1. What is Prostate Doubling Time?

Prostate doubling time (PSADT) is the time it takes for prostate-specific antigen (PSA) levels to double. 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:

• \( td \) — Prostate doubling time (months)
• \( PSA1 \) — Initial PSA value (ng/mL)
• \( PSA2 \) — Current PSA value (ng/mL)
• \( t1 \) — Time of initial PSA measurement (months)
• \( t2 \) — Time of current PSA measurement (months)
• \( \ln \) — Natural logarithm

Explanation: The formula calculates the exponential growth rate of PSA and determines how long it would take to double at that rate.

3. Clinical Importance

Details: PSADT is used to monitor prostate cancer progression, guide treatment decisions, and predict outcomes. Shorter doubling times (<3 months) suggest more aggressive disease.

4. Using the Calculator

Tips: Enter PSA values in ng/mL and time points in months. Ensure PSA values are from the same assay and patient conditions were similar (no recent procedures affecting PSA).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal PSADT?
A: There's no "normal" PSADT, but in prostate cancer: >15 months is slow, 3-15 months is intermediate, and <3 months is fast-growing.

Q2: How many PSA points are needed?
A: While two points give an estimate, more measurements over time provide a more reliable trend.

Q3: Does PSADT correlate with prognosis?
A: Yes, shorter PSADT correlates with higher Gleason scores, advanced stage, and worse outcomes.

Q4: What affects PSADT accuracy?
A: PSA bounces, prostatitis, recent procedures, and different assay methods can affect results.

Q5: Can this be used during active treatment?
A: PSADT is most meaningful when measured during untreated disease or biochemical recurrence.