Population-based screening for prostate cancer by measuring free and total serum prostate-specific antigen in Sweden

Model-based screening for pancreatic cancer in Sweden

BACKGROUND

Detecting pancreatic cancer at an earlier stage may contribute to an increased survival. Patients with stage I pancreatic cancer have a 5-year survival rate of 36%, while stage IV patients have a 5-year survival rate of 1% in Sweden. Research into novel blood-based biomarkers for pancreatic cancer is highly intensive and innovative, but has yet to result in any routine screening test. The aim of this study was to evaluate the specificity and sensitivity of a hypothetical blood test for pancreatic cancer used for screening purposes and the economic aspects of testing.

METHOD

A model of a screening test was created, with varying specificity and sensitivity both set at 80%, 85%, 90%, 95% or 99% and applied to selected risk groups. Excessive costs of false positive screening outcomes, QALYs, ICERs and total costs were calculated.

RESULTS

Individuals with family history and genetic mutations associated with pancreatic cancer, new-onset diabetes ≥50 years of age and early symptoms had the highest positive predictive values and ICERs beneath the willingness-to-pay-level of EUR 100,000/QALY. Screening of the general population and smokers resulted in a high rate of false positive cases and extensive extra costs.

CONCLUSIONS

General screening for pancreatic cancer is not cost-effective, while screening of certain high-risk groups may be economically justified given the availability of a high-performing blood-based test.

GC-MS-based metabolomics reveals new biomarkers to assist the differentiation of prostate cancer and benign prostatic hyperplasia

Lack of efficient noninvasive biomarkers for differentiating prostate cancer (PCa) and benign prostate hyperplasia (BPH) is a serious concern for men's health worldwide. In this study, we aimed to improve the diagnostic capability of the existing noninvasive biomarkers for PCa. GC-MS-based untargeted metabolomics was employed to analyze plasma samples for 41 PCa patients and 38 BPH controls. Both univariate and multivariate statistical analyses were performed to screen for differential metabolites between PCa and BPH, followed by the selection of potential biomarkers through machine learning. The chosen candidate biomarkers were then verified by targeted analysis and transcriptome data. The results showed that twelve metabolites were significantly dysregulated between PCa and BPH, three metabolites including L-serine, myo-inositol, and decanoic acid could be potential biomarkers for discriminating PCa from BPH. Most importantly, ROC curve analysis demonstrated that the involvement of the three potential biomarkers has increased the area under the curve (AUC) value of cPSA and tPSA from 0.542 and 0.592 to 0.781, respectively. Therefore, it was concluded that the involvement of L-serine, myo-inositol, and decanoic acid can largely improve the diagnostic capability of the commonly used noninvasive biomarkers in the clinic for differentiating PCa from BPH.

Poor Follow-up After Elevated Prostate-specific Antigen Tests: A Population-based Cohort Study

BACKGROUND

Although prostate-specific antigen (PSA) testing is common, little is known about the pattern of retesting by either PSA values or subsequent prostate biopsies. Poor follow-up of high PSA values may lead to delayed diagnosis.

OBJECTIVE

To estimate the probabilities of follow-up (including retesting, prostate biopsies, diagnosis, and cause-specific death) for men undergoing prostate cancer testing at a population level.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study design for men living in Stockholm with no previous diagnosis of prostate cancer between 2003 and 2015. Men were linked to the national health and population registries in Sweden. We report follow-up for men aged 50-79 yr at 2003 or at their index PSA test.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

State probabilities with 95% confidence intervals (CIs) were calculated using multistate Markov models.

RESULTS AND LIMITATIONS

Among men not previously diagnosed with prostate cancer with an initial PSA value of ≥10ng/ml, the proportions at 1 yr with no subsequent testing or only elevated PSA test values >3ng/ml were 21.7% (95% CI: 19.5, 23.9), 25.2% (95% CI: 23.9, 26.6), and 47.7% (95% CI: 46.2, 49.1) for those aged 50-59, 60-69, and 70-79 yr, respectively. No significant changes were noticed when stratifying by comorbidities. Limitations include the lack of detail from patient medical charts. This detail would have allowed for more accurate assessment of appropriate clinical follow-up.

CONCLUSIONS

Regardless of medical history, a large proportion of men with PSA≥10ng/ml were not followed appropriately at 1 yr after the index PSA test. This may partially explain why opportunistic testing is not as effective as screening within trials to reduce prostate cancer mortality.

