Population‐based randomized trial of screening for clinically significant prostate cancer ProScreen: pilot study

Key learning on the promise and limitations of MRI in prostate cancer screening

MRI retains its ability to reduce the harm of prostate biopsies by decreasing biopsy rates and the detection of indolent cancers in population-based screening studies aiming to find clinically significant prostate cancers. Limitations of low positive predictive values and high reader variability in diagnostic performance require optimisations in patient selection, imaging protocols, interpretation standards, diagnostic thresholds, and biopsy methods. Improvements in diagnostic accuracy could come about through emerging technologies like risk calculators and polygenic risk scores to select men for MRI. Furthermore, artificial intelligence and workflow optimisations focused on streamlining the diagnostic pathway, quality control, and assurance measures will improve MRI variability. CLINICAL RELEVANCE STATEMENT: MRI significantly reduces harm in prostate cancer screening, lowering unnecessary biopsies and minimizing the overdiagnosis of indolent cancers. MRI maintains the effective detection of high-grade cancers, thus improving the overall benefit-to-harm ratio in population-based screenings with or without using serum prostate-specific antigen (PSA) for patient selection. KEY POINTS: • The use of MRI enables the harm reduction benefits seen in individual early cancer detection to be extended to both risk-stratified and non-stratified prostate cancer screening populations. • MRI limitations include a low positive predictive value and imperfect reader variability, which require standardising interpretations, biopsy methods, and integration into a quality diagnostic pathway. • Current evidence is based on one-time point use of MRI in screening; MRI effectiveness in multiple rounds of screening is not well-documented.

Prostate Cancer Early Detection in the European Union and UK

BACKGROUND AND OBJECTIVE

While prostate cancer (PCa) incidence and mortality rates continue to rise, early detection of PCa remains highly controversial, and the research landscape is rapidly evolving. Existing systematic reviews (SRs) and meta-analyses (MAs) provide valuable insights, but often focus on single aspects of early detection, hindering a comprehensive understanding of the topic. We aim to fill this gap by providing a comprehensive SR of contemporary SRs covering different aspects of early detection of PCa in the European Union (EU) and the UK.

METHODS

On June 1, 2023, we searched four databases (Medline ALL via Ovid, Embase, Web of Science, and Cochrane Central Register of Controlled Trials) and Google Scholar. To avoid repetition of previous studies, only SRs (qualitative, quantitative, and/or MAs) were considered eligible. In the data, common themes were identified to present the evidence systematically.

KEY FINDINGS AND LIMITATIONS

We identified 1358 citations, resulting in 26 SRs eligible for inclusion. Six themes were identified: (1) invitation: men at general risk should be invited at >50 yr of age, and testing should be discontinued at >70 yr or with <10 yr of life expectancy; (2) decision-making: most health authorities discourage population-based screening and instead recommend a shared decision-making (SDM) approach, but implementation of SDM in clinical practice varies widely; decision aids help men make more informed and value-consistent screening decisions and decrease men's intention to attempt screening, but these do not affect screening uptake; (3) acceptance: facilitators for men considering screening include social prompting by partners and clinician recommendations, while barriers include a lack of knowledge, low-risk perception, and masculinity attributes; (4) screening test and algorithm: prostate-specific antigen-based screening reduces PCa-specific mortality and metastatic disease in men aged 55-69 yr at randomisation if screened at least twice; (5) harms and benefits: these benefits come at the cost of unnecessary biopsies, overdiagnosis, and subsequent overtreatment; and (6) future of screening: risk-adapted screening including (prebiopsy) risk calculators, magnetic resonance imaging, and blood- and urine-based biomarkers could reduce these harms. To enable a comprehensive overview, we focused on SRs. These do not include the most recent prospective studies, which were therefore incorporated in the discussion.

CONCLUSIONS AND CLINICAL IMPLICATIONS

By identifying consistent and conflicting evidence, this review highlights the evidence-based foundations that can be built upon, as well as areas requiring further research and improvement to reduce the burden of PCa in the EU and UK.

PATIENT SUMMARY

This review of 26 reviews covers various aspects of prostate cancer screening such as invitation, decision-making, screening tests, harms, and benefits. This review provides insights into existing evidence, highlighting the areas of consensus and discrepancies, to guide future research and improve prostate cancer screening strategies in Europe.

