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Posted 2/10/2011 10:58 PM (GMT 0)
In calculating PSA doubling time, would you go from post surgery numbers to present, or would you take the previous 6 months, or some period of time ?

I am 22 months post op.  I have gone from 0 to .02.  If I use 22 months, it is a very slow doubling time.  If I use the last 6 months, it is a faster rate.

Just finished reviewing the 9 decsions before electing radiatiin therapy after RP, and watching Snuffy Myers video.  Both talk a lot about doubling time as a key decsion factor.

Thanks.

Goodlife

Posted 2/10/2011 11:04 PM (GMT 0)
Okay...from your other post now I understand what you are getting at.

I don't know the answer to your question exactly. In my own case the 1st years numbers gave me a whopping 18 month doubling time. But the second year came in at 6 months. Don't really understand why this happened. But the oncologist I am with states he likes to use the last 3 measurements that are spread apart at least 3 months each.

So based on that, I would use the last 3 readings you have to calculate your current doubling time.
Posted 2/10/2011 11:10 PM (GMT 0)
I agree with Les on this one, that's how my doctor calculates the doubling rate.
Posted 2/10/2011 11:20 PM (GMT 0)
Yes, you need more data points, and use a calculator online. It is not a matter of simple math, because PSA increases exponentially, not linearly. You can get a rough idea without one, but to see what it really is, use a calculator. The formula, with two values, is:

td = (ln 2 x t) / {ln [PSAt] – ln [PSAinitial]}

and who wants to bother with all tht.



You can't calculate a doubling time from zero, since zero doubled is zero. So the calculators require you to put in a nonzero starting point. The more data points you have, the better the estimation of your particular PSA kinetics, but at some point you have to make a decision. Like in my case, I couldn't wait around for more tests, or I'd have been past the point where SRT was likely to help.
Posted 2/11/2011 4:01 AM (GMT 0)
Les,

Thank you for your help.

As a Gleason 9, i have decided that I really have to try and stay ahead of it. G 9 doesn't act like 6's and 7's all the time.

After surgery, my PSA was 0, so I didn't worry about adjuvent until I conquered incontinence. As I watch my PSA creep up ever so slowly, I now am very close to commencing with what I will call delayed adjuvent, but may well be called early salvage.

So, I am in the process of trying to calculate the right time. Based on some of the studies, I conclude that starting rad prior to .2 is good, so why wouldn't commencing prior to .1 be better ? The problem is that there is so much data, so many studies, and they certainly don't all agree. Add in doctor opinions, HW opinions, and a plethora of other feelings, and it becomes a pretty major calculation that I have decided is more of a gut feel than a scientific one.

I am gathering as much info as I can, seeking multiple medical opinions, reading as much as I can, and ultimately, I will decide if and when.

I do appreciate Healingwell and the guys on here who have been down this road before me.

Goodlife
Posted 2/11/2011 4:24 AM (GMT 0)
goodlife, based on what 2 medical and 3 radiation oncologists told me, once bcr is confirmed, there is no gain by waiting for the number to reach some milestone, i.e. .2, .5, etc. this is why mine started at around .16 if i remember correctly. for me, the number wasn't going to be going down, only up, so the thinking was the most effective route was at the lowesst number. but as you know, so many opinions even on that statement alone. with your stats, i would feel the early side would be better than the later side, you already have a lot stacked against your stats in my opinion.
Posted 2/11/2011 1:44 PM (GMT 0)
Goodlife, I agree with David,

You are a gleason 9 and that is a very aggressive disease and needs to be treated aggressively. The clinical trial I am in right now is attempting to solve the age old question of radation with HT vs. radiation by itself after surgery and confirmed BCR. Their criteria for BCR is that at least one reading at or above 0.2 with a follow up in three months with a subsequent increase. There is also another leg of this same trial that includes radiation to the remaining lymph nodes.

Discuss with your oncologist on what will be the best protocol for you.
Posted 2/11/2011 2:03 PM (GMT 0)
Post surgery, my uro's view was that anything that is <0.1 is okay and anything that is more than 0.2 is not and requires further treatment; or put another way it did not really matter to him how fast the PSA was rising once it had risen.