PATIENT SUMMARY

For men aged 50-69 yr, who undertake a prostate-specific antigen (PSA) test, a PSA level of >10ng/ml should prompt further investigation. However, we found that one out of 10 of these men did not receive repeat testing within 1 yr of the initial test. This may partially explain why opportunistic prostate cancer testing is less effective than screening trials.

Computer aided detection in prostate cancer diagnostics: A promising alternative to biopsy? A retrospective study from 104 lesions with histological ground truth

BACKGROUND

Prostate cancer (PCa) diagnosis by means of multiparametric magnetic resonance imaging (mpMRI) is a current challenge for the development of computer-aided detection (CAD) tools. An innovative CAD-software (Watson Elementary™) was proposed to achieve high sensitivity and specificity, as well as to allege a correlate to Gleason grade.

AIM/OBJECTIVE

To assess the performance of Watson Elementary™ in automated PCa diagnosis in our hospital´s database of MRI-guided prostate biopsies.

METHODS

The evaluation was retrospective for 104 lesions (47 PCa, 57 benign) from 79, 64.61±6.64 year old patients using 3T T2-weighted imaging, Apparent Diffusion Coefficient (ADC) maps and dynamic contrast enhancement series. Watson Elementary™ utilizes signal intensity, diffusion properties and kinetic profile to compute a proportional Gleason grade predictor, termed Malignancy Attention Index (MAI). The analysis focused on (i) the CAD sensitivity and specificity to classify suspect lesions and (ii) the MAI correlation with the histopathological ground truth.

RESULTS

The software revealed a sensitivity of 46.80% for PCa classification. The specificity for PCa was found to be 75.43% with a positive predictive value of 61.11%, a negative predictive value of 63.23% and a false discovery rate of 38.89%. CAD classified PCa and benign lesions with equal probability (P 0.06, χ2 test). Accordingly, receiver operating characteristic analysis suggests a poor predictive value for MAI with an area under curve of 0.65 (P 0.02), which is not superior to the performance of board certified observers. Moreover, MAI revealed no significant correlation with Gleason grade (P 0.60, Pearson´s correlation).

CONCLUSION

The tested CAD software for mpMRI analysis was a weak PCa biomarker in this dataset. Targeted prostate biopsy and histology remains the gold standard for prostate cancer diagnosis.

Characteristics of men responding to an invitation to undergo testing for prostate cancer as part of a randomised trial

BACKGROUND

Sociodemographic characteristics are associated with participating in cancer screening and trials. We compared the characteristics of those responding with those not responding to a single invitation for prostate-specific antigen (PSA) testing for prostate cancer as part of the Cluster randomised triAl of PSA testing for Prostate cancer (CAP).

METHODS

Age, rurality and deprivation among 197,763 men from 271 cluster-randomised primary care centres in the UK were compared between those responding (n = 90,300) and those not responding (n = 100,953) to a prostate cancer testing invitation.

RESULTS

There was little difference in age between responders and nonresponders. Responders were slightly more likely to come from urban rather than rural areas and were slightly less deprived than those who did not respond.

CONCLUSION

These data indicate similarities in age and only minor differences in deprivation and urban location between responders and nonresponders. These differences were smaller, but in the same direction as those observed in other screening trials.

TRIAL REGISTRATION

ISRCTN92187251 . Registered on 29 November 2004.

Experiences of Uncertainty in Men With an Elevated PSA

A significant proportion of men, ages 50 to 70 years, have, and continue to receive prostate specific antigen (PSA) tests to screen for prostate cancer (PCa). Approximately 70% of men with an elevated PSA level will not subsequently be diagnosed with PCa. Semistructured interviews were conducted with 13 men with an elevated PSA level who had not been diagnosed with PCa. Uncertainty was prominent in men's reactions to the PSA results, stemming from unanswered questions about the PSA test, PCa risk, and confusion about their management plan. Uncertainty was exacerbated or reduced depending on whether health care providers communicated in lay and empathetic ways, and provided opportunities for question asking. To manage uncertainty, men engaged in information and health care seeking, self-monitoring, and defensive cognition. Results inform strategies for meeting informational needs of men with an elevated PSA and confirm the primary importance of physician communication behavior for open information exchange and uncertainty reduction.

