Which men benefit from prostate cancer screening? Prostate cancer mortality by subgroup in the European Randomised Study of Screening for Prostate Cancer.

OBJECTIVE: To evaluate whether a subgroup of men can be identified that would benefit more from screening than others. MATERIALS AND METHODS: This retrospective cohort study was based on three European Randomised Study of Screening for Prostate Cancer (ERSPC) centres, Finland, the Netherlands and Sweden. We identified 126 827 men aged 55-69 years in the study who were followed for maximum of 16 years after randomisation. The primary outcome was prostate cancer (PCa) mortality. We analysed three age groups 55-59, 60-64 and 65-69 years and PCa cases within four European Association of Urology (EAU) risk groups: low, intermediate, high risk, and advanced disease. RESULTS: The hazard ratio (HR) for PCa mortality in the screening arm relative to the control arm for men aged 55-59 years was 0.96 (95% confidence interval [CI] 0.75-1.24) in Finland, 0.70 (95% CI 0.44-1.12) in the Netherlands and 0.42 (95% CI 0.24-0.73) in Sweden. The HR for men aged 60-64 years was 1.03 (95% CI 0.77-1.37) in Finland, 0.76 (95% CI 0.50-1.16) in the Netherlands and 0.97 (95% CI 0.64-1.48) in Sweden. The HR for men aged 65-69 years was 0.80 (95% CI 0.62-1.03) in Finland and 0.57 (95% CI 0.38-0.83) in the Netherlands, and this age group was absent in Sweden. In the EAU risk group analysis, PCa mortality rates were materially lower for men with advanced disease at diagnosis in all three countries: 0.67 (95% CI 0.56-0.82) in Finland, 0.28 (95% CI 0.18-0.44) in the Netherlands, and 0.48 (95% CI 0.30-0.78) in Sweden. CONCLUSION: We were unable to unequivocally identify the optimal age group for screening, as mortality reduction differed among centres and age groups. Instead, the screening effect appears to depend on screening duration, and the number and frequency of screening rounds. PCa mortality reduction by screening is largely attributable to stage shift.

[Prostate cancer - diagnostics and screening]. / Prostatacancer ­ utredning, klinisk diagnostik och screening.

Prostate-specific antigen (PSA) based screening is controversial, even though randomised trials show that screening can reduce prostate cancer mortality. The main reason is that screening leads to overdiagnosis of indolent cancers that would never have surfaced clinically in the absence of screening. Recently, several large studies have shown that magnetic resonance imaging (MRI) improves prostate cancer diagnostics. With MRI, up to half of all men with elevated PSA values can be spared a biopsy. When a biopsy is needed, the needles can be directed towards the suspicious area in the prostate, which increases the detection of clinically significant tumors. In Sweden, regional programmes with organised prostate cancer testing were introduced in 2020. These programmes aim to make prostate cancer testing more standardized, efficient, and equitable. In the future, biomarkers and AI-based systems will likely be important to further improve prostate cancer diagnostics.

Prostate Cancers in the Prostate-specific Antigen Interval of 1.8-3 ng/ml: Results from the Göteborg-2 Prostate Cancer Screening Trial.

