this misleading 50% drop in monitoring cancer progression, and in today's graph you show it reduces doubling time 50%;
Yes, I still have cancer. I will have a new MRI in about 1 month, and I will find out if my 1.3 cm long tumor has shrunk on Dutasteride monotherapy.
I maybe misspoke about the graph I posted. The correct interpretation is that Dutasteride increases the PSA doubling time by about 2X, compared to placebo.
I'm curious...why do you think Dutasteride reduces doubling time by 50%?
I’ve been taking Dutasteride since 2015, it was prescribed by Snuffy Meyers, part of his triple hormone therapy - Lupron/Xtandi/Dutasteride. Snuffy said it limited testosterone starved cancer cells from converting LDL cholesterol into DHT, a highly potent form of testosterone.
I take 0.5 mg once a day, that was per Snuffy Meyers. My current PCa specialist, Dr. Sartor always reviews my medications during a visit and has not changed it or told me to stop. In fact he hasn’t changed anything that Snuffy prescribed for me that I continue to use. I can’t speak about the benefit for CR or HS only that I’ve used it when I was HS for about 6 years and continue now that I’m CR for about 2-3 years.
I'm not aware of any serious side effects of Dutasteride. It's used primarily by men to fight male pattern hair loss (baldness). It just has this really neat way of reducing DHT by 95% while simultaneously increasing testosterone by 20%. Since PCa feeds directly off of DHT, not testosterone, this is the reason that Dutasteride (0.5 mg/day) reduces Prostate Cancer by 40% [23% to 51% in three large studies].
15% of non-malignant men don't respond to Dutasteride, and about 30% of men who do have PCa don't respond, as well. But, your odds are 70% that you will respond favorable to Dutasteride.
One study used 3.5 mg/day dosing, and I believe that it's available up to 5 mg/day. But, 0.5 mg/day is the universal starting dose. My PSA dropped from 10 to 3.3 over 3 months on Dutasteride monotherapy (no ADT).
Unfortunately, there is a black box warning. Here is a discussion about that:
There is a black label warning on Dutasteride (0.5 mg/day), because one study reported a small increase in the risk of having high-grade prostate cancer (i.e., large tumors).
I have two papers (there are likely more out there) that debunk this report. They call for a removal of the warning label.
There are two different biases that caused the higher incidence of high-grade tumors.
One is a “detection bias”, that relates to the fact that Dutasteride shrinks the prostate’s volume by 25-50%. So, the probability of a biopsy needle increases as the size of the prostate decreases, assuming the number of tumors remain the same. One of the papers (Cohen, 2007) did a calculation of how much the probability of hitting a large tumor (high-grade tumor) increases when the prostate shrinks, and the calculation predicted the same magnitude of increase in the incidence of high-grade tumors in men on Dutasteride.
The other bias is a “diagnosis bias”. In a large study of Veterans at VA hospitals, they also found an increased risk of higher-grade PCa for men on Dutasteride. The explanation for the increased rate of larger tumor detection is related to the fact that the PSA drops by about 50% (or more) after a few months of being on Dutasteride. For some men, the PSA dropped below the threshold for getting a biopsy (e.g., PSA = 4). So, those men decided to not get a biopsy. But, some of those men eventually got PCa later on (as their PSA continued to rise even on Dutasteride.) The fact that these men weren’t screened (because of their low PSA values), meant that they eventually ended up with higher-grade (larger) tumors, as compared to men who got early screening. The paper by Sarkar (2019) explains this “diagnosis bias”.
Both types of biases explain why the black label warning was originally applied. But, the effect has since been debunked because of both the detection bias and the diagnosis bias.
Recent studies with large numbers of men support that Dutasteride reduces prostate cancer rates across all risk groups. These are:
ARIA (2004) N=4325 51% reduction in PCa;
REDUCE (2010) N=8231 23% reduction in PCa;
CombAT (2011) N=4844 40% reduction in PCa.
The average reduction in PCa is 38%.
If you send me an email to janebob99@lobo.net with a note, I will send you papers and plots on Dutasteride.
My testosterone continues to remain stable at <20, so not sure that it increases testosterone and not sure that increased testosterone is desirable in advanced disease unless you’re doing BAT.
In the castrate-resistant regime, higher levels of testosterone appear to be very protective. BAT therapy is an extreme example of this. The high T during periodic BAT resets the cancer cells to be HS again, and then Lupron ADT can do its job.
Prostate cancer specific mortality probability versus time
I've been on Dutasteride for 3 months (no ADT) and my PSA dropped from 10 to 3.3 during that time. I'm newly diagnosed 4 months ago with T3a and some ECE. PSMA-PET is negative outside of the prostate. GS 7 (3+4 in 4 cores, 4+3 in one core). So, I'm still HS.
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Psa doubling time 
Doubling Time Question