My PSA in going up from 0.1 to 0.4 in three and a half months thus had a very high doubling time, which had it carried on at that rate would have given me bad numbers in a very short space of time (ie quadrupling every four months you go 0.1, 0.4, 1.6, 6.4, 25.6, 102.4, 400, 1600, and get to 6400 after just 3 years!)

The Math is more complex of course, and there is an almost theoretical as well as a real side to it.

But if your actual PSA numbers are say, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, etc every 3 months, then, while the doubling time between the first two is high, it gradually reduces (ie it takes only three months to double from 0.01 to 0.02, but takes a year to double from 0.04 to 0.08, and two years to double from 0.08 to 0.16 etc.)

So unless you, like me, get a sudden jump that clearly shows something is amiss, then you actually need a lot of test results to have mathematically useful numbers from which to calculate anything.

Alf
Posted 2/11/2011 7:56 PM (GMT 0)
The PCRI and the Yana websites have psa doubling time calculators.
JT
Posted 2/11/2011 8:08 PM (GMT 0)
Hey Goodlife,

Galileo hit it right on the head. Mathematically you cannot calculate doubling time from 0. You need at least 2 positive numbers spaced any distance apart.

There are calculators for it but I made an excel spread sheet that does it for you.
You enter the dates in one column is the date, and the PSAs in the next. The program calculates the doubling time from the previous value and puts it in the third column. Easy (if you have Excel.)
I'll send it to you if you want.

(I can also include my pee pad data if you want a plot of it for your refrigerator.)

Jeff
Posted 2/12/2011 3:59 AM (GMT 0)
Jeff,

Yes please send it to me.

Every doctor I have talked to this week has said, well, you know with a Gleason 9, we really don't know how to advise you because we really can't predict how the Gleason 9 will react. Basically, they all advise to throw the sink at it, for liability reasons and because they honestly don't know.

At this point, I am viewing a return of even low levels of Psa as a re-occurrence. I will monitor Psa for the next 3 months to get better handle on rate. I am not concerned with rate per se, I am just trying to predict radiation success odds.

Hope you continue to do well. Will be interested to see how increased activity will affect the leakage.

Baton Rouge, herecwe come !
Posted 11/17/2012 7:13 AM (GMT 0)
Hello
My dad was diagnosed with pc 4 yrs ago when he was 71. Something like 90% of the prostate was cancerous with about 11 out of 12 cores positive.  Gleason 9, psa 17, but contained after robotic surgery at the hands of Tony Costello in Melbourne. His psa has been in the undetecatble range for almost 4 yrs until yesterday...now .33. 6 months ago it was .09 and 6 months before that it had risen from .04 to .05. I am terrified...does the jump from .09 to .33 constitute a 3 month doubling time? Does it follow that a recurrence would be just as aggresive? Any thoughts would be much appreciated
Posted 11/17/2012 1:20 PM (GMT 0)
Hello

Welcome to HW. Sorry to hear about your Dad. I am certainly no doctor, but based on my experience, I would assume your Dad is experiencing a return of his PC.

You have some immediate choices to make. I would assume most doctors would commence Hormone Therapy therapy fairly quickly. Whether or not they recommend radiation will be a question. I would say based on his fairly rapid increase in PSA, there will be a debate on the effectiveness of radiation at this time.

Good luck and keep us informed on how your Dad is progressing.
Posted 11/18/2012 12:01 AM (GMT 0)
I build a little excel spreadsheet calculate the doubling time. This was a very useful exercise because you can see how much a change in a single reading can dramatically change the doubling time. The doubling time calculation is very volatile if you only have 3-4 data points in it. It gets more stable the more points you have. If you are thinking of pulling the trigger (or not) based on whether your PSADT is slightly above or below 12 months, I encourage you to do some testing to see just how readily the number can change.

If people are interested I can send a copy of the spreadsheet.

It's very simple and easy:
First, set up a table where each row is one test result and there are three columns:
In Column A: put the date of the test
Column B: the test result
Column C: the log of the test result: the actual formula is simply =log(B4) or whatever cell has the test result.

Then use the function that calculates the slope of the regression line for the log of the PSA. Don't worry if you don't understand what a slope is or what a regression line is, just paste the formulas and it will work. For example:
=SLOPE(C4:C12,A4:A12)
where c4:c12 holds the log of the PSA, and A4:A12 holds the date of the test. Change these cells to fit the actual locations of your data. This will give a very low number like .0006621 which actually corresponds to the rate of change per DAY.

