PSA doubling

[Blair77]

How does the PSA doubling time change? I thought it was an equation that told you how fast your PSA was rising? When I plugged in my husbands number from April to May it said the PSA was doubling every 3 months. Then I plugged in May to June and it said doubling time was 1 month. If the doubling time changes what’s the point of it?

[FCoffey]

Doubling time changes because the cancer changes. It also changes because no measurement is perfect. I've taken PSA tests 2 days apart and seen more than 10% differences.

Drinking alcohol, sex, and other activities can cause PSA to rise temporarily in men who still have their prostates.

The formula most doctors use for doubling time is wrong. The right way to compute doubling time is to take a series of measurements and use a math/statistics technique called least squares to find the most likely doubling time. But most doctors are ignorant of math and statistics, so they use the simple but wrong formula.

In most cases, prostate cancer is slow. Calculating the doubling time over many months or a year can give some idea of the rate of progression, but just an idea. PSA is only a proxy for prostate cancer, it isn't a direct measurement of cancer.

[pjoshea13]

The PSA doubling time [PSADT] is useful for estimating how fast a tumor is growing. A shortening PSADT is worrisome, as is a PSADT of 3 months or less.

-Patrick

[Tall_Allen]

To be valid, you need at least 3 points in time, and all values must be over 0.1.

[Daddyishealing]

I don't have the answer to your question, but when my dad's psa kept going up, he demanded immunotherapy PROVENGE, which he wasn't eligible before. He got through with almost no side effects except some tiredness. That was to his advantage because rt before starting PROVENGE his psa went down. So sending you light love and hugs

[Blair77]

Thanks, when we asked about Provence we were told “ no” by our oncologist. He didn’t explain why. I’m not sure why someone wouldn’t be eligible for it.

[Patrick-Turner]

Psa doubling time indicates the rate of increase of Psa. Once upon a time in 2012, my Psa had gone down to 0.8 after EBRT and 2 years of ADT. Treatment was deemed to be finished, and ADT was halted. But then Psa rose to 8.0 after 8 months. The rate of increase was not linear. The first Psa at 3 months after stopping ADT rose, but did not double, then in another 3 months it nearly doubled, then nearly doubled again in another 3 months and I switched from urologist to oncologist becauser urologist had failed to fix my Pca problem and Psa was back to where is was at time of attempted RP in 2010, which could not continue because Pca had spread outside the capsule and was adhering to the network of nerves all around the prostate gland. Urologist had been doing 2 ops a week for many years, and I was one of the 1% of patients where he thought he could not fix me by removing PG. Since 2012, I re-stated ADT, Psa quickly went to 0.22, but crept up by doubling each year, but then by 2015, rate of Pca increase quickened and doubling time reduced, so I had some "salvation" radiation to PG and took cosadex because ADT alone had failed to hold down Psa. The extra RT seemed to stop Pca at PG, but cosadex only lasted 6 months, so in 2017, I went to Zytiga which gave me only 7months.

The exact calculated rate of Psa does not matter but in many cases like mine the Psa remains suppressed only for a short time, and then it zooms up again after each treatment fails after some time. I have known guys who have survived 25 years after

diagnosis to before the time to begin chemo therapy, and others who have gone from diagnosis to RP then RT then ADT then chemo all withing 3 years, and this fellow now had only 6 months of Psa reduction and he faces stronger chemo and he shows all the signs of not having anything kill his Pca and he will pass away soon.

I was diagnosed in 2009 with gleason 9+9 which just means I had Pca that had very high

chance of killing me within 10 years. I had a low amount of Psa but a high amount of cancer, and Pca probably began and could have been detected in 2005 at a time when detection methods were primitive.

Now, my Pca has spread to multiple bones, too many spots of cancer on scan to count, and I must start chemo soon and maybe have Lu117. The metastasis of Pca is different for different men, no two Pca case histories are ever going to be the same, so what works for one man may not work for another, and the Pca spread may have occurred in me way back in 2006. My Pca is slow growing, and its is possible spread spots ( metastasies ) were present, but undetectable from 2006 to 2017 when the they got large enough to be seen in Mpsa gallium 68 scan, which detects Pca 2 years earlier than when a normal CT scan would see. So in many cases, docs do not think Pca has spread, but in fact it has, and despite ADT and RT etc, but it takes time to be seen in scans.

My oncologist was more horrified by my bone scans than I was because my reading told me what was likely so I expected the same rotten luck to continue, and it has, and probably, despite treatments planned before next Xmas, the Pca will kill me within 5 years.

Psa does not necessarily give an accurate indication of disease presence because like all cancers, Pca mutates over time, and some Pca does not produce Psa, and Lu117 is useless, and chemo also may only kill a few of the Pca cells so for each tratement there

are survivor cells which defeat whatever doctors try to use, and then the Pca wins.

The only ray of hope is immunotherapy, Provenge is one, but extends life by only a short time but in UK recently a couple of guys have had near remission for new treatments invented there. The trouble is that for the vast majority of men with Pca, no such therapy is available and will not be available until another 5 years of trials to make sure treatment side effects are known, minimized, and treatment delivery method is optimised.

I might be able to have my cancer spots analysed to find out what chemo works best.

but this is super expensive. So is Lu117, $40,000 for 4 injections plus other $$$.

After awhile, the doubling time means little, you just hope the docs react in time to get Psa to start reducing, and not increase, but keeping Psa down forever seems quite impossible.

But meanwhile, although I know my days are numbered, I am trying to lve well at 71, and I am continuing to cycle 220km a week, regular as clockwork, and I don't have coffee, alcohol, red meat, and I do eat many green vegetables, I have remained fit for this "journey" that was forced on me by Aunty Destiny, ie, but the function of my DNA over which I have zero control.