Assessment of causes of death in a prostate cancer screening trial

Screening history and risk of death from prostate cancer: a nested case-control study within the screening arm of the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC)

PURPOSE

We assessed the risk of death from prostate cancer (PCa) in relation to men's screening histories, i.e., screening attendance among men who were offered screening.

METHODS

Men in the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) screening arm were invited to up to three screening rounds with the serum prostate-specific antigen (PSA) test at 4-year intervals during 1996-2007. Case subjects (n = 330) were men who died from PCa. Each case was matched to five controls (n = 1544) among the men who were free of PCa. Screening history was defined as (1) never/ever attended screening prior to the case diagnosis; (2) attended at the first screening round; and (3) recency of screening, calculated as the time from last screening attendance to the date of case diagnosis. The association between screening history and the risk of death from PCa was estimated by odds ratios (OR) with 95% confidence intervals (CI) using conditional logistic regression.

RESULTS

Having ever attended screening versus never attended was associated with a reduced risk of PCa death (OR 0.60, 95% CI 0.45-0.81) and a similar association was found for those attended (versus not attended) the first screening round (OR 0.67, 95% CI 0.51-0.87). The effect by time since last screen for the risk of PCa death was significantly lower 2-7 years since last screen.

CONCLUSION

Among men invited to screening, subjects who attended any PSA screening during the previous 19 years had a 40% reduction in PCa mortality compared to non-screened men.

Early detection of clinically significant prostate cancer: protocol summary and statistical analysis plan for the ProScreen randomised trial

INTRODUCTION

Evidence on the effectiveness of prostate cancer screening based on prostate-specific antigen is inconclusive and suggests a questionable balance between benefits and harms due to overdiagnosis, and complications from biopsies and overtreatment. However, diagnostic accuracy studies have shown that detection of clinically insignificant prostate cancer can be reduced by MRI combined with targeted biopsies.The aim of the paper is to describe the analysis of the ProScreen randomised trial to assess the performance of the novel screening algorithm in terms of the primary outcome, prostate cancer mortality and secondary outcomes as intermediate indicators of screening benefits and harms of screening.

METHODS

The trial aims to recruit at least 111 000 men to achieve sufficient statistical power for the primary outcome. Men will be allocated in a 1:3 ratio to the screening and control arms. Interim analysis is planned at 10 years of follow-up, and the final analysis at 15 years. Difference between the trial arms in prostate cancer mortality will be assessed by Gray's test using intention-to-screen analysis of randomised men. Secondary outcomes will be the incidence of prostate cancer by disease aggressiveness, progression to advanced prostate cancer, death due to any cause and cost-effectiveness of screening.

ETHICS AND DISSEMINATION

The trial protocol was reviewed by the ethical committee of the Helsinki University Hospital (2910/2017). Results will be disseminated through publications in international peer-reviewed journals and at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03423303.

Testosterone replacement therapy is not associated with increased prostate cancer incidence, prostate cancer-specific, or cardiovascular disease-specific mortality in Finnish men

BACKGROUND

Concerns have been expressed over the safety of testosterone replacement therapy (TRT) in men with late-onset hypogonadism (LOH). Previous studies have shown controversial results regarding the association of TRT with the risk of cardiovascular events or prostate cancer (PCa) incidence, aggressiveness, and mortality. This study explores the overall risk of PCa and risk by tumor grade and stage, as well as mortality from PCa and cardiovascular disease (CVD), among men treated with TRT compared to men without LOH and TRT use.

MATERIALS AND METHODS

The study included 78,615 men of age 55-67 years at baseline from the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). Follow-up started at randomization and ended at death, emigration, or a common closing date January 1st, 2017. Cox proportional hazards regression model with time-dependent variables and adjustment for age, trial arm, use of other medications, and Charlson comorbidity index was used. Comprehensive information on TRT purchases during 1995-2015 was obtained from the Finnish National Prescription Database. PCa cases were identified from the Finnish Cancer Registry and causes of death obtained from Statistics Finland.

RESULTS

Over the course of 18 years of follow-up, 2919 men were on TRT, and 285 PCa cases were diagnosed among them. TRT users did not exhibit a higher incidence or mortality rate of PCa compared to non-users. On the contrary, men using TRT had lower PCa mortality than non-users (HR = 0.52; 95% CI 0.3-0.91). Additionally, TRT users had slightly lower CVD and all-cause mortality compared to non-users (HR = 0.87; 95% CI 0.75-1.01 and HR = 0.93; 95% CI 0.87-1.0, respectively). No time- or dose-dependency of TRT use was evident in any of the analyses.

CONCLUSION

Men using TRT were not associated to increased risk for PCa and did not experience increased PCa- or CVD-specific mortality compared to non-users. Further studies considering blood testosterone levels are warranted.

Evidence of cancer progression as the cause of death in men with prostate cancer in Sweden

OBJECTIVE

To assess the strength of the evidence indicative of prostate cancer (PCa) progression as the adjudicated cause of death, according to age at death and PCa risk category.

