# Judge a prostate screening programme on metastatic presentation, not on incidence or mortality

Source: https://onco.cc/ideas/idea-prostate-metastatic-presentation-as-the-screening-endpoint/  
OnCo record `idea-prostate-metastatic-presentation-as-the-screening-endpoint` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Screening trials are judged on deaths, which take fifteen years to count, and on cancers found, which is the wrong direction. Preventing a man from turning up with cancer already in his bones happens three times as often as preventing a death, arrives years earlier, and is the outcome he cares about.

## Summary

The 2018 United States task force statement quantifies both: screening men aged 55 to 69 may prevent approximately 1.3 deaths from prostate cancer and approximately 3 cases of metastatic prostate cancer per 1,000 men screened over about 13 years. The metastatic endpoint is more than twice as frequent, and it precedes death by years, so a trial powered on it reads out sooner and smaller. It is also the endpoint that separates the benefit of screening from its harm: overdiagnosis inflates incidence, so incidence is actively misleading, and mortality is confounded by improvements in treatment over the decades a screening trial runs.

Draisma showed that mean lead time is 5.4 to 6.9 years, which is the interval within which a metastatic presentation can be prevented and after which it cannot. The proposal is to adopt the rate of de novo metastatic presentation in the invited population as the primary outcome of any new prostate screening programme or trial, reported per 1,000 invited rather than per 1,000 screened, with prostate cancer mortality as a long-term secondary and incidence reported only as a harm. It is a change in what is measured rather than in what is done, which makes it cheap, and it would let the magnetic resonance imaging-first pathways such as Goteborg-2 be evaluated on a timescale on which policy can actually act.

UK and NHS specifics (the National Screening Committee position, NICE technology appraisals and their recommendation numbers, Cancer Drugs Fund status, magnetic resonance imaging and radiotherapy capacity, National Prostate Cancer Audit indicators and trial access) belong on the UK and NHS page for prostate cancer and are not restated here.

## Fields

- Kind: Idea
- Last checked: 2026-09-25
- Also known as: metastasis-free survival screening endpoint prostate; metastatic presentation as screening outcome
- Tags: prostate-evidence
- Hypothesis: De novo metastatic presentation in the invited population is a valid and substantially more efficient primary endpoint for prostate cancer screening than prostate cancer mortality: it occurs roughly three times as often, precedes mortality by years, is not inflated by overdiagnosis, and would allow a screening pathway to be evaluated in about half the follow-up time with a comparable or smaller sample.
- Rationale: Incidence is the wrong direction of merit in a disease where a quarter to two thirds of screen-detected cancers may be overdiagnosed, depending on definition and population; a programme that finds more cancers may be doing harm. Mortality is right but slow and confounded: over the 13 to 20 years a screening trial runs, treatment for metastatic disease has repeatedly improved, which dilutes the measured screening effect in a way that has nothing to do with the screening. Metastatic presentation is neither inflated by overdiagnosis nor rescued by better systemic therapy, it is the event that ends curative intent, and the task force's own numbers say it is about three times as common as a prevented death. Reporting per 1,000 invited rather than per 1,000 screened additionally makes uptake part of the measured outcome rather than an excuse for it.
- Proposed test: Two steps. First, a validation analysis in the existing randomised datasets: re-analyse ERSPC and the Cluster Randomised Trial of PSA Testing with de novo metastatic presentation as the endpoint and measure how many years earlier the observed effect reaches significance, and how closely the metastatic and mortality effects agree. Second, if the surrogacy holds, register metastatic presentation per 1,000 invited as the pre-specified primary outcome of the next generation of screening evaluations, including the magnetic resonance imaging-first pathways, with mortality retained as a long-term secondary. Step one is a secondary analysis of existing data and could be done in a year.
- Maturity: speculative
- Actor: policy

## Connected records

- ideas: [MRI-first prostate screening with genetic pre-selection](https://onco.cc/ideas/idea-prev-mri-first-prostate-screening-prs/), [Test whether calling Gleason 6 'not cancer' changes what men choose](https://onco.cc/ideas/idea-prev-gleason6-terminology-rct/), [Use a polygenic risk score to set when screening starts](https://onco.cc/ideas/idea-prev-prs-screening-start-age/)
- roadmaps: [Early detection roadmap: organ screening → blood tests for many cancers](https://onco.cc/roadmaps/early-detection-roadmap/), [Prostate cancer roadmap: from Huggins and the discovery that a cancer can depend on a hormone, through the PSA epidemic and what it cost, the androgen receptor drugs, the DNA repair subset and PSMA, to a 2032 registry watch](https://onco.cc/roadmaps/prostate-roadmap/)
- cancers: [Localised prostate cancer, high and very high risk](https://onco.cc/cancers/prostate-high-risk/), [Localised prostate cancer, intermediate risk](https://onco.cc/cancers/prostate-intermediate-risk/), [Localised prostate cancer, very low and low risk](https://onco.cc/cancers/prostate-low-risk/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- fronts: [Early Detection & Screening](https://onco.cc/fronts/early-detection/), [Prevention & Risk](https://onco.cc/fronts/prevention/)
- technologies: [MRI](https://onco.cc/technologies/mri/), [PSA and MRI-first prostate cancer screening](https://onco.cc/technologies/prostate-screening-psa-mri/)
- terms: [Lead time, and lead-time bias](https://onco.cc/terms/lead-time-bias/), [Metastasis-free survival (MFS)](https://onco.cc/terms/metastasis-free-survival/), [Number needed to screen (and number needed to diagnose)](https://onco.cc/terms/number-needed-to-screen/), [Overdiagnosis](https://onco.cc/terms/overdiagnosis/), [Overtreatment](https://onco.cc/terms/overtreatment/), [PSA (prostate-specific antigen)](https://onco.cc/terms/psa/), [Screening](https://onco.cc/terms/screening/)
- bottlenecks: [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/), [Prevention we already have is not deployed](https://onco.cc/bottlenecks/b-prevention-adoption/), [The hardest cancers are found late](https://onco.cc/bottlenecks/b-early-detection/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/)
- key papers: [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/), [Overdiagnosis and overtreatment of prostate cancer](https://onco.cc/key-papers/paper-loeb-overdiagnosis-overtreatment-prostate-eur-urol-2014/), [Prostate Cancer Screening with PSA and MRI Followed by Targeted Biopsy Only](https://onco.cc/key-papers/paper-goteborg-2-n-engl-j-med-2022/), [Prostate-Specific Antigen Screening and 15-Year Prostate Cancer Mortality: A Secondary Analysis of the CAP Randomized Clinical Trial](https://onco.cc/key-papers/paper-martin-jama/), [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/)

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