Rule-based versus probabilistic selection for active surveillance using three definitions of insignificant prostate cancer

PURPOSE

To study whether probabilistic selection by the use of a nomogram could improve patient selection for active surveillance (AS) compared to the various sets of rule-based AS inclusion criteria currently used.

METHODS

We studied Dutch and Swedish patients participating in the European Randomized study of Screening for Prostate Cancer (ERSPC). We explored which men who were initially diagnosed with cT1-2, Gleason 6 (Gleason pattern ≤3 + 3) had histopathological indolent PCa at RP [defined as pT2, Gleason pattern ≤3 and tumour volume (TV) ≤0.5 or TV ≤ 1.3 ml, and TV no part of criteria (NoTV)]. Rule-based selection was according to the Prostate cancer Research International: Active Surveillance (PRIAS), Klotz, and Johns Hopkins criteria. An existing nomogram to define probability-based selection for AS was refitted for the TV1.3 and NoTV indolent PCa definitions.

RESULTS

619 of 864 men undergoing RP had cT1-2, Gleason 6 disease at diagnosis and were analysed. Median follow-up was 8.9 years. 229 (37%), 356 (58%), and 410 (66%) fulfilled the TV0.5, TV1.3, and NoTV indolent PCa criteria at RP. Discriminating between indolent and significant disease according to area under the curve (AUC) was: TV0.5: 0.658 (PRIAS), 0.523 (Klotz), 0.642 (Hopkins), 0.685 (nomogram). TV1.3: 0.630 (PRIAS), 0.550 (Klotz), 0.615 (Hopkins), 0.646 (nomogram). NoTV: 0.603 (PRIAS), 0.530 (Klotz), 0.589 (Hopkins), 0.608 (nomogram).

CONCLUSIONS

The performance of a nomogram, the Johns Hopkins, and PRIAS rule-based criteria are comparable. Because the nomogram allows individual trade-offs, it could be a good alternative to rigid rule-based criteria.

Excess all-cause mortality in the evaluation of a screening trial to account for selective participation

OBJECTIVE

In addition to disease-specific mortality, a randomized controlled cancer screening trial may be evaluated in terms of excess mortality, in which case no patient-specific information on causes of death is needed. We studied the effect of not accounting for attendance on the calculated excess mortality in a prostate cancer screening trial.

METHODS

The numerator of the excess mortality rate related to prostate cancer diagnoses in each study arm equals the excess number of deaths observed in the cancer patients. The estimation of the expected number of deaths in the absence of the prostate cancer diagnoses has to account for the self-selection of those participating in the trial, particularly if the proportion of non-participants is substantial.

SETTING

The European prostate cancer screening trial (ERSPC).

RESULTS

In the screening arm, non-attendees had roughly twice the mortality rate of attendees. Approximately twice as many cancers were detected in the screening arm compared with the control arm, primarily in attendees. Unless attendance is properly accounted for, the expected mortality of prostate cancer patients in the screening arm is overestimated by 0.9-3.6 deaths per 1000 person-years.

CONCLUSIONS

Attendees have a lower all-cause mortality rate (are healthier) and a higher probability of a prostate cancer diagnosis than non-attendees and the men randomized to the control arm. If attendance is not accounted for, the excess mortality and the between-arm excess mortality rate ratio are underestimated and screening is considered more effective than it actually is. These effects may be sizeable, notably if non-attendance is common. Correcting for attendance status is important in the calculation of the excess mortality rate in prostate cancer patients that can be used in conjunction with a disease-specific mortality analysis in a randomized controlled cancer screening trial.

Efficacy versus effectiveness study design within the European screening trial for prostate cancer: consequences for cancer incidence, overall mortality and cancer-specific mortality

OBJECTIVE

To assess the impact of different study designs on outcome data within the European Randomized Study of Screening for Prostate Cancer (ERSPC).

METHODS

Observed data from the Gothenburg centre (effectiveness trial with upfront randomization before informed consent) and the Rotterdam centre (efficacy trial with randomization after informed consent) were compared with expected data, which were retrieved from national cancer registries and life tables. Endpoints were 11-year cumulative prostate cancer (PC) incidence, overall mortality and PC-specific mortality.

