My Prostate Cancer is stable but not shrinking — is treatment still working

Is Your Treatment Working If Cancer Is Stable But Not Shrinking?

This is an excellent and important question that many prostate cancer patients ask. The short answer is: yes, stability can absolutely represent meaningful benefit — but it depends on your specific situation and how your doctors are measuring response.

Understanding "Response" in Prostate Cancer

According to the CancerPatientLab webinars on prostate cancer treatment, doctors traditionally measure treatment success in three ways:

1. Remission (cancer shrinks significantly)
2. Stable disease (cancer stays the same size)
3. Progression (cancer grows)

As Dr. [removed] Antonarakis explains in his discussion of Bipolar Androgen Therapy, about one-third of patients achieve remission, about one-third achieve stable disease, and about one-third experience progression. This means stability is a common and valuable outcome.

Why Stability Matters

Here's the critical insight: Slowing or stopping cancer growth is a real therapeutic benefit, even without shrinkage.

Think of it this way: If your cancer was growing at a certain rate before treatment, and now it's staying flat, your treatment is working by changing the cancer's behavior. As Dr. [removed] Subudhi notes in the immunotherapy webinar, a patient can have "stable disease" where "he's not outright progressing" — and this represents a meaningful response that may warrant continued treatment.

The PSA Paradox

One important caveat: PSA (prostate-specific antigen) levels don't always tell the whole story. According to the webinars:

• Sometimes PSA will increase while scans show stable disease or even improvement
• Sometimes PSA decreases while scans temporarily worsen (this can happen in the first 2-3 months of certain treatments)
• PSA is "a rough marker" — scans and clinical symptoms are often more reliable

This is why your doctors should be looking at multiple measures, not just PSA numbers alone.

Questions to Ask Your Oncologist

Since your cancer is stable, these questions will help you understand if treatment is truly working for YOUR situation:

1. "Compared to my baseline (before treatment), is my cancer smaller, the same size, or growing?" This clarifies whether you have true stable disease.

2. "What was my PSA doubling time before treatment, and what is it now?" A slower doubling time indicates your treatment is slowing progression.

3. "Are we seeing this stability on imaging (scans), or just in PSA numbers?" This helps distinguish real response from misleading lab values.

4. "How long do you expect this stability to last, and what's our plan if the cancer starts growing again?" This helps you understand the trajectory and next steps.

5. "Should we continue this treatment, adjust the dose, or consider adding another therapy?" Different situations call for different approaches — some patients benefit from continuing stable regimens, while others may benefit from treatment intensification.

Important Context: Treatment Goals Vary

According to the webinars, treatment goals depend on your cancer stage:

• For metastatic hormone-sensitive prostate cancer: Treatment intensification (combinations of therapies) is now standard of care
• For castrate-resistant disease: Maintaining stability while preserving quality of life is often a realistic goal
• For low-volume disease: Stability may be an excellent outcome that allows you to avoid or delay more aggressive treatments

The Bottom Line

Stable disease is not treatment failure — it's a meaningful clinical benefit. Your cancer is not progressing, which means:

• You're likely living longer than you would without treatment
• You may have more time before needing to switch therapies
• Your quality of life may be better than with progressive disease

However, stability should be confirmed on imaging (not just PSA), and your care team should have a clear plan for monitoring and next steps.

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This information is for educational purposes only. Always consult your healthcare team for personalized medical advice and decisions.