# PSA (prostate-specific antigen)

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

## TL;DR

A blood protein made by the prostate; raised levels prompt further tests, and falling levels show treatment is working.

## Summary

Screening test with proven mortality reduction (ERSPC ~20% at 16 years) but substantial overdiagnosis; now paired with MRI and risk-adapted intervals. In treated disease, PSA kinetics (doubling time, PSA50/PSA90 response, nadir) are the everyday response measure, though not a validated surrogate for survival in mCRPC.

## Fields

- Kind: Term
- Last checked: 2026-09-06

## Notes

- After treatment: NICE NG131 (1.3.47) says to check PSA no earlier than 6 weeks after radical treatment, at least every 6 months for the first 2 years and at least once a year after that, and (1.3.48) not to routinely offer a digital rectal examination while the PSA stays at baseline. NG131 (1.3.49) allows remote follow-up after at least 6 months for people with a stable PSA and no significant complications.
- A rise is not an emergency. NICE NG131 (1.3.55) says to take into account that biochemical relapse alone should not mean an immediate change in treatment, and (1.3.56) to estimate PSA doubling time from a minimum of 3 measurements over at least a 6-month period. NG131 (1.3.59) says not to routinely offer hormone therapy for biochemical relapse unless there is symptomatic local progression, proven metastases, or a PSA doubling time of less than 3 months.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Prostate-specific_antigen
- Wikipedia: https://en.wikipedia.org/wiki/Prostate-specific_antigen
- NICE NG131: prostate cancer, diagnosis and management: https://www.nice.org.uk/guidance/ng131/chapter/Recommendations
- Prostate Cancer UK: follow-up after treatment: https://prostatecanceruk.org/prostate-information-and-support/treatments/follow-up-after-treatment

