Dutasteride reduces PSA by 40% over 6 months

[janebob99]

This companion chart from data reported in Moore (2017) compares PSA, at baseline and at 6 months, comparing placebo to Dutasteride. This was a randomized, double-blind, placebo-controlled clinical trial.

The cohort included Low and Intermediate Risk men, GS-6-7, baseline PSA = 6-7, median age 64 y.o, N=42.

The average PSA increased by 8% in the placebo group , while the average PSA decreased by -40% in the Dutasteride group, over the 6 month period. The difference between these two percentage changes is 48%.

pubmed.ncbi.nlm.nih.gov/27871928/

[maley2711]

Are they claiming the reduced PSA reflected better treatment results....aren't there things other than cancer control that may explain the findings? For a long time, men have been warned of "false" PSA numbers when PSA is used to determine risk of PCa for a specific man.

[janebob99 in reply to maley2711]

Great question. I wondered about that, too. If the prostate gland itself shrinks while taking Dutasteride (which is true), wouldn't that alone cause the PSA to drop, even if one didn't have any cancer?

Conversely, infection, inflammation, and BPH can cause PSA to rise, separate from cancer. That's why PSA is not so great a predictor of PCa, compared to other measures (Gleason Score, PIRADS, AI, etc.).

That's why I was so excited to discover a randomized, double-blind, placebo-controlled trial in men with known PCa where they directly measured changes in the tumor volume radiographically with MRI in men taking Dutasteride or Placebo. Comparing the two groups over the same period of time, the tumor volume shrank by 31% on average while on Dutasteride, while it increased by 17% on average in the Placebo group, for a relative difference of 48 percentage points.

In the same study, the PSA decreased an average of 40% while on Dutasteride, compared to a PSA increase of 8% on average in the Placebo group, for the same relative difference of 48 percentage points.

Other studies typically report that Dutasteride reduces PSA by about 50% after a relatively short period of time.

PSA is secreted by both the cancerous part and the non-cancerous part of the prostate gland. I vaguely remember reading that PCa cells secrete more PSA per unit volume than the non-cancerous part of the prostate gland itself...but I could be mistaken about that. The PCa cells are more tightly packed together, so they may secrete more PSA per unit volume than healthy cells (which are less densely packed).

The observation that the PSA decreased by 40% on average, whereas the tumor volume only decreased by about 30% on average, suggests to me that a portion (perhaps a third) of the total PSA reduction (40%) is due to shrinkage of the prostate gland itself. Note: It has been reported that the prostate itself shrinks about 25-30% on average when taking Dutasteride.

This is strictly a hypothesis, however. More studies are needed.

[tsim]

Thanks for post, I'll forward along to my friend with prostatitis. His idiot Uro doesn't want to try it.

[janebob99 in reply to tsim]

Too many docs are scared of the black box warning in the USA (not in the UK).

[Gl448]

I had no sign of prostate cancer except for maybe the BPH I had in January 2022. The urologist prescribed me a 5α-reductase inhibitor and then five weeks later I had a TURP and negative biopsy.

Four months later in July I still had a low PSA, but blood and clots and more BPH signs. This time the biopsy from the TURP showed Gleeson 8, and a very aggressive prostate cancer (ductal) that had already gone to stage four metastatic.

I’m kind of thinking that black box warning has some merit, certainly enough merit that the doctor should’ve mentioned it to me.

[janebob99]

I'm sorry to hear about your diagnosis.

While all the studies seem to support the safety of using Dutasteride, on average, there will always be some % of men that react and behave differently than the average. Any treatment has risks. Hopefully, the risks are small, on average.

As my wife is fond of saying, "it sucks when you're the 1% ."