RESULTS

In Gothenburg, the 11-year PC incidence was higher than predicted (5.8%) in both the intervention (12.4%) and control arms (7.3%). The observed overall mortality was higher than predicted (15.9%) in both the intervention (17.8%) and control arms (18.5%). The observed PC-specific mortality in the intervention arm was 0.56% versus 0.83% in the control arm, while the expected mortality was 0.83%. In Rotterdam, the observed PC incidence in the intervention arm (10.4%) was higher than expected (4.4%). The incidence in the control arm was 4.6%. The observed overall mortality was lower than expected: 13.6% in the intervention arm and 14.0% in the control arm versus an expected mortality of 16.1%. The observed PC-specific mortality was lower than expected (0.65%) in both the intervention (0.27%) and control arms (0.41%).

CONCLUSIONS

Our results suggest that an efficacy trial with informed consent prior to randomization may have introduced a 'healthy screenee bias'. Therefore, an effectiveness trial with consent after randomization may more accurately estimate the PC-specific mortality reduction if population-based screening is introduced.

The implementation of screening for prostate cancer

The objective of this study was to determine whether screening for prostate cancer (PC) reduces PC mortality and, if so, whether the required criteria to be introduced as a population-based screening program are satisfied. A literature review was conducted through electronic scientific databases. The screening tests, that is, PSA and digital rectal examination, have limited sensitivity and specificity for detecting PC; screening produces a beneficial stage shift and reduces PC mortality. Nevertheless, PC screening causes a large increase in the cumulative incidence, and the understanding of the economic cost and quality-of-life parameters are limited. PC screening cannot be justified yet in the context of a public health policy.

Racial differences in PSA screening interval and stage at diagnosis

OBJECTIVES

This study examined PSA screening interval of black and white men aged 65 or older and its association with prostate cancer stage at diagnosis.

METHODS

SEER-Medicare data were examined for 18,067 black and white men diagnosed with prostate cancer between 1994 and 2002. Logistic regression was used to assess the association between race, PSA screening interval, and stage at diagnosis. Analysis also controlled for age, marital status, comorbidity, diagnosis year, geographic region, income, and receipt of surgery.

RESULTS

Compared to whites, blacks diagnosed with prostate cancer were more likely to have had a longer PSA screening interval prior to diagnosis, including a greater likelihood of no pre-diagnosis use of PSA screening. Controlling for PSA screening interval was associated with a reduction in blacks' relative odds of being diagnosed with advanced (stage III or IV) prostate cancer, to a point that the stage at diagnosis was not statistically different from that of whites (OR=1.12, 95% CI=0.98-1.29). Longer intra-PSA intervals were systematically associated with greater odds of diagnosis with advanced disease.

CONCLUSIONS

More frequent or systematic PSA screening may be a pathway to reducing racial differences in prostate cancer stage at diagnosis, and, by extension, mortality.

Is delayed radical prostatectomy in men with low-risk screen-detected prostate cancer associated with a higher risk of unfavorable outcomes?

BACKGROUND

Strategies of active surveillance (AS) of low-risk screen-detected prostate cancer have emerged, because the balance between survival outcomes and quality of life issues when radically treating these malignancies is disputable. Delay before radical treatment caused by active surveillance may be associated with an impaired chance of curability.

METHODS

Men diagnosed with low-risk (T1c/T2; prostate-specific antigen [PSA] = <10.0; PSA density, <0.2 ng/mL; Gleason score, 3 + 3=6; 1-2 positive biopsies) prostate cancer in the Swedish section of the European Randomized Study of Screening for Prostate Cancer who received radical prostatectomy (RP) were studied. One group received immediate RP, whereas another group received delayed RP after an initial period of expectant management. These groups were compared regarding histopathological and biochemical outcomes, correcting for baseline differences.

RESULTS

Mean follow-up after diagnosis was 5.7 years (standard deviation [SD], 3.2). The immediate RP group (n = 158) received RP a mean of 0.5 (SD, 0.2) years after diagnosis; the delayed RP group (n = 69) received RP after 2.6 (SD, 2.0) years (P < .001). After adjustment for small baseline dissimilarities, no differences in RP frequencies of Gleason score >6 (odds ratio [OR], 1.54; P = .221), capsular penetration (OR, 2.45; P = .091), positive margins (OR, 1.34; P = .445), RP tumor volume (difference, 0.099; P = .155), or biochemical progression rates (P = .185, P = .689) were found between groups, although all data were in favor of immediate RP.