BACKGROUND: Magnetic resonance imaging (MRI) and targeted biopsies reduce overdiagnosis of prostate cancer (PC). It is uncertain how this strategy performs for low prostate-specific antigen (PSA) levels. OBJECTIVE: To investigate the Prostate Imaging Reporting and Data System (PI-RADS) distribution, frequency, and characteristics of screen-detected PC with PSA of 1.8-<3 ng/ml and 3-<10 ng/ml. DESIGN, SETTING, AND PARTICIPANTS: In the population-based Göteborg-2 screening study, 17974 men choose to participate by having a PSA test (2015-2020). One-third of the participants (n = 6006) were randomized to arm 3, men with a PSA value of ≥1.8 ng/ml were recommended for MRI. Men with positive MRI (PI-RADS 3-5) had four targeted biopsies from each MRI-visible lesion. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Clinically significant PC was defined as Gleason score ≥3 + 4. RESULTS AND LIMITATIONS: A total of 6006 men were included. The median age was 55.9 yr (interquartile range [IQR] 52.6-59.6). Of them, 4929 (82%) had PSA of <1.8 ng/ml, 670 (11%) had PSA of 1.8-<3 ng/ml (low-PSA group, median PSA 2.1 ng/ml [IQR 1.9-2.5]), and 377 (6.3%) had PSA of 3-<10 ng/ml (high-PSA group, median PSA 3.9 ng/ml [IQR 3.3-5.0]). PI-RADS scores of 3, 4, and 5 were observed in 7.8%, 15%, and 1.0% of men in the low-PSA group, and in 6.9%, 17%, and 5.3% of men in the high-PSA group, respectively. PC was found in 64 men (41%, 95% confidence interval [CI] 0.33-0.49) with positive MRI findings in the low-PSA group, of whom 33 (21%) had Gleason 6 (insignificant PC) and 31 (20%) had Gleason ≥7 (significant PC). In the high-PSA group, PC was detected in 61 men (56%, 95% CI 0.46-0.66), of whom 26 (24%) had Gleason 6 (insignificant PC) and 35 (32%) had Gleason ≥7 (significant PC). Limitations include results from only a single screening round. CONCLUSIONS: A non-negligible number of men with PSA 1.8-3 ng/ml have clinically significant PC. Whether a delay in the diagnosis of these tumors until they reached PSA ≥3 ng/ml would impair their chance of cure remains to be evaluated. PATIENT SUMMARY: We studied screening using prostate-specific antigen (PSA) and magnetic resonance imaging in men with PSA 1.8-3 ng/ml. We found a non-negligible number of potentially harmful prostate cancers in these men.

Young Age on Starting Prostate-specific Antigen Testing Is Associated with a Greater Reduction in Prostate Cancer Mortality: 24-Year Follow-up of the Göteborg Randomized Population-based Prostate Cancer Screening Trial.

BACKGROUND: The risk of death from prostate cancer (PC) depends on age, but the age at which to start prostate-specific antigen (PSA) screening remains uncertain. OBJECTIVE: To study the relationship between risk reduction for PC mortality and age at first PSA screening. DESIGN, SETTING, AND PARTICIPANTS: The randomized Göteborg-1 trial invited men for biennial PSA screening between the ages of 50 and 70 yr (screening, n = 10 000) or no invitation but exposure to opportunistic PSA testing (control, n = 10 000). INTERVENTION: Regular versus opportunistic PSA screening or no PSA. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We modeled the nonlinear association between starting age and the absolute risk reduction in PC mortality in three settings: (1) intention-to-screen (randomized arms); (2) historical control (screening group and 1990-1994 registry data); and (3) attendees only (screening attendees and matched controls). We tested whether the effect of screening on PC mortality depends on the age at starting screening by comparing survival models with and without an interaction between trial arm and age (intention-to-screen and attendees only). RESULTS AND LIMITATIONS: Younger age on starting PSA testing was associated with a greater reduction in PC mortality. Starting screening at age 55 yr approximately halved the risk of PC death compared to first PSA at age 60 yr. The test of association between starting age and the effect of screening on PC mortality was slightly greater than the conventional level of statistical significance (p = 0.052) for the entire cohort, and statistically significant among attendees (p = 0.002). This study is limited by the low number of disease-specific deaths for men starting screening before age 55 yr and the difficulty in discriminating between the effect of starting age and screening duration. CONCLUSIONS: Given that prior screening trials included men aged up to 70 yr on starting screening, our results suggest that the effect size reported in prior trials underestimates that of currently recommended programs starting at age 50-55 yr. PATIENT SUMMARY: In this study from the Göteborg-1 trial, we looked at the effect of prostate-specific antigen (PSA) screening in reducing men's risk of dying from prostate cancer given the age at which they begin testing. Starting at a younger age reduced the risk of prostate cancer death by a greater amount. We recommend that PSA screening should start no later than at age 55 yr.

Surgeon volume and patient-reported urinary incontinence after radical prostatectomy. Population-based register study in Sweden.