Understanding the Barriers to Prostate Cancer Population-Based Early Detection Programs: The PRAISE-U BEST Survey

In 2022, the European Commission updated its recommendation on cancer screening, inviting the Member States (MSs) to explore the feasibility of stepwise implementation of population-based screening for prostate cancer (PCa). In line with this recommendation, the PRAISE-U (Prostate Cancer Awareness and Initiative for Screening in the European Union (EU)) project was initiated. As part of the PRAISE-U, we aim to understand the current practice towards early detection in the EU MSs, the barriers to implementing or planning population-based screening programmes, and potential solutions to overcome these barriers.

METHODS

We adapted the Barriers to Effective Screening Tool (BEST) survey to the PCa context. However, it has not been validated in this context. We translated it into all spoken languages in the EU27 and disseminated it to different stakeholders across the EU using a snowballing approach.

RESULTS

We received 410 responses from 55 countries, of which 301 (73%) were from the 27 EU MSs. The most represented stakeholder group was urologists (218 (54%)), followed by general practitioners (GPs) (83 (21%)), patient representatives (35 (9%)), policy stakeholders (27 (7%)), researchers (23 (6%)), oncologists, pathologists, radiologists, nurses, and others (16 (4%)) and one industry representative. Among all respondents, 286 (69%) reported the absence of a population-based screening programme, mainly attributed to resource limitations and a lack of political and medical society support. Out of these 286 respondents, 196 (69%) indicated that opportunistic screening is being applied in their country, and 199 (70%) expressed their support for population-based screening programmes (which was highest amongst patient representatives and urologists and lowest amongst GPs and policy stakeholders). The highest scored barriers were lack of political support, insufficient operational resources, and inadequate participation. Suggested solutions to overcome these included awareness campaigns, consensus meetings, political lobbying and European guidelines (to overcome political support barriers), compatible IT systems (to overcome operational barriers), and easy access (to overcome participation barriers).

CONCLUSIONS

Participants have noted the presence of opportunistic screening, and particularly urologists and patient representatives expressed their support for the establishment of a population-based PCa screening programme. Nevertheless, successful implementation of population-based screening programmes is complex; it requires political and medical society support, operational resources and capacity, awareness campaigns, as well as the development of protocols, guidelines, and legal frameworks.

Evolution of European prostate cancer screening protocols and summary of ongoing trials

Population-based organised repeated screening for prostate cancer has been found to reduce disease-specific mortality, but with substantial overdiagnosis leading to overtreatment. Although only very few countries have implemented a screening programme on a national level, individual prostate-specific antigen (PSA) testing is common. This opportunistic testing may have little favourable impact, while stressing the side-effects. The classic early detection protocols as were state-of-the-art in the 1990s applied a PSA and digital rectal examination threshold for sextant systematic prostate biopsy, with a fixed interval for re-testing, and limited indication for expectant management. In the three decades since these trials were started, different important improvements have become available in the cascade of screening, indication for biopsy, and treatment. The main developed aspects include: better identification of individuals at risk (using early/baseline PSA, family history, and/or genetic profile), individualised re-testing interval, optimised and individualised starting and stopping age, with gradual invitation at a fixed age rather than invitation of a wider range of age groups, risk stratification for biopsy (using PSA density, risk calculator, magnetic resonance imaging, serum and urine biomarkers, or combinations/sequences), targeted biopsy, transperineal biopsy approach, active surveillance for low-risk prostate cancer, and improved staging of disease. All these developments are suggested to decrease the side-effects of screening, while at least maintaining the advantages, but Level 1 evidence is lacking. The knowledge gained and new developments on early detection are being tested in different prospective screening trials throughout Europe. In addition, the European Union-funded PRostate cancer Awareness and Initiative for Screening in the European Union (PRAISE-U) project will compare and evaluate different screening pilots throughout Europe. Implementation and sustainability will also be addressed. Modern screening approaches may reduce the burden of the second most frequent cause of cancer-related death in European males, while minimising side-effects. Also, less efficacious opportunistic early detection may be indirectly reduced.

Risk of Clinically Significant Prostate Cancer after a Nonsuspicious Prostate MRI-A Comparison with the General Population

BACKGROUND

We compare the risk of clinically significant (csPCa; ISUP Grade Group ≥ 2) and insignificant prostate cancer (isPCa; ISUP Grade Group 1) in men with a nonsuspicious prostate MRI (nMRI; PI-RADS ≤ 2) with the general population, and assess the value of PSA density (PSAD) in stratification.

