Making Sense of PSA After Treatment: Persistence (Part 3)

If PSA does not go away after prostatectomy, this is called “PSA persistence,” and there are three things that could be causing it, says Weill Cornell Medicine urologist Jim C. Hu, M.D., M.P.H.

There could be some normal prostate tissue left behind.  “This was more common when we first started doing robotic prostatectomy,” instead of the open surgical procedure, says Hu, “but it still does happen.”

There could be some prostate cancer that has left the prostate, but is still in the local area, and can be treated with “salvage” radiation therapy.  Even if you had a PSMA-PET scan, and/or a bone scan or CT scan before treatment, this is a possibility, particularly if you had high-volume unfavorable risk cancer (Grade Group 3, or Gleason 4+3=7) or higher-grade cancer (Grade Group 4 or 5, or Gleason 4+4=8 or higher).  It could be that this cancer was too small to be seen on imaging, and now has gotten bigger.  “This can happen, even if the lymph node dissection during surgery showed no cancer,” says Hu. “There could be one area or several areas producing enough PSA to be above 0.2 ng/ml.”

Depending on the results of imaging – PSMA-PET, a bone scan, and/or CT scan – salvage radiation could cover just the prostate bed or the entire pelvis.  Or, it could just target highly specific areas, because:

There could be oligometastasis.  Here again, it’s possible that a few micrometastases – too small to be seen even by PSMA-PET – escaped the prostate before surgery, and now have gotten big enough to be seen.  If there are just a few isolated spots, this is called oligometastasis.  It’s not full-blown metastasis, and most important to know: “You can still go for a cure,” says Hu, “with targeted stereotactic radiation therapy to those areas, and a salvage lymph node dissection.”  There is a chance that further micrometastases will reveal themselves after this treatment, Hu says.  But University of Maryland radiation oncologist Phuoc Tran, M.D., Ph.D., who has pioneered research and treatment in prostate cancer oligometastasis, says those new spots can be “zapped,” as well – still with a chance of a cure.   He likens this approach to “whack-a-mole.”

What about androgen deprivation therapy (ADT) with radiation?  “There’s still shared decision-making,” Hu notes, where you and your doctor discuss the risks and benefits of a short-term course of ADT along with radiation therapy.  However, he advises that patients seriously consider it.  “The new guidelines say you should add ADT to salvage radiation if someone has high-risk features, such as positive surgical margins, cancer in the seminal vesicles, or Grade Group 4 or 5 cancer,” and this, in Hu’s opinion, is the smartest thing to do.  “There’s not a conclusive, randomized trial that says you absolutely should have it – but if you want to have the highest chance of cure, I think you should do ADT along with the radiation.  If I have prostate cancer and primary therapy has not worked, I don’t want to miss the window of curability again; I want to maximize my chance of cure with radiation therapy and temporary ADT.”