OBJECTIVE: To investigate the association between surgeon volume and urinary incontinence after radical prostatectomy. METHODS: A total of 8326 men in The National Prostate Cancer Register of Sweden (NPCR) underwent robot-assisted radical prostatectomy (RARP) between 2017 and 2019 of whom 56% (4668/8 326) had responded to a questionnaire one year after RARP. The questionnaire included the question: 'How much urine leakage do you experience?' with the response alternatives 'Not at all', 'A little', defined as continence and 'Moderately', 'Much/Very much' as incontinence. Association between incontinence and mean number of RARPs/year/surgeon was analysed with multivariable logistic regression including age, Charlson Comorbidity Index (CCI), PSA, prostate volume, number of biopsy cores with cancer, cT stage, Gleason score, lymph node dissection, nerve sparing intent and response rate to the questionnaire. RESULTS: 14% (659/4 668) of the men were incontinent one year after RARP. There was no statistically significant association between surgeon volume and incontinence. Older age (>75 years vs. < 65 years, OR 2.29 [95% CI 1.48-3.53]), higher CCI (CCI 2+ vs. CCI 0, OR 1.37 [95% CI 1.04-1.80]) and no nerve sparing intent (no vs. yes OR 1.53 [95% CI 1.26-1.85]) increased risk of incontinence. There were large differences in the proportion of incontinent men between surgeons with similar annual volumes, which remained after adjustment. CONCLUSIONS: The lack of association between surgeon volume and incontinence and the wide range in outcome between surgeons with similar volumes underline the importance of individual feedback to surgeons on functional results.

Biochemical recurrence after radical prostatectomy - a large, comprehensive, population-based study with long follow-up.

OBJECTIVE: We evaluated long-term risk for biochemical recurrence and subsequent prognosis in a population-based cohort. MATERIAL AND METHODS: We used register-based data to evaluate 6 675 consecutive patients having radical prostatectomy in Västra Götaland county in Sweden during 1995-2014. Patients were followed until death or end of study, 31 December 2014. Data were collected from registers on national, regional and local level and linked by means of the Swedish personal identity number. Biochemical recurrence was defined as PSA ≥0.2 ng/ml; failure as hormonal treatment, metastasis or prostate cancer death. Survival analysis was used to estimate time to biochemical recurrence and time to failure after biochemical recurrence for patients with 0 - 2 years, 2-5 years, 5-10 years and >10 years interval to biochemical recurrence, respectively. RESULTS: A total of 1214 men had biochemical recurrence during follow-up. Biochemical recurrence-free survival was 83% (95% confidence interval [CI] 82-84%), 75% (95% CI 74-77%) and 69% (95% CI 67-71%) at 5, 10 and 15 years, respectively. Cumulative incidence of failure for all patients 15 years after biochemical recurrence was 50% (95% CI 43-55%) in competing risk analysis. The risk of failure after biochemical recurrence was highest among patients having biochemical recurrence within 2 years from surgery. Incomplete data on PSA-history is a limitation. CONCLUSIONS: The risk for biochemical recurrence persists 15 years after surgery. Follow-up should continue as long as treatment would be considered in case of recurrent disease.

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.

Prostate Cancer Screening with Magnetic Resonance Imaging: Results from the Second Round of the Göteborg Prostate Cancer Screening 2 Trial.

BACKGROUND: The Göteborg 2 prostate cancer (PC) screening (G2) trial evaluates screening with prostate-specific antigen (PSA) followed by magnetic resonance imaging (MRI) in case of elevated PSA levels. OBJECTIVE: To assess the safety of using a 2-yr interval in men who were previously screened positive with PSA but had negative MRI or positive MRI with a negative biopsy. DESIGN, SETTING, AND PARTICIPANTS: A total of 61 201 men aged 50-60 yr were randomized and 38 366 were invited for screening (years 2015-2020). Men with positive MRI (Prostate Imaging Reporting and Data System [PI-RADS] score ≥3) were scheduled for targeted biopsies. Men with negative MRI or negative biopsies were reinvited after 2 yr. Round 1 and 2 MRI scans (PI-RADS ≥3) of men not diagnosed with PC in round 1 were re-read and classified according to Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) by two radiologists. Interval PCs (detected outside the program before invitation to round 2) were identified by linking to the Regional PC Registry. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Tabulation of overall detection of PC was done. RESULTS AND LIMITATIONS: Between October 2017 and June 2020, 474 men with round 1 elevated PSA and MRI underwent a second screening. Of those, 19% had nonelevated PSA in round 2 and were not examined further. Of the remaining 376 men, 89% had negative MRI. Targeted biopsies yielded 14 PCs: nine grade group (GG) 1 and five GG 2-3. In men with PI-RADS ≥3 and PC diagnosed in round 2, only two (GG 1) progressed according to the PRECISE criteria and the remainder were stable. Ten interval PCs were diagnosed: seven GG 1, one GG 2, and two GG 5. The two GG 5 PCs were PI-RADS 4 and 5 with negative round 1 biopsy. CONCLUSIONS: A 2-yr interval seems to be safe in men with negative MRI, while men with PI-RADS 4 and 5 lesions with negative biopsies should have a closer follow-up. PATIENT SUMMARY: In prostate cancer screening, a 2-yr follow-up seems to be safe if magnetic resonance imaging did not show highly suspicious findings.