METHODS

In this retrospective population-based cohort study we identified 1,682 50-79-year-old men, who underwent nMRI at HUS (2016-2019). We compared their age-standardized incidence rates (IR) of csPCa and the odds of isPCa to a local age- and sex-matched general population (n = 230,458) during a six-year follow-up. Comparisons were performed by calculating incidence rate ratios (IRR) and ORs with 95% confidence intervals (CI). We repeated the comparison for the 920 men with nMRI and PSAD < 0.15 ng/mL/cm3.

RESULTS

Compared with the general population, the IR of csPCa was significantly higher after nMRI [1,852 vs. 552 per 100,000 person-years; IRR 3.4 (95% CI, 2.8-4.1)]. However, the IR was substantially lower if PSAD was low [778 per 100,000 person-years; IRR 1.4 (95% CI, 0.9-2.0)]. ORs for isPCa were 2.4 (95% CI, 1.7-3.5) for all men with nMRI and 5.0 (95% CI, 2.8-9.1) if PSAD was low.

CONCLUSIONS

Compared with the general population, the risk of csPCa is not negligible after nMRI. However, men with nMRI and PSAD <0.15 ng/mL/cm3 have worse harm-benefit balance than men in the general population.

IMPACT

Prostate biopsies for men with nMRI should be reserved for cases indicated by additional risk stratification. See related In the Spotlight, p. 641.

The impact of pre-biopsy MRI and additional testing on prostate cancer screening outcomes: A rapid review

Objective

This work aims to examine the latest evidence on the impact of pre-biopsy MRI, in addition to prostate-specific antigen (PSA) testing, on health outcomes and quality of life.

Methods

We conducted a literature search including PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) databases, with a limited scan of (i) guidelines and (ii) references from trial reports, from January 2005 to 25th January 2023. Two independent reviewers selected randomised controlled trials (RCT) and cohort studies which met our inclusion criteria.

Results

One hundred thirty-seven articles were identified, and seven trial articles were selected. Trial interventions were as follows: (i) PSA blood test, (ii) additional tests such as pre-biopsy multiparametric magnetic resonance imaging (mpMRI) and Biparametric MRI (bpMRI), and (iii) MRI targeted biopsy and standard biopsy. Compared with standard biopsy, MRI-based interventions led to increased detection of clinically significant cancers in three studies and decreased detection of clinically insignificant cancer (Gleason grade 3 + 3) in four studies. However, PROstate Magnetic resonance Imaging Study (PROMIS) and Stockholm3 with MRI (STHLM3-MRI) studies reported different trends depending on the scenario studied in PROMIS (MRI triage and MRI directed biopsy vs. MRI triage and standard biopsy) and thresholds used in STHLM3-MRI (≥0·11 and ≥0·15). MRI also helped 8%-49% of men avoid biopsy, in six out of seven studies, but not in STHLM3-MRI at ≥0.11. Interestingly, the proportion of men who experienced sepsis and UTI was low across studies.

Conclusion

This review found that a combination of approaches, centred on the use of pre-biopsy MRI, may improve the detection of clinically significant cancers and reduce (i) the diagnosis of clinically insignificant cancers and (ii) unnecessary biopsies, compared with PSA testing and standard biopsy alone. However, the impact of such interventions on longer term outcomes such as prostate cancer-specific mortality has not yet been assessed.

Histomic and transcriptomic features of MRI-visible and invisible clinically significant prostate cancers are associated with prognosis

Magnetic resonance imaging (MRI) is increasingly used to triage patients for prostate biopsy. However, 9% to 24% of clinically significant (cs) prostate cancers (PCas) are not visible in MRI. We aimed to identify histomic and transcriptomic determinants of MRI visibility and their association to metastasis, and PCa-specific death (PCSD). We studied 45 radical prostatectomy-treated patients with csPCa (grade group [GG]2-3), including 30 with MRI-visible and 15 with MRI-invisible lesions, and 18 men without PCa. First, histological composition was quantified. Next, transcriptomic profiling was performed using NanoString technology. MRI visibility-associated differentially expressed genes (DEGs) and Reactome pathways were identified. MRI visibility was classified using publicly available genes in MSK-IMPACT and Decipher, Oncotype DX, and Prolaris. Finally, DEGs and clinical parameters were used to classify metastasis and PCSD in an external cohort, which included 76 patients with metastatic GG2-4 PCa, and 84 baseline-matched controls without progression. Luminal area was lower in MRI-visible than invisible lesions and low luminal area was associated with short metastasis-free and PCa-specific survival. We identified 67 DEGs, eight of which were associated with survival. Cell division, inflammation and transcriptional regulation pathways were upregulated in MRI-visible csPCas. Genes in Decipher, Oncotype DX and MSK-IMPACT performed well in classifying MRI visibility (AUC = 0.86-0.94). DEGs improved classification of metastasis (AUC = 0.69) and PCSD (AUC = 0.68) over clinical parameters. Our data reveals that MRI-visible csPCas harbor more aggressive histomic and transcriptomic features than MRI-invisible csPCas. Thus, targeted biopsy of visible lesions may be sufficient for risk stratification in patients with a positive MRI.

