Should PSA Super Dive Warrant Updated Imaging?

@brianjarvis And my question is always this: if the ‘healthy’ cells survive, how do we know that the damage incurred was such that it now made those cells anaplastic?
If salvage radiation comes with the caveat of secondary cancers, why wouldn’t it come from primary radiation as well inside the prostate?

@heavyphil The second question is easier…..let’s do that first.

Yes, it can happen inside the prostate; but that risk is low. Remember that healthy prostate cells have an inherent ability to repair DNA damage; cancerous prostate cells do not. (See attached graphic.) ADT (& sometimes ARPI) is given with radiation treatments to starve/weaken prostate cancer cells to suppress the DNA repair mechanisms (and this is why ADT is a very important component to kill prostate cancer cells).

Secondary cancers (whether from primary or salvage radiation) occurs when healthy cells are damaged by radiation, are unable to repair themselves, and then mutate into cells that grow rapidly and uncontrollably (which is what cancer is).

During radiation treatments, we want the cancer cells to die (as a result of DNA damage and not repair themselves), and we want as many healthy cells as possible to repair themselves…or die. Not mutate. And that’s (fortunately) what usually happens. Also, remember that these are ablative doses of radiation.

Secondary cancers sometimes occur when radiation overshoots the prostate and hits otherwise heathy nearby tissues and organs - rectum, bladder, intestines, etc. Those cells also have DNA repair mechanisms. As those cells are affected, that results in proctitis, cystitis, hematuria, dysuria, rectal bleeding, diarrhea/constipation, etc. If those cells can repair themselves, the problem goes away over time. If those cells cannot repair themselves, and don’t die, they can mutate and result in secondary cancers.

@heavyphil Regarding the first question —> If you recall that presentation by Dr. Rossi at the 2023 Mid-Year PCRI presentation: https://www.youtube.com/live/WTqPnSRYtW4

…at around timestamp 4:54:15 he’s asked a question (about re-radiation) where he responds, “…this gets to our unknowns; even though that normal tissue may not have been clinically damaged when you first treated it (with radiation), you may create some microscopic injury that may or may not be repaired. And we’re now just learning about how much of that is repaired as time goes by.”

They’re apparently still learning about that, what happens in the long term, and why.

@heavyphil
The Stanford study was covering a lot of men and found only a .5% increase In secondary cancers due to radiation.

In a study of about 145,000 men with prostate cancer, the team found that the rate of developing a later cancer is 0.5% higher for those who received radiation treatment than for those who did not. Among men who received radiation, 3% developed another cancer, while among those who were treated without radiation, 2.5% developed another cancer.
https://med.stanford.edu/news/all-news/2022/070/prostate-radiation-slightly-increases-the-risk-of-developing-ano.html

@brianjarvis yes, I would imagine so, Brian, and it’s almost impossible at this stage to know what percentage of cells are damaged and go on to be actually mutated. Prostate cells are like any other type of epithelial cell; they divide rapidly and often, and therefore are the most susceptible to the effects of ionizing radiation..
Thanks for the video!
Phil

@jeffmarc That is a great study! I knew the rate of secondary cancers was not high, but had NO idea it was THAT low….
My original thoughts were more prostate centric; SBRT has margins and many cells in those areas are really getting the full hit - not the scatter and weaker pass thru rays of the surrounding tissues. Thanks for the article!
Phil