1. What is PSA Doubling Time?

PSA doubling time (PSADT) is the time it takes for the prostate-specific antigen (PSA) level to double in value. It's an important prognostic marker in prostate cancer management, helping assess disease aggressiveness and progression.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( DT \) — PSA doubling time (months)
• \( t \) — Time between PSA measurements (months)
• \( PSA_1 \) — Initial PSA value (ng/mL)
• \( PSA_2 \) — Current PSA value (ng/mL)
• \( \ln \) — Natural logarithm

Explanation: The formula calculates the time required for PSA to double based on the observed rate of change between two measurements.

3. Importance of PSA Doubling Time

Details: PSADT helps in prostate cancer risk stratification, treatment decisions, and monitoring. Shorter doubling times (<3 months) may indicate more aggressive disease.

4. Using the Calculator

Tips: Enter both PSA values in ng/mL and the time between tests in months. Ensure PSA values are from the same laboratory for consistency.

5. Frequently Asked Questions (FAQ)

Q1: What is a clinically significant PSADT?
A: Generally, <3 months is concerning, 3-12 months is intermediate, and >12 months is favorable.

Q2: How many PSA values are needed for accurate calculation?
A: While two points can estimate DT, more measurements over time provide greater accuracy.

Q3: Does PSADT apply to all prostate cancer patients?
A: It's most useful for monitoring after treatment (especially after radical prostatectomy) and in active surveillance.

Q4: What factors can affect PSADT accuracy?
A: PSA bounces after radiation, prostatitis, recent procedures, or medications can temporarily affect PSA levels.

Q5: How often should PSA be measured for DT calculation?
A: Typically every 3-6 months, but frequency depends on clinical context and baseline risk.