Undetectable. is it possible to know if this is due to ongoing ADT vs. cancer absence? How to think about this

Understanding Undetectable PSA on ADT

This is an excellent and important question. The short answer is: an undetectable PSA while on ADT doesn't definitively tell you whether cancer is completely gone or being suppressed by the hormone therapy. Let me explain why and how to think about this.

Why ADT Makes This Complicated

ADT (androgen deprivation therapy) works by starving prostate cancer cells of the hormones they need to grow and produce PSA. According to the NCCN Guidelines for Patients: Advanced-Stage Prostate Cancer, ADT is used to "slow cancer and delay or reduce symptoms."

The key issue: ADT suppresses PSA production, but it doesn't necessarily eliminate all cancer cells. So an undetectable PSA could mean:

• The cancer is in remission (controlled but possibly still present)
• The cancer has been eliminated
• There are cancer cells present but they're being held in check by the hormone therapy

How to Think About Your Situation

1. Consider your treatment history

• If you had surgery (radical prostatectomy) followed by ADT, an undetectable PSA is more reassuring—all PSA-producing tissue should have been removed surgically
• If you had radiation therapy followed by ADT, the picture is less clear because some prostate tissue may remain

2. Look at the bigger picture beyond PSA According to the NCCN Guidelines for Patients: Early-Stage Prostate Cancer, when evaluating PSA changes, doctors also consider:

• Imaging studies (CT, MRI, bone scans) to check for cancer in other areas
• PSA doubling time (how quickly PSA rises if it does recur)
• Your overall health and life expectancy

3. Understand what happens if PSA rises The NCCN Guidelines note that PSA recurrence—when PSA drops but then starts rising again—"may be signs that cancer hasn't fully gone away or that it may come back in other parts of the body."

Questions to Ask Your Oncologist

• How long have I been on ADT, and what's the plan for duration?
• Should I have imaging studies to confirm no cancer spread?
• What PSA level or rise would trigger a change in my treatment?
• What's my individual prognosis based on my specific cancer characteristics?

The bottom line: An undetectable PSA on ADT is a good sign that your cancer is being controlled, but it's not the same as knowing the cancer is gone. Your oncologist can help interpret what it means for your specific situation.