Tumor volume?

I have been on AS for a little over two years and recently had my first 3T MRI with abdominal coil. It found a small lesion slightly less than one centimeter consistent with Gleason 6. I know a centimeter is less than half an inch, but as far as PCa goes would this still be considered low volume?


P.S.
Glad to read that you guys and gals that made it to the FL. GFMPH had a great time!

That's a small tumor.

It depends a lot on the location, type and aggressivenes. You show as a G6 so that is at the low end of the scale. Generally they may grow slowly, but usually don't spread. The size you have doesn't appear to be a problem unless it starts to cause physical problems similar to what prostate enlargement can. If you were a G9 or 10, I would say the cancer is becoming very significant at that size as we know the high grade PCa can do a lot of harm before it shows up on scans. As with most everything else, size is relative.

What does the doctor say?

jym62,

How do you know whether the small lesion identified by the MRI is cancer if it wasn't biopsied or even investigated with a multiparametric MRI?

It sounds like the Avodart is doing a great job at shrinking the GS6 tumors that were found on your earlier biopsy. I would be thrilled with your recent findings.

BTW, Epstein at JH considers "insignificant" to be low risk plus .5 ccs + .15 PSA density + <2/12 positive cores. If the largest dimension on yours is less than cm, that lesion is probably well under .5 cc.

- Allen

Let's get in the weeds. Pre-Avodart, assuming your prostate was about 35cc, it should have given off about 2.31 PSA (35x0.066) leaving 3.29 PSA from a G6 tumor. The tumor volume would be about .82 cc (3.29 PSA /4=0.82). Now the Avodart has obviously shrunk both your prostate and the tumor to much smaller sizes. For my calculation, if your prostate was actually smaller it would indicate the tumor was a bit larger and vice versa.

It looks to me that the Avodart is working and the AS can continue. To my knowledge no one has had real problems at your stage. According to the trials Reduce and Redeem, Dutasteride (Avodart) showed a reduction of PCa incidence. Importantly, both trials showed that by reducing PSA, subsequent increases in PSA were more reliably indicating PCA progression so that further biopsies and treatment plans could be considered.

If I were in your shoes I would seriously consider continuing AS and as long as PSA stayed in it's present range, delay further biopsies. Of course, I would only do this under the guidance of an urologist that can demonstrate he/she has numerous AS patients pursuing such a strategy. I certainly wouldn't be considering invasive treatment at this stage with this evidence.

The only thing I know about calculating the volume is the factors that Dr Stephen Sturm published. My uro walked me through them when he diagnosed me and mapped the prostate involvement based on the biopsy. I assume they remain constant regardless of the use of Avodart. Sturm indicates that a benign prostate gives off about 0.066 PSA per cc of volume. Cancer generally gives off much more than that but reduces as the G scale increases.

Before Avodart your prostste volume was 72cc x 0.066 = 5.08 PSA. So 0.50 or so PSA was coming from the cancer. At a factor of 4 for G6 this would indicate about 0.125cc of cancer. Post Avodart your prostate is 44.7cc x 0.066 = 2.95 PSA. Comparing this estimate to your current PSA indicates you have very little G6 volume. As TallAllen estimated less than 0.5 cc. By comparison a pea is about 0.2 cc.

Of course all this is estimated, but based on your PSA, biopsy, MRI, etc. it appears at present your volume is very small and your risk is low. That may all change in the future, but I still think your are in a good place and that continued AS may serve you very well. I certainly would trade my dx and treatment for your situation.

Hey,
Thanks again guys!

jym,

Go to www.lef.org. Then find the pdf LE-PAGEID-119464.pdf entitled "Life Extension, Introduction to Dr. Strum's Prostate Cancer Update". It is a 73 page work by Strum that is well worth the read. On page 28 Table 11 "PSA Leak Versus Weighted Gleason Score" is what you are looking for.