# PSA kinetics: PSA doubling time and PSA density

Source: https://nuclide.cc/terms/psa-kinetics/  
Nuclide record `psa-kinetics` (Term). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

How fast PSA is rising matters more than its level: a doubling time under ten months after surgery or radiotherapy, or under nine months in castration-resistant disease, marks the men whose cancer is moving quickly and who benefit from earlier hormone therapy or a PSMA scan, while PSA density (PSA divided by prostate volume) helps decide who needs a biopsy at all.

## Summary

What is measured: the rate of change of prostate-specific antigen and its concentration relative to gland size. How: doubling time is calculated by log-linear regression from at least three values over at least three months; density is PSA (ng/mL) divided by prostate volume (mL) on MRI or ultrasound, with 0.15 (0.10 with MRI) the usual threshold. Confounders: 5-alpha-reductase inhibitors halve PSA, prostatitis raises it. What a result changes: after radical prostatectomy a PSA of 0.2 ng/mL or more defines biochemical recurrence, and the EAU splits it into low and high risk by a doubling time of a year or less or a Gleason grade group of 4 or 5, which sets the urgency of salvage radiotherapy and whether hormone therapy is added; PSMA PET is positive in most men above 0.5 ng/mL; in non-metastatic castration-resistant disease a doubling time of ten months or less was the entry criterion for SPARTAN (apalutamide), PROSPER (enzalutamide) and ARAMIS (darolutamide), which lengthened metastasis-free and overall survival; a density above 0.15 with a PI-RADS 3 lesion tips towards biopsy, and density is an entry criterion for active surveillance (PRIAS 0.2 or less); in metastatic castration-resistant disease a 50 percent PSA fall (PSA50) is a trial endpoint, and a PSA under 0.2 at seven months of hormone therapy predicts long survival. Where it matters: biochemical recurrence, low-risk, non-metastatic castration-resistant and metastatic castration-resistant prostate cancer.

## Fields

- Kind: Term
- Last checked: 2026-09-17
- Also known as: PSA doubling time; PSADT; PSA velocity; PSA density; PSAD; PSA kinetics; PSA rise; rising PSA; biochemical recurrence PSA threshold; PSA nadir; PSA response; PSA50; PSA90; PSA progression

## Connected records

- technologies: [PSMA PET](https://nuclide.cc/technologies/psma-pet/)
- drugs: [Enzalutamide](https://nuclide.cc/drugs/enzalutamide/)
- indications: [Biochemical recurrence of prostate cancer](https://nuclide.cc/indications/prostate-bcr/), [Metastatic castration-resistant prostate cancer](https://nuclide.cc/indications/prostate-mcrpc/), [Non-metastatic castration-resistant prostate cancer](https://nuclide.cc/indications/prostate-nmcrpc/)
- terms: [Flare phenomenon](https://nuclide.cc/terms/flare-phenomenon/)

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