Constitutive expression of inducible nitric oxide synthase in healthy rat urothelium?

BACKGROUND: Contrasting findings have been reported regarding a possible constitutive expression of inducible nitric oxide synthase (iNOS) in a normal mammalian bladder. The current study was designed to further investigate such putative iNOS expression. MATERIALS AND METHODS: The experiments were conducted with paraffin-embedded archival material from the urinary bladder of 6 normal, male Sprague-Dawley rats. In addition, two normal female mice (C57BL/6) were sacrificed and the urinary bladders were harvested. The occurrence of iNOS mRNA was examined by the RNAScope in situ hybridization method. Protein expression of iNOS and 3-nitrotyrosine (the latter used as an indicator of oxidative stress) was investigated by immunohistochemistry. RESULTS: No expression of iNOS mRNA was observed in the bladder tissue. iNOS protein and 3-nitrotyrosine were strongly expressed in the urothelium. iNOS was also expressed perinuclearly in the detrusor. CONCLUSIONS: Although the RNAScope methodology could not demonstrate mRNA for iNOS in the normal urinary bladder, the results by immunohistochemistry strongly suggest the occurrence of iNOS in particular, in the urothelium. Positive reactivity for 3-nitrotyrosine may indicate ongoing oxidative stress of the urothelium. The finding of perinuclear iNOS immunoreactivity could suggest an intracrine signaling function by iNOS to the nucleus.

Bi- or multiparametric MRI in a sequential screening program for prostate cancer with PSA followed by MRI? Results from the Göteborg prostate cancer screening 2 trial.

OBJECTIVES: The PIRADS Steering Committee has called for "higher quality data before making evidence-based recommendations on MRI without contrast enhancement as an initial diagnostic work up," however, recognizing biparametric (bp) MRI as a reasonable option in a low-risk setting such as screening. With bpMRI, more men can undergo MRI at a lower cost and they can be spared the invasiveness of intravenous access. The aim of this study was to assess cancer detection in bpMRI vs mpMRI in sequential screening for prostate cancer (PCa). METHODS: Within the ongoing Göteborg PCa screening 2 trial, we assessed cancer detection in 551 consecutive participants undergoing prostate MRI. In the same session, readers first assessed bpMRI and then mpMRI. Four targeted biopsies were performed for lesions scored PIRADS 3-5 with bpMRI and/or mpMRI. RESULTS: Cancer was detected in 84/551 cases (15.2%; 95% CI: 12.4-18.4) with mpMRI and in 83/551 cases (15.1%; 95% CI: 12.3-18.2%) with bpMRI. The relative risk (RR) for cancer detection with bpMRI compared to mpMRI was 0.99 (95% one-sided CI: > 94.8); bpMRI was non-inferior to mpMRI (10% non-inferiority margin). bpMRI resulted in fewer false positives, 45/128 (35.2%), compared to mpMRI, 52/136 (38.2%), RR = 0.92; 95% CI: 0.84-0.98. Of 8 lesions scored positive only with mpMRI, 7 were false positives. The PPV for MRI and targeted biopsy was 83/128 (64.8%) for bpMRI and 84/136 (61.8%) for mpMRI, RR = 1.05, 95% CI: 1.01-1.10. CONCLUSIONS: In a PSA-screened population, bpMRI was non-inferior to mpMRI for cancer detection and resulted in fewer false positives. KEY POINTS: • In screening for prostate cancer with PSA followed by MRI, biparametric MRI allows radiologists to detect an almost similar number of prostate cancers and score fewer false positive lesions compared to multiparametric MRI. • In a screening program, high sensitivity should be weighed against cost and risks for healthy men; a large number of men can be saved the exposure of gadolinium contrast medium by adopting biparametric MRI and at the same time allowing for a higher turnover in the MRI room.

