Antidiabetic medication and PSA, recent study

"Association Between Antidiabetic Medications and Prostate-Specific Antigen Levels and Biopsy Results" (November 6, 2019)

jamanetwork.com/journals/ja...

"RESULTS The cohort of 564 666 men (median [range] age, 65 [40-79] years) consisted of 4583 men initially exposed to metformin, 1104 exposed to sulfonylurea, and 978 exposed to insulin who were age matched with unexposed men (1:5). Exposed men had lower median (interquartile range) PSA levels before starting antidiabetic medications compared with unexposed men (1.2 [0.7-2.5] vs 1.6 [0.8-3.2] ng/mL). After accounting for baseline differences, PSA levels did not vary from those of unexposed men following exposure to antidiabetic medications. Frequency of PSA testing was higher for those receiving metformin (rate ratio, 1.07; 95%CI, 1.06-1.09) and sulfonylurea (rate ratio, 1.06; 95%CI, 1.03-1.08) but was lower for those receiving insulin (rate ratio, 0.79; 95%CI, 0.77- 0.81). Likelihood of biopsy after elevated PSA was lower among men receiving metformin (odds ratio, 0.87; 95%CI, 0.80-0.96) and insulin (odds ratio, 0.83; 95%CI, 0.74-0.93). There were no differences in prostate cancer detection at biopsy, regardless of PSA levels that triggered the biopsy.

CONCLUSIONS AND RELEVANCE This study’s findings do not support the hypothesis that the inverse association between diabetes and prostate cancer is mediated through antidiabetic medications lowering PSA levels to mask prostate cancer. They do suggest potential detection bias due to fewer biopsies among men receiving antidiabetic medications, which may explain the lower prostate cancer risk in men with diabetes."

[2dee]

I was on Metformin for a few years before asking doc to approve stopping. Didn't like side effects and size of pills.

About a year later that experience did nothing I could judge to stop a rapid onset of stage4 PCa.

Remember though there are separate SOC for prevention and later very different therapy for treatment.

2Dee

[kapakahi]

I'm not sure what this means - I guess I'm stuck on "mediated through" - is this saying that metformin lowers PSA, thus potentially masking prostate cancer because PSA is low enough to not trigger a biopsy?

[Hidden in reply to kapakahi]

My understanding is that it claims the exact opposite.

This was my reason for posting it.

It directly contradicts what is already trusted as valid.

[Ahk1]

I am confused. Please elaborate on this. I have a rising psa after failed RP and SRT. I am looking to use metformin and avodart to tryto slow the psa which is currently at .74 with a good PSADT. Dr Myers recommendation for his patients to take metformin and avodart. Is your experience different than this based on this articles or other research? Thank you

[Hidden]

I don't have any long experience in this, but I am an interested party as I take (precautionary after RP) half doses of Avodart and Berberine (1 Avodart every other day and daily 400mg of Berberine with lunch).

My understanding is that until now it was believed that these drugs mask PSA and after extended use (years) the reading of the PSA test should be doubled (or even more) to account for this masking effect. The above mentioned study challenges this belief as not being true.

My own hypothetical thinking says that when the prostate is in place the registered PSA is the sum of the cancerous plus the benign. If any of these drugs limit the latter, than the reading is really skewed towards lower values, not compatible with those of the general population.

Now we come to the point that interests us lacking the prostate: Is there any benign PSA left behind after RP that can be masked and should be accounted for?

I don't have an answer to this, just keep it at the back of my mind as a loose possibility.