Once you have this number you calculate the doubling time in days:
=LOG(2)/C13 where c13 holds the slope per day.

Once you have the doubling time in days you calculate the doubling time in months:
=C15/365*12 where c15 has the doubling time in days.

i think I have this right, but if any of you quant jocks out there spot an error, please let me know.

In addition, there are some articles that indicate that PSADT's calculated at low levels off ultrasensitive test results are pretty unreliable.

Post Edited (proscapt) : 11/17/2012 5:20:07 PM (GMT-7)

Posted 11/18/2012 12:16 AM (GMT 0)
Another thing to be considered is trying to understand your own doubling time and when to trigger SRT, is that nearly all the published research on doubling time and SRT was done before the widespread use of ultrasensitive PSA tests. PSADT calculated based on the old tests is much more stable (and usually slower) than PSADT calculated at very low levels using ultrasensitive tests. See this abstract below, by Peter Carrol's esteemed team at UCSF. The conclusion is extremely important for those contemplated salvage RT with low PSA's.

J Urol. 2011 Dec;186(6):2228-32. Epub 2011 Oct 19.
Poor agreement of prostate specific antigen doubling times calculated using ultrasensitive versus standard prostate specific antigen values: important impact on risk assessment.
Reese AC, Fradet V, Whitson JM, Davis CB, Carroll PR.
Source
Department of Urology, UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California 94115, USA.
Abstract

PURPOSE:
In men with biochemical recurrence after radical prostatectomy, a rapid prostate specific antigen doubling time is associated with adverse outcomes, and is often used to guide the type and timing of salvage therapy. It is unknown whether prostate specific antigen doubling time calculated in the ultrasensitive range (prostate specific antigen less than 0.2 ng/ml) accurately reflects measures performed in the traditional range (prostate specific antigen greater than 0.2 ng/ml).

MATERIALS AND METHODS:
We studied 394 men in a national disease registry of men with prostate cancer (CaPSURE™) who underwent radical prostatectomy, experienced biochemical failure, and had prostate specific antigen doubling time assessed using ultrasensitive and traditional prostate specific antigen values. Agreement between these measurements was assessed using Cohen's kappa score.

RESULTS:
Median ultrasensitive prostate specific antigen doubling time was 11.9 months (IQR 6-29) and median traditional prostate specific antigen doubling time was 240 months (IQR 18-240). Agreement between ultrasensitive and traditional prostate specific antigen doubling time was poor, with a weighted Cohen's kappa score of 0.04 (95% CI -0.02-0.10). Using a dichotomous prostate specific antigen doubling time cutoff of 9 months, there was a statistically significant difference between ultrasensitive and standard prostate specific antigen doubling time (exact McNemar p <0.01). Ultrasensitive prostate specific antigen doubling time was more or less rapid than traditional prostate specific antigen doubling time by more than 15 months in 244 (62%) and 35 (9%) patients, respectively.

CONCLUSIONS:
Agreement between prostate specific antigen doubling time calculated using ultrasensitive vs traditional prostate specific antigen values is poor. Ultrasensitive prostate specific antigen doubling time is often significantly more rapid than traditional prostate specific antigen doubling time, potentially overestimating the risk of clinical recurrence. Until the significance of ultrasensitive prostate specific antigen doubling time is better characterized, the decision to proceed with salvage therapy should not be based on prostate specific antigen doubling time calculated using ultrasensitive prostate specific antigen values.
Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Post Edited (proscapt) : 11/17/2012 5:23:13 PM (GMT-7)

Posted 11/18/2012 12:22 AM (GMT 0)
Goodlife,
Calculating doubling time on ultrasensitive psas, especially those of very low value would be very innaccurate as there are just too many variables. Lab differences and biological factors will affect psa to some extent, especially at the low numbers. Psa will also vary as to the time of day it is taken, so if you are not getting your blood drawn at the exact same time of the day you are introducing another variable.
Posted 11/18/2012 2:03 AM (GMT 0)
John T

I do understand what you are saying. Can't really find much specific info on it. That is why I have begun to look at trends.

I in fact do have PSA drawn at the same time each time. For 18 months my PSA held at <.01. Then it slowly over the next 18 rose to .06. I was more concerned with the trend than the actual number. The trend indicated BCR, so I proceeded to plan B.