The GÖTEBORG prostate cancer screening 2 trial: a prospective, randomised, population-based prostate cancer screening trial with prostate-specific antigen testing followed by magnetic resonance imaging of the prostate.

OBJECTIVE: To describe the study design of the GÖTEBORG prostate cancer screening (PC) 2 (Göteborg-2), a prospective, randomised, population-based trial of PC screening. This trial evaluates whether prostate-specific antigen (PSA) testing followed by 3 Tesla prostate magnetic resonance imaging (MRI) and targeted biopsy can reduce overdiagnosis, while maintaining the detection of clinically significant cancer, compared to PSA-screening and systematic biopsy. MATERIALS AND METHODS: A random sample of men 50-60 years in the Göteborg area, Sweden, identified from the Total Population Register, were randomised to either a screening or control group (CG). Participants in the screening group (SG) were further randomised into one of three arms: (1) PSA-test; if PSA ≥ 3 ng/mL, then MRI and systematic biopsy, plus targeted biopsy to suspicious lesions as per Prostate Imaging - Reporting and Data System, version 2 (PI-RADSv2) 3-5; (2) PSA-test; if PSA ≥ 3 ng/mL, then MRI, and targeted biopsy only if PI-RADSv2 3-5; (3) identical to Arm 2, except lower PSA-cut-off ≥1.8 ng/mL. The primary outcome is the detection rate of clinically insignificant PC (defined as Gleason Score 3 + 3 [Grade Group 1]) comparing all men with PSA ≥ 3 ng/mL in Arm 1 vs. Arm 2 + 3. RESULTS: Randomisation and enrolment started in September 2015. Accrual has hitherto resulted in 38,770 men randomised to the SG. The participation rate is 50%. Invitation to the first screening round was completed in June 2020. CONCLUSIONS: The Göteborg-2 trial will provide new knowledge about the performance of prostate MRI in a screening setting.

Long-term Outcomes for Men in a Prostate Screening Trial with an Initial Benign Prostate Biopsy: A Population-based Cohort.

BACKGROUND: The optimal follow-up regimen for men after a benign prostate biopsy remains unknown. OBJECTIVE: To investigate long-term outcomes for men after an initial benign prostate biopsy. DESIGN, SETTING, AND PARTICIPANTS: All men with a benign biopsy in the first screening round of the Göteborg prostate cancer (PC) screening trial were included. The follow-up period was January 1, 1995-May 15, 2017. INTERVENTION: Prostate-specific antigen (PSA) tests were performed every second year (upper median age limit 69yr). Men with PSA ≥3ng/ml underwent prostate biopsy (sextant biopsy up to 2009). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The 20-yr cumulative PC incidence and PC mortality were calculated using the 1 minus Kaplan-Meier method. RESULTS AND LIMITATIONS: Of 452 men with a benign biopsy and followed for a median of 21.1yr, 169 were diagnosed with PC and five died from PC. The 20-yr cumulative PC incidence and PC mortality were 40.0% and 1.4%, respectively. The corresponding figures were 38.8% and 0.6% for men with initial PSA ≤10ng/ml, and 64.4% and 21.4% for PSA >10ng/ml. The proportion of men untreated at final follow-up was similar in the two PSA groups (22% vs 23%). The use of sextant biopsy for many years of the trial is a limitation. CONCLUSIONS: Men with an initial benign prostate biopsy run a very low risk of dying from PC when participating in a screening program. However, if followed for a long period, many men will be diagnosed and treated for PC. Low-intensity follow-up, as in the Göteborg trial, appears sufficient for men with PSA ≤10ng/ml after a benign biopsy. PATIENT SUMMARY: This study shows that men who participate in a prostate cancer screening trial have a low risk of dying from prostate cancer if the first biopsy does not show cancer.

Prostate cancer risk assessment in men with an initial P.S.A. below 3 ng/mL: results from the Göteborg randomized population-based prostate cancer screening trial.

