PSA Doubling Time (PSADT) Calculator
Calculates rate of PSA doubling in prostate cancer (correlates with survival).
- Use at least 3 PSA values obtained over an interval of at least 3 months, ideally from the same laboratory/assay, to improve the reliability of the doubling-time estimate.
- Exclude PSA values obtained shortly after a treatment change (e.g., initiation or discontinuation of androgen deprivation therapy [ADT]) that could confound the true kinetics of recurrence.
- Confirm castrate testosterone (<50 ng/dL) before using PSADT to guide treatment decisions in the castration-resistant setting; a rapidly rising PSA in a patient not confirmed to be castrate may reflect testosterone recovery rather than true castration resistance.
Advice
- Further management should be individualized based on age, comorbidities, life expectancy, patient preferences, and other relevant factors.
- Results should not be used in isolation but should be interpreted alongside Gleason Score, time to biochemical recurrence, and disease extent when counseling patients or selecting therapy.
Management
- With biochemical recurrence after radical prostatectomy or radiation therapy, a PSADT ≤9 months (with an absolute PSA rise above the nadir/threshold and castrate-sensitive, non-metastatic disease) meets the NCCN definition of high-risk biochemical recurrence; options include observation, ADT alone, or enzalutamide with or without leuprolide, based on the EMBARK trial.
- With non-metastatic castration-resistant prostate cancer (nmCRPC) and confirmed castrate testosterone, a PSADT ≤10 months identifies patients most likely to benefit from a second-generation antiandrogen (e.g., apalutamide, enzalutamide, darolutamide), based on the SPARTAN, PROSPER, and ARAMIS trials.
- Patients with longer PSADT and otherwise lower-risk features may reasonably continue observation with serial PSA monitoring, per NCCN guidance.
More detailed information can be found in the NCCN Guidelines.