CONCLUSIONS

With limited patient numbers available for analysis, differences in intermediate outcomes between immediate RP and delayed RP were nonsignificant. The delayed RP group may be subject to a selection bias. Prospective evaluation of active surveillance protocols is essential.

Anxiety associated with prostate cancer screening with special reference to men with a positive screening test (elevated PSA) - Results from a prospective, population-based, randomised study

Levels of anxiety were assessed through questionnaires completed by 1781 screen-positive (PSA > or = 3 ng/mL) men attending the European Randomised Study of Screening for Prostate Cancer in Gothenburg, Sweden. During the first visit (clinical examination, including biopsies), no anxiety whilst awaiting the PSA test results was reported by 66% and 2% reported high levels of anxiety. A multinomial logistics model for repeated measurements, adjusted for age, PSA level, heredity, biopsy finding and urinary symptoms, revealed that anxiety awaiting the PSA was only influenced (increased) by the existence of previously elevated PSA tests (p<.0001). No anxiety associated with biopsy was reported by 45%, while 6% experienced high levels of anxiety. Levels of anxiety decreased significantly with subsequent rounds of examinations (p<0.0001) and with increasing age (p=0.0016). Anxiety associated with prostate cancer screening in general is low to moderate, even in men with elevated PSA, and severe anxiety affects a smaller group of susceptible men.

Population-based screening for prostate cancer by measuring total serum prostate-specific antigen in Iran

OBJECTIVE

To report the results from an Iranian large population-based randomized study of screening using prostate-specific antigen (PSA) to detect prostate cancer.

MATERIALS AND METHODS

A total of 3758 Iranian men older than 40 years were mass checked by PSA-based screening. Men with an abnormal digital rectal examination (DRE) and serum total PSA level of greater than 4 ng/mL, underwent transrectal ultrasonography (TRUS)-guided extended prostate biopsy.

RESULTS

The PSA value (mean +/- standard deviation, SD) in all men without prostate cancer was 1.6 +/- 1.1 ng/mL and in those with cancer 18 +/- 44.8 ng/mL (P = 0.001). PSA values increased with age. In those aged 40-49, 50-59, 60-69 and > or = 70 years, the mean +/- SD PSA values were 1.3 +/- 0.7, 1.4 +/- 0.8, 1.8 +/- 1 and 2.2 +/- 1.6 ng/mL, respectively. Among the screened men, 323 (8.6%) had a serum PSA concentration greater than 4 ng/mL. Of patients who underwent prostate biopsy (230, 71.2%), 129 (positive predictive value, 56.1%) had prostate cancer. Additionally, nine cancers were detected among 16 patients with PSA of less than 4 ng/mL who had a doubtful DRE finding. The overall cancer detection rate was 3.6%; 1.4% at 40-49, 1.6% at 50-59, 4.2% at 60-69 and 12.9% at >/=70 years. Conventional systematic sextant biopsies, which accounted for six of the 10 cores in our biopsy scheme, detected 98 (71%) of the cancers.

CONCLUSIONS

The Iranian male population develops prostate cancer quite commonly if their serum PSA levels are greater than 4.0 ng/mL. In this study, 65.9% of the detected cancers were clinically significant. The conventional systematic sextant technique may be inappropriate for detection of all prostate cancers. The results need to be confirmed in other randomized trials.

PSA doubling time predicts the outcome after active surveillance in screening-detected prostate cancer: results from the European randomized study of screening for prostate cancer, Sweden section

This study reports the outcome of active surveillance in men with PSA screening-detected prostate cancer (PC), and PSA doubling time (PSADT) was evaluated as a predictor of selecting patients to active treatment or surveillance. On December 31, 1994, 10,000 men were randomized to biennial PSA testing. Through to December 2004, a total of 660 men were diagnosed with PC, of whom 270 managed with initial surveillance. Of these 270 patients, 104 (39%) received active treatment during follow-up, 70 radical prostatectomy, 24 radiation and 10 endocrine treatment. Those who received active treatment during follow-up (mean 63 months) were significantly younger (62.6 vs. 65.5 years, p < 0.0001) and had a shorter PSADT (3.7 vs. 12 years, p < 0.0001). PSA relapse was observed in 9 of 70 patients who received RRP during a mean follow-up of 37 months. Seven of these nine PSA relapses were in the patients with preoperative PSADT < 2 years. None of the 37 operated patients with a PSADT > 4 years had a PSA relapse. In a Cox regression analysis adjusted for PSA, ratio-free PSA and amount of cancer in biopsy, only the preoperative PSADT was statistically significant predictor of PSA relapse in p = 0.031. The optimal candidate for surveillance is a man with early, low-grade, low-stage PC and a PSADT > 4 years. In younger men with a PSADT of less than 4 years, surveillance does not seem to be a justified alternative, and patient should be informed about the risk with such an approach.