Prostate tumor markers: diagnosis, prognosis and management

Prostate cancer (PCA) is the second most common type of cancer in the world. Nevertheless, diagnosis is still based on nonspecific methods, or invasive methods which makes clinical decision and diagnosis difficult, generating risk of both underdiagnosis and overdiagnosis. Given the high prevalence, morbidity and mortality of PCA, new strategies are needed for its diagnosis. A review of the literature on available biomarkers for PCA was performed, using the following terms: prostate cancer AND marker OR biomarker. The search was carried out in Pubmed, Science Direct, Web of Science and Clinical Trial. A total of 35 articles were used, and PHI (Prostate Health Index) and the 4Kscore tests were identified as the best well-established serum markers. These tests are based on the evaluation of expression levels of several molecules. For analysis of urine samples, Progensa, ExoDXProstate, and Mi Prostate Score Urine Test are available. All these tests have the potential to help diagnosis, avoiding unnecessary biopsies, but they are used only in association with digital rectal examination and PSA level data. The search for biomarkers that can help in the diagnosis and therapeutic management of PCA is still in its initial phase, requiring more efforts for an effective clinical application.

A pilot study of an organised population-based testing programme for prostate cancer

OBJECTIVE

To determine the feasibility of a digitally automated population-based programme for organised prostate cancer testing (OPT) in Southern Sweden.

PATIENTS AND METHODS

A pilot project for a regional OPT was conducted between September 2020 and February 2021, inviting 999 randomly selected men aged 50, 56, or 62 years. Risk stratification was based on prostate-specific antigen (PSA) level, PSA density (PSAD), and bi-parametric prostate magnetic resonance imaging (MRI). Men with a PSA level of 3-99 ng/mL had an MRI, and men with elevated PSA level (≥3 ng/mL) had a urological check-up, including a digital rectal examination and transrectal ultrasonography (TRUS). Indications for targeted and/or systematic transrectal prostate biopsies were suspicious lesions on MRI (Prostate Imaging-Reporting and Data System [PI-RADS] 4-5) and/or PSAD > 0.15 ng/mL/mL. Additional indications for prostate biopsies were palpable tumours, PSA ratio < 0.1, or cancer suspicion on TRUS. Patient selection, mail correspondence, data collection, and algorithm processing were performed by an automated digital management system. Feasibility is reported descriptively.

RESULTS

A total of 418 men had a PSA test (42%), with increasing participation rates by age (50 years, 38%; 56 years, 44%; and 62 years, 45%). Among these, 35 men (8%) had elevated PSA levels (≥3 ng/mL: one of 139, aged 50 years; 10/143, aged 56 years; and 24/146, aged 62 years). On MRI, 16 men (48%) had a negative scan (PI-RADS < 3), seven men (21%) had PI-RADS 3, nine men (27%) had PI-RADS 4, and one man (3%) had PI-RADS 5. All men with PI-RADS 4 or 5 underwent prostate biopsies, as well as two men with PI-RADS 3 due to PSAD > 0.15 ng/mL/mL or a suspicious finding on TRUS. Prostate cancer was diagnosed in 10 men. Six men underwent active treatment, whereas four men were assigned to active surveillance.

CONCLUSION

Our OPT model is feasible from an operational point of view, but due to the limited scale of this study no conclusions can be made regarding the efficacy of the diagnostic model or outcome.

Relationship Between Baseline Prostate-specific Antigen on Cancer Detection and Prostate Cancer Death: Long-term Follow-up from the European Randomized Study of Screening for Prostate Cancer

BACKGROUND

The European Association of Urology guidelines recommend a risk-based strategy for prostate cancer screening based on the first prostate-specific antigen (PSA) level and age.

