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 guide treatment decisions.

2. How Does the Calculator Work?

The calculator uses the PSA doubling time formula:

Where:

• \( DT \) — Doubling time (months)
• \( T \) — Time interval between measurements (months)
• \( PSAi \) — Initial PSA level (ng/mL)
• \( PSAf \) — Final PSA level (ng/mL)
• \( \ln \) — Natural logarithm

Explanation: The formula calculates how quickly PSA levels are rising, with shorter doubling times indicating more aggressive disease.

3. Clinical Importance

Details: PSADT is used to:

• Monitor patients on active surveillance
• Assess risk of prostate cancer progression
• Guide decisions about treatment initiation
• Evaluate treatment response after therapy

4. Using the Calculator

Tips:

• Enter PSA values in ng/mL
• Time interval should be in months
• PSA values must be from the same laboratory when possible
• For accurate results, use PSA values measured at least 3 months apart

5. Frequently Asked Questions (FAQ)

Q1: What is a concerning PSA doubling time?
A: Generally, PSADT <12 months is concerning for aggressive disease, while >12 months suggests less aggressive cancer.

Q2: How many PSA values are needed for accurate calculation?
A: While two values can calculate PSADT, more measurements over time provide more reliable trends.

Q3: Does PSADT apply to all prostate cancer patients?
A: It's most useful for monitoring patients with biochemical recurrence or on active surveillance.

Q4: Can PSADT be used during treatment?
A: Yes, it can help assess treatment response, though interpretation differs from untreated cases.

Q5: What factors can affect PSA doubling time?
A: Factors include prostate manipulation (biopsy, DRE), infections (prostatitis), and certain medications.