Reduction of prostate cancer mortality in Tyrol, Austria, after introduction of prostate-specific antigen testing

The objective of this study was to analyze in detail the time trend in prostate cancer mortality in the population of Tyrol, Austria. In Tyrol, prostate-specific antigen tests were introduced in 1988-1989 and, since 1993, have been offered to all men aged 45-74 years free of charge. More than three quarters of all men in this age group had at least one such test in the last decade. The authors applied the age-period-cohort model by Poisson regression to mortality data covering more than three decades, from 1970 to 2003. For Tyrol, the full model with age and period and cohort terms fit fairly well. Period terms showed a significant reduction in prostate cancer mortality in the last 5 years, with a risk ratio of 0.81 (95% confidence interval: 0.68, 0.98) for Tyrol; for Austria without Tyrol, no effect was seen, with a risk ratio of 1.00 (95% confidence interval: 0.95, 1.05). Each was compared with the mortality rate in the period 1989-1993. Although the results of randomized screening trials are not expected until 2008-2010, these findings support the evidence that prostate-specific antigen testing offered to a population free of charge can reduce prostate cancer mortality.

Population-based screening for prostate cancer by measuring free and total serum prostate-specific antigen in Iran

PURPOSE

To evaluate the natural background of prostate cancer in Iran a large population-based study of screening using total prostate-specific antigen (tPSA) and per cent free PSA (fPSA) as the initial test was performed.

MATERIALS AND METHODS

For 9 years (1996 to 2004) in Tehran, Iran, 3670 Iranian men older than 40 years were mass checked by PSA-based screening. They were invited to have a digital rectal examination (DRE), serum PSA assay and transrectal ultrasonography (TRUS)-guided sextant prostate biopsy to see if the DRE was clinically suspicious of malignancy, the serum PSA was > or =2.1 ng/ml or free-to-total PSA (f/tPSA) ratio < or=15%.

RESULTS

In 433 (11.8%) of screened males, tPSA levels exceeded the cut-off value of > or =2.1 ng/ml and 128 prostate cancers were diagnosed [positive predictive value (PPV) 29.6%] corresponding to an overall detection rate of 3.5%. Altogether 138 cancers were detected (detection rate 3.8%); none were stage M(1), three were stage N(+) and 4 stage T(3). A threshold tPSA of > or =2.1 ng/ml would have detected 128 cancers in 447 biopsied men (PPV 29%). There were 109 of 138 (79%) men with cancer who had an f/tPSA of < or =15%, while 152 of 305 (49.8%) with benign biopsies had a f/tPSA of < or =15%, which corresponds to a PPV of 30.8%.

CONCLUSION

PSA-based screening with low PSA cut-off values increase the detection rate of clinically significant, organ confined and potentially curable prostate cancer. Further studies are warranted in order to determine the incidence and prevalence of prostate cancer in different ethnic groups.

The feasibility and results of a population-based approach to evaluating prostate-specific antigen screening for prostate cancer in men with a raised familial risk

The feasibility of a population-based evaluation of screening for prostate cancer in men with a raised familial risk was investigated by studying reasons for non-participation and uptake rates according to postal recruitment and clinic contact. The levels of prostate-specific antigen (PSA) and the positive predictive values (PPV) for cancer in men referred with a raised PSA and in those biopsied were analysed. First-degree male relatives (FDRs) were identified through index cases (ICs): patients living in two regions of England and diagnosed with prostate cancer at age ⩽65 years from 1998 to 2004. First-degree relatives were eligible if they were aged 45–69 years, living in the UK and had no prior diagnosis of prostate cancer. Postal recruitment was low (45 of 1687 ICs agreed to their FDR being contacted: 2.7%) but this was partly due to ICs not having eligible FDRs. A third of ICs in clinic had eligible FDRs and 49% (192 out of 389) agreed to their FDR(s) being contacted. Of 220 eligible FDRs who initially consented, 170 (77.3%) had a new PSA test taken and 32 (14.5%) provided a previous PSA result. Among the 170 PSA tests, 10% (17) were ⩾4 ng ml⁻¹ and 13.5% (23) tests above the age-related cutoffs. In 21 men referred, five were diagnosed with prostate cancer (PPV 24%; 95% CI 8, 47). To study further the effects of screening, patients with a raised familial risk should be counselled in clinic about screening of relatives and data routinely recorded so that the effects of screening on high-risk groups can be studied.