OBJECTIVE

To analyze the impact of the first PSA level on prostate cancer (PCa) detection and PCa-specific mortality (PCSM) in a population-based screening trial (repeat screening every 2-4 yr).

DESIGN, SETTING, AND PARTICIPANTS

We evaluated 25589 men aged 55-59 yr, 16898 men aged 60-64 yr, and 12936 men aged 65-69 yr who attended at least one screening visit in the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial (screening arm: repeat PSA testing every 2-4 yr and biopsy in cases with elevated PSA; control arm: no active screening offered) during 16-yr follow-up (FU).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We assessed the actuarial probability for any PCa and for clinically significant (cs)PCa (Gleason ≥7). Cox proportional-hazards regression was performed to assess whether the association between baseline PSA and PCSM was comparable for all age groups. A Lorenz curve was computed to assess the association between baseline PSA and PCSM for men aged 60-61 yr.

RESULTS AND LIMITATIONS

The overall actuarial probability at 16 yr ranged from 12% to 16% for any PCa and from 3.7% to 5.7% for csPCa across the age groups. The actuarial probability of csPCa at 16 yr ranged from 1.2-1.5% for men with PSA <1.0 ng/ml to 13.3-13.8% for men with PSA ≥3.0 ng/ml. The association between baseline PSA and PCSM differed marginally among the three age groups. A Lorenz curve for men aged 60-61 yr showed that 92% of lethal PCa cases occurred among those with PSA above the median (1.21 ng/ml). In addition, for men initially screened at age 60-61 yr with baseline PSA <2 ng/ml, further continuation of screening is unlikely to be beneficial after the age of 68-70 yr if PSA is still <2 ng/ml. No case of PCSM emerged in the subsequent 8 yr (up to age 76-78 yr). A limitation is that these results may not be generalizable to an opportunistic screening setting or to contemporary clinical practice.

CONCLUSIONS

In all age groups, baseline PSA can guide decisions on the repeat screening interval. Baseline PSA of <1.0 ng/ml for men aged 55-69 yr is a strong indicator to delay or stop further screening.

PATIENT SUMMARY

In prostate cancer screening, the patient's baseline PSA (prostate-specific antigen) level can be used to guide decisions on when to repeat screening. The PSA test when used according to current knowledge is valuable in helping to reduce the burden of prostate cancer.

Designing and Implementing a Population-based Organised Prostate Cancer Testing Programme

BACKGROUND

European guidelines recommend that well-informed men at elevated risk of having prostate cancer (PCa) should be offered prostate-specific antigen (PSA) testing with risk-stratified follow-up. The Swedish National Board of Health and Welfare recommends against screening for PCa but supports regional implementation of organised prostate cancer testing (OPT).

OBJECTIVE

To report the process for designing and implementing OPT programmes.

DESIGN, SETTING, AND PARTICIPANTS

Population-based OPT programmes in two Swedish regions, designed to include men aged between 50 and 74 yr, launched in September 2020 for 50-yr-old men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The number of men invited, the participation rate, and the numbers of magnetic resonance imaging (MRI) scans, urological visits, and biopsies from September 2020 to June 2021 were recorded.

RESULTS AND LIMITATIONS

Two Swedish regions co-designed an OPT programme with a risk-stratified diagnostic algorithm based on prostate-specific antigen (PSA), PSA density, MRI findings, and age. An automated administrative system was developed on a nationwide web-based platform. Invitation letters and test results are automatically generated and sent out by post. Men with PSA ≥3ng/ml, a suspicious MRI lesion, and/or PSA density ≥0.15 ng/ml/cm³ are referred for a prostate biopsy. Test results are registered for quality control and research. By June 2021, a total of 16 515 men were invited, of whom 6309 (38%) participated; 147 had an MRI scan and 39 underwent prostate biopsy. The OPT framework, algorithm, and diagnostic pathways have been working well.

CONCLUSIONS

We designed and implemented a framework for OPT with a high grade of automation. The framework and organisational experiences may be of value for others who plan a programme for early detection of PCa.

PATIENT SUMMARY

We describe the implementation of an organised testing programme for early detection of prostate cancer in two Swedish regions. This model is the first of its kind and may serve as a template for similar programmes.