## Connected records

- cancers: [Biochemical recurrence of prostate cancer](https://onco.cc/cancers/prostate-bcr/), [Ductal adenocarcinoma of the prostate](https://onco.cc/cancers/prostate-ductal-adenocarcinoma/), [Localised prostate cancer, high and very high risk](https://onco.cc/cancers/prostate-high-risk/), [Localised prostate cancer, very low and low risk](https://onco.cc/cancers/prostate-low-risk/), [Non-metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-nmcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- terms: [Biochemical recurrence (BCR)](https://onco.cc/terms/biochemical-recurrence/), [Cambridge Prognostic Group (CPG 1 to 5)](https://onco.cc/terms/cambridge-prognostic-group/), [Intermittent androgen deprivation (IAD)](https://onco.cc/terms/intermittent-androgen-deprivation/), [Lead time, and lead-time bias](https://onco.cc/terms/lead-time-bias/), [Neuroendocrine differentiation in prostate cancer](https://onco.cc/terms/neuroendocrine-differentiation/), [Number needed to screen (and number needed to diagnose)](https://onco.cc/terms/number-needed-to-screen/), [Overdiagnosis](https://onco.cc/terms/overdiagnosis/), [PI-RADS (Prostate Imaging Reporting and Data System)](https://onco.cc/terms/pi-rads/), [Polygenic risk score (PRS)](https://onco.cc/terms/polygenic-risk-score/), [PSA density](https://onco.cc/terms/psa-density/), [PSA kinetics: PSA doubling time and PSA density](https://onco.cc/terms/psa-kinetics/), [PSA50 / PSA90 response](https://onco.cc/terms/psa50/), [Radiographic progression-free survival (rPFS)](https://onco.cc/terms/radiographic-progression-free-survival/), [Template mapping biopsy (transperineal template prostate mapping)](https://onco.cc/terms/template-mapping-biopsy/), [Watchful waiting, and how it differs from active surveillance](https://onco.cc/terms/watchful-waiting/)
- key papers: [Abiraterone in metastatic prostate cancer without previous chemotherapy](https://onco.cc/key-papers/paper-abiraterone-acetate-prostate-n-engl-j-med-2013/), [Accuracy of gallium-68 PSMA-11 PET in localising recurrent prostate cancer: a prospective single-arm clinical trial](https://onco.cc/key-papers/paper-fendler-psma-pet-biochemical-recurrence-jama-oncol-2019/), [AFFIRM: increased survival with enzalutamide in prostate cancer after chemotherapy](https://onco.cc/key-papers/paper-scher-affirm-enzalutamide-nejm-2012/), [AR-V7 and resistance to enzalutamide and abiraterone in prostate cancer](https://onco.cc/key-papers/paper-antonarakis-ar-v7-resistance-nejm-2014/), [Detection of individual prostate cancer foci via multiparametric magnetic resonance imaging](https://onco.cc/key-papers/paper-johnson-mpmri-individual-foci-eur-urol-2019/), [ERSPC: screening and prostate cancer mortality in a randomised European study](https://onco.cc/key-papers/paper-schroder-erspc-screening-mortality-nejm-2009/), [Lead time and overdiagnosis in prostate-specific antigen screening: importance of methods and context](https://onco.cc/key-papers/paper-draisma-lead-time-overdiagnosis-psa-jnci-2009/), [Measurement of prostate-specific antigen in serum as a screening test for prostate cancer](https://onco.cc/key-papers/paper-catalona-psa-screening-test-nejm-1991/), [Overdiagnosis and overtreatment of prostate cancer](https://onco.cc/key-papers/paper-loeb-overdiagnosis-overtreatment-prostate-eur-urol-2014/), [Phase 1 trial of abiraterone acetate confirms that castration-resistant prostate cancer commonly remains hormone driven](https://onco.cc/key-papers/paper-attard-abiraterone-phase-1-cyp17-jco-2008/), [PIVOT: follow-up of prostatectomy versus observation for early prostate cancer](https://onco.cc/key-papers/paper-wilt-pivot-prostatectomy-observation-nejm-2017/), [PLCO: mortality results from a randomised prostate cancer screening trial](https://onco.cc/key-papers/paper-andriole-plco-prostate-screening-nejm-2009/), [PREVAIL: enzalutamide in metastatic prostate cancer before chemotherapy](https://onco.cc/key-papers/paper-beer-prevail-enzalutamide-nejm-2014/), [PROMIS: diagnostic accuracy of multiparametric MRI and TRUS biopsy in prostate cancer](https://onco.cc/key-papers/paper-ahmed-promis-multiparametric-mri-lancet-2017/), [Prostate cancer diagnosis and treatment after the introduction of prostate-specific antigen screening, 1986 to 2005](https://onco.cc/key-papers/paper-welch-albertsen-psa-era-diagnosis-treatment-jnci-2009/), [Prostate-specific antigen as a serum marker for adenocarcinoma of the prostate](https://onco.cc/key-papers/paper-stamey-psa-serum-marker-nejm-1987/), [RESTORE: bipolar androgen therapy after progression on enzalutamide in metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-teply-restore-bipolar-androgen-therapy-lancet-oncol-2018/), [SWOG 9346: intermittent versus continuous androgen deprivation in metastatic prostate cancer](https://onco.cc/key-papers/paper-hussain-swog-9346-intermittent-androgen-deprivation-nejm-2013/), [SWOG 9916: docetaxel and estramustine compared with mitoxantrone and prednisone for advanced refractory prostate cancer](https://onco.cc/key-papers/paper-petrylak-swog-9916-docetaxel-estramustine-nejm-2004/), [TAX 327: docetaxel plus prednisone or mitoxantrone plus prednisone for advanced prostate cancer](https://onco.cc/key-papers/paper-tannock-tax-327-docetaxel-prednisone-nejm-2004/), [TRANSFORMER: bipolar androgen therapy versus enzalutamide in asymptomatic metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-denmeade-transformer-bipolar-androgen-therapy-jco-2021/), [TRITON2: rucaparib in men with metastatic castration-resistant prostate cancer harbouring a BRCA1 or BRCA2 alteration](https://onco.cc/key-papers/paper-abida-triton2-rucaparib-brca-jco-2020/), [USPSTF 2012: screening for prostate cancer, recommendation statement (grade D)](https://onco.cc/key-papers/paper-moyer-uspstf-prostate-screening-ann-intern-med-2012/), [USPSTF 2018: screening for prostate cancer, recommendation statement (grade C at 55 to 69, grade D at 70 and over)](https://onco.cc/key-papers/paper-uspstf-prostate-screening-jama-2018/)
- ideas: [Judge a prostate screening programme on metastatic presentation, not on incidence or mortality](https://onco.cc/ideas/idea-prostate-metastatic-presentation-as-the-screening-endpoint/), [Take high-dose testosterone to phase 3, with progression-free survival through the second line as the primary endpoint](https://onco.cc/ideas/idea-prostate-bipolar-androgen-therapy-phase-3-on-pfs2/)
- drugs: [Prolaris](https://onco.cc/drugs/prolaris/), [PROSTVAC](https://onco.cc/drugs/prostvac/)
- trials: [ERSPC (European Randomized Study of Screening for Prostate Cancer)](https://onco.cc/trials/erspc/), [GÖTEBORG-2 (MRI-based prostate cancer screening)](https://onco.cc/trials/goteborg-2/), [ORIOLE](https://onco.cc/trials/oriole/), [PIVOT (Prostate Cancer Intervention Versus Observation Trial)](https://onco.cc/trials/pivot/), [PLCO, prostate component (Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial)](https://onco.cc/trials/plco-prostate/), [PROMIS](https://onco.cc/trials/promis/), [PROSPECT](https://onco.cc/trials/prospect-prostvac/), [RTOG 0415](https://onco.cc/trials/rtog-0415/), [SWOG 9346 (intermittent androgen deprivation)](https://onco.cc/trials/swog-9346/), [TRANSFORM](https://onco.cc/trials/transform-prostate/)
- institutions: [Prostate Cancer UK](https://onco.cc/institutions/prostate-cancer-uk/)
- biomarkers: [Treatment-emergent neuroendocrine transformation (recognising it)](https://onco.cc/biomarkers/nepc-transformation/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/)
- collections: [Prostate Cancer Foundation (PCF)](https://onco.cc/collections/prostate-cancer-foundation/)
- technologies: [PSA and MRI-first prostate cancer screening](https://onco.cc/technologies/prostate-screening-psa-mri/), [Serum tumour markers: proper use and misuse](https://onco.cc/technologies/serum-tumour-markers/)

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