OBJECTIVE: To evaluate the long-term outcome of men with an initial prostate-specific antigen (PSA) level below 3 ng/mL and whether the free-to-total (F/T PSA) ratio is a useful prognostic marker in this range. MATERIALS AND METHODS: This study is based on 5,174 men aged 50-66 years, who in 1995-1996 participated in the first round of the Göteborg randomized screening trial (initial T-PSA level <3 ng/mL). These men were subsequently invited biennially for PSA and F/T PSA screening until they reached the upper age limit (on average 69 years). Biopsy was recommended if PSA ≥ 3 ng/mL. RESULTS: After a median follow-up of 18.9 years, 754 men (14.6%) were diagnosed with prostate cancer (PC). The overall cumulative PC incidence was 17.2%. It increased from 7.9% among men with T-PSA of ≤0.99 ng/mL to 26.0% in men with T-PSA levels of 1-1.99 ng/mL and 40.3% in men between 2-2.99 ng/mL (p < 0.001). The initial PSA was also related to the incidence of Gleason ≥7 PC (3.7% vs 9.7% vs 10.9%) and PC death (0.3% vs 1.1% vs 1.5%). Adding F/T PSA did not improve PC prediction in terms of Harrell concordance index (base model 0.76 vs 0.76) nor improvement of the likelihood of the model (p = 0.371). CONCLUSIONS: Some men with initial PSA < 3 ng/mL will be diagnosed too late, despite participating in an organized screening program, indicating that prompt diagnosis is justified in these men. PC incidence and risk of PC death was associated with PSA., but F/T PSA had no predictive value.

Opportunistic testing versus organized prostate-specific antigen screening: outcome after 18 years in the Göteborg randomized population-based prostate cancer screening trial.

BACKGROUND: It has been shown that organized screening decreases prostate cancer (PC) mortality, but the effect of opportunistic screening is largely unknown. OBJECTIVE: To compare the ability to reduce PC mortality and the risk of overdiagnosis between organized and opportunistic screening. DESIGN, SETTING, AND PARTICIPANTS: The Göteborg screening study invited 10 000 randomly selected men for prostate-specific antigen (PSA) testing every 2 yr since 1995, with a prostate biopsy recommended for men with PSA ≥2.5 ng/ml. The control group of 10 000 men not invited has been exposed to a previously reported increased rate of opportunistic PSA testing. Both groups were followed until December 31, 2012. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Observed cumulative PC incidence and mortality rates in both groups were calculated using the actuarial method. Using historical data from 1990-1994 (pre-PSA era), we calculated expected PC incidence and mortality rates in the absence of any PSA testing. The number needed to invite (NNI) and the number needed to diagnose (NND) were calculated by comparing the expected versus observed incidence and mortality rates. RESULTS AND LIMITATIONS: At 18 yr, 1396 men were diagnosed with PC and 79 men died of PC in the screening group, compared to 962 and 122, respectively, in the control group. In the screening group, the observed cumulative PC incidence/mortality was 16%/0.98% compared to expected values of 6.8%/1.7%. The corresponding values for the control group were 11%/1.5% and 6.9%/1.7%. Organized screening was associated with an absolute PC-specific mortality reduction of 0.72% (95% confidence interval [CI] 0.50-0.94%) and relative risk reduction of 42% (95% CI 28-54%). There was an absolute reduction in PC deaths of 0.20% (95% CI -0.06% to 0.47%) and a relative risk reduction of 12% (95% CI -5 to 26%) associated with opportunistic PSA testing. NNI and NND were 139 (95% CI 107-200) and 13 for organized biennial screening and 493 (95% CI 213- -1563) and 23 for opportunistic screening. The extent of opportunistic screening could not be measured; incidence trends were used as a proxy. CONCLUSIONS: Organized screening reduces PC mortality but is associated with overdiagnosis. Opportunistic PSA testing had little if any effect on PC mortality and resulted in more overdiagnosis, with almost twice the number of men needed to be diagnosed to save one man from dying from PC compared to men offered an organized biennial screening program. PATIENT SUMMARY: Prostate-specific antigen (PSA) screening within the framework of an organized program seems more effective than unorganized screening.