Reproducibility and Accuracy of Measurements of Free and Total Prostate-Specific Antigen in Serum vs Plasma after Long-Term Storage at −20 °C

Background: Long-term frozen storage may alter the results of prostate-specific antigen (PSA) measurements, mainly because of degradation of free PSA (fPSA) in vitro. We compared the effects of long-term storage on fPSA, total PSA (tPSA), and complexed PSA (cPSA) in serum vs EDTA-plasma samples.

Methods: We measured fPSA and tPSA concentrations in matched pairs of archival serum and EDTA-plasma samples (stored frozen at −20 °C for 20 years) from a large population-based cohort in Malmö, Sweden. We also compared concentrations in age-matched men with those in samples not subjected to long-term storage, obtained from participants in a population-based study of prostate cancer screening in Göteborg, Sweden. These contemporary samples were handled according to standardized preanalytical and analytical protocols aimed at minimizing in vitro degradation. tPSA and fPSA measurements were performed with a commercial assay (Prostatus Dual Assay; Perkin-Elmer Life Sciences).

Results: Concentrations of tPSA and fPSA and calculated cPSA (tPSA − fPSA) in archival plasma were not significantly different from those in contemporary serum from age-matched men. In archival serum, however, random variability of fPSA was higher vs plasma than in contemporary samples, whereas systematic error of fPSA analyses was similarly small in archival and contemporary serum and plasma.

Conclusions: Concentrations of tPSA and calculated cPSA were highly stable in plasma and serum samples subjected to long-term storage at −20 °C. Greater random variability, rather than a systematic decrease, may explain differences in fPSA analyses observed in archival serum.

Prognostic value of serum markers for prostate cancer

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Behandlungsfehler im Zusammenhang mit der Bestimmung des prostataspezifischen Antigens

Advances in prostate specific antigen (PSA) diagnosis are accompanied by deficits in realization. The justification of claims by affected patients against their doctors are reviewed by commissions of experts and mediation by medical councils out of court, impartial and free of charge. The objectivity of the review is ensured by the independence of the commission and its members as well as the determination of facts and their assessment. Criteria are professional standards and required care. Since 1995, 21 requests by affected patients have been reviewed. In 15 cases (71.4%), treatment errors were ascertained. This involved either a delayed or an insufficient diagnosis (prostatic biopsy). In ten of the patients, a mostly early prostate cancer would have be diagnosed and treated at the time of the first finding of PSA values between 3.3 and 10.4 ng/ml. In ten of 13 patients, the tumor was diagnosed late, having PSA values between 6.8 and 1251 ng/ml with no chance of curative therapy. As in other life threatening diseases, time of recognition is most important for the diagnosis and treatment of patients with prostate cancer. Particularly for early recognition, PSA is much more sensitive then digital rectal examination, and in cases without a digital finding is the only parameter for early diagnoses. In men with suspicious PSA values (>4.0 ng/ml) suitable a diagnostic test (prostate biopsy) is required early, until cancer is detected or excluded.

Screening for prostate cancer

Epidemiologically, prostate cancer is the most common cancer in the Western world after skin cancer. To date, it is still unknown whether screening for prostate cancer is justified, because results of randomised clinical trials are not yet available. The available screening tests (i.e. prostate-specific antigen (PSA) test) do not always detect cancers that otherwise would have resulted in prostate cancer mortality. Favourable results from prostate cancer screening include an increasing number of men with localised disease and an increase in the number of well-differentiated tumours. However, the risk of overdiagnosis and subsequent over-treatment (due to the diagnosis of localised disease), using aggressive therapies fuels arguments against screening. Therefore, until more evidence is available proving otherwise, prostate cancer screening can only be justified in the context of clinical trials.