Scared Daughter's father went from .09 to .33. Don't know how to calculate actual doubling time, but there is no doubt the trend indicates BCR.

Goodlife
Posted 11/18/2012 8:22 AM (GMT 0)
Goodlife, here's a formula you can use for calculating PSADT assuming you have two different psa results a certain number of months apart.

PSA1 = first value
PSA2 = second value
M = number of months between them

Then PSADT = .301 / (log((PSA2/PSA1)^(1/M))

So with scared daughter's data PSA1=.09 PSA2 = .33 M=6 Then PSADT = 3.2 months.
Posted 11/18/2012 8:57 PM (GMT 0)
My uro (and Rad doc) keep my notes on computer as well as on paper and they also keep a record of my PSA on a graph. This visual record makes it really easy to follow the changes and the speed of the changes, and is easy to follow than many of the mathematical calculations.

If you plot your PSA numbers on a graphic with time along the bottom(x) and PSA up the side (y) then you can think of your PSA doubling time in terms of how steep the slope of the line is or more importantly watch out for if the slope is getting steeper, shallower or staying constant.

At present I guess you could say my PSA is flat lining along the x axis!

Alf
Posted 1/27/2013 12:23 PM (GMT 0)
Hello

I must give a belated thank you to those who kindly replied to my post a couple of months ago. Im afraid I have only now come back to this thread by accident and recalled my post blush I guess thats what stress will do to you.

My Dads urologist was not a bit worried about his psa numbers...in fact he said he would like him to come for a chat, that there was no hurry and they scheduled an appointment for February - some 10 weeks later. That is now a week away and dad is going for another psa test in a couple of days. We are all really concerned as to what this rise will be. I have found a lot of evidence now that U/S psa test doubling times do not correlate well with eventual doubling times at higher levels so that is a source of some comfort now. Dad also had an appointment with a local radiologist who was keen to do radiation soon. So dad will speak with his urologist first and then ask for the best radiologist.

Does anyone know how to go about finding an excellent radiologist? And on another question...does anyone know much about Snuffy Myers? I have read most of his book on hormone therapy and diet and watched many of his online videos...I am very impressed by him.

Thank you again for your input.
Posted 1/27/2013 1:25 PM (GMT 0)
Scareddaughter

I had my radiation treatment at Sloan Kettering.

The entire staff is extremely professional and caring, plus they have the latest technology.

After my prostate was removed, my urologist didn't show much concern about my slowly advancing PSA. I went to Sloan Kettering and they did some internal imaging that uncovered a reoccurrence.

If they don't have an office in your area, look for another group that has the support staff and technology

LRX
Posted 1/28/2013 8:10 AM (GMT 0)
I read all of the posts here and I'm still rather confused. However, I realize that my husband has reason for concern.

He had a radical prostatectomy in November, 2010. His PSA went from about 30, prior to surgery, to 1.12 afterwards, which increased to 2.19 in about 6 weeks. Thus, the surgery failed. Post-op pathology report indicated Gleason 3+4, extracapsular extension, positive margin and seminal vesicle invasion.

In February, 2011, he started triple blockade androgen deprivation therapy. Radiation was not recommended to him due to a history of ulcerative colitis and belief that his cancer was already systemic.

His nadir was <.02 and he went into his "off cycle" in February, 2012. His PSA remained undetectable at <.02 for 11 months. However, at last check, his PSA was .05. That is a big jump from <.02! I wonder if this is an indication of a very fast doubling time, just like his post-surgery result.

I'm not in a state of panic over this yet. I'm just going to wait to see what his following PSA results will be...and that does make me nervous. Sometimes I wonder if his Gleason was analyzed properly. It was assessed as 3+4 both before and after surgery.

My husband is a patient of Dr. Myers and he's taking several supplements. He's also doubled his Avodart to try to lower his DHT, but it isn't doing what it's supposed to...Not sure what to do about that.

I look forward to any input on that <.02 to .05 increase in one month. He gets his PSA checked monthly.

Rhonda
Posted 1/28/2013 12:15 PM (GMT 0)
Online PSA doubling time calculator. http://www.doubling-time.com/compute-PSA-doubling-time.php

Can't vouch for it's accuracy.

...Jerry
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