PATIENTS AND METHODS

Using data from the Prostate Cancer data Base Sweden, we identified a study frame of 5543 men with PCa registered as the cause of death according to the Cause of Death Register. We assessed the evidence of PCa progression through a review of healthcare records for a stratified sample of 495/5543. We extracted data on prostate-specific antigen levels, presence of metastases on imaging, and PCa treatments, and quantified the evidence of disease progression using a points system.

RESULTS

Both no evidence and moderate evidence for PCa progression was more common in men aged >85 years at death than those aged <85 years (29% vs 14%). Among the latter, the proportion with no evidence or moderate evidence for PCa progression was 21% for low-risk, 14% for intermediate-risk, 8% for high-risk, and 0% for metastatic PCa. In contrast, in men aged >85 years, there was little difference in the proportion with no evidence or moderate evidence of PCa progression between PCa risk categories; 31% for low-risk, 29% for intermediate-risk, 29% for high-risk, and 21% for metastatic PCa. Of the 5543 men who died from PCa, 13% (95% confidence interval 5-19%) were estimated to have either no evidence or moderate evidence of PCa progression.

CONCLUSIONS

Weak evidence for PCa progression as cause of death was more common in older men with PCa and in those with low-risk PCa. This has implications for interpretation of mortality statistics especially when assessing screening and early treatment of PCa because the beneficial effect of earlier diagnosis could be masked by erroneous adjudication of PCa as cause of death in older men, particular those with localised disease at diagnosis.

Intervention-related Deaths in the European Randomized Study of Screening for Prostate Cancer

Background

Identification of intervention-related deaths is important for an accurate assessment of the ratio of benefit to harm in screening trials.

Objective

To investigate intervention-related deaths by study arm in the European Randomized Study of Prostate Cancer Screening (ERSPC).

Design, setting, and participants

ERSPC is a multicenter trial initiated in the 1990s to investigate whether screening on the basis of prostate-specific antigen (PSA) can decrease prostate cancer mortality. The present study included men in the core age group (55–69 yr: screening group n = 112 553, control group n = 128 681) with 16-yr follow-up.

Outcome measurements and statistical analysis

Causes of death among men with prostate cancer in ERSPC were predominantly evaluated by independent national committees via review of medical records according to a predefined algorithm. Intervention-related deaths were defined as deaths caused by complications during the screening procedure, treatment, or follow-up. Descriptive statistics were used for the results.

Results and limitations

In total, 34 deaths were determined to be intervention-related, of which 21 were in the screening arm and 13 in the control arm. The overall risk of intervention-related death was 1.41 (95% confidence interval 0.99–1.99) per 10 000 randomized men for both arms combined and varied among centers from 0 to 7.0 per 10 000 randomized men. A limitation of this study is that differences in procedures among centers decreased the comparability of the results.

Conclusions

Intervention-related deaths were rare in ERSPC. Monitoring of intervention-related deaths in screening trials is important for assessment of harms.

Patient summary

We investigated deaths due to screening or treatment to assess harm in a trial of prostate cancer screening. Few such deaths were identified.

Antidiabetic Drugs and Prostate Cancer Prognosis in a Finnish Population-Based Cohort

BACKGROUND

Hyperinsulemia and glycemic control may play a role as prostate cancer prognostic factors, whereas use of certain antidiabetic drugs, that is metformin, could improve the prognosis. We examined the link between antidiabetic medication use and prostate cancer survival taking into account simultaneous use of multiple drugs.

METHODS

The study cohort composed of 6,537 men in The Finnish Randomized Study of Screening for Prostate Cancer with prostate cancer diagnosed 1996 to 2009. Use of medication was attained from the nationwide prescription database of the Social Insurance Institution of Finland. Median follow-up was 9.2 years postdiagnosis. A total of 1,603 (24,5%) men had used antidiabetic medication. A total of 771 men died of prostate cancer during the follow-up. We used multivariable-adjusted Cox regression to evaluate the risk of prostate cancer death and onset of androgen deprivation therapy (ADT) with adjustment for prostate cancer clinical characteristics, comorbidities and use of other drugs. Separate analyses were further adjusted for blood glucose.

RESULTS

Risk of prostate cancer death was higher among antidiabetic drug users overall (HR = 1.42; 95% CI, 1.18-1.70) compared with nonusers, separately among insulin and metformin users. Adjustment for blood glucose level abolished the risk increase. Risk of ADT initiation was increased among the medication users (HR = 1.26; 95% CI, 1.05-1.49).

CONCLUSIONS

Men with prostate cancer using antidiabetic medication are generally at increased risk of dying from prostate cancer compared with nonusers. The risk association is driven by underlying diabetes, as adjustment for blood glucose level ameliorates the risk increase.

IMPACT

Type 2 diabetes should be considered as a risk factor when considering prostate cancer prognosis.

Completeness and accuracy of national cancer and death registration for outcome ascertainment in trials-an ovarian cancer exemplar

BACKGROUND

There is a trend to increasing use of routinely collected health data to ascertain outcome measures in trials. We report on the completeness and accuracy of national ovarian cancer and death registration in the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS).

METHODS

Of the 202,638 participants, 202,632 were successfully linked and followed through national cancer and death registries of Northern Ireland, Wales and England. Women with registrations of any of 19 pre-defined ICD-10 codes suggestive of tubo-ovarian cancer or notification of ovarian/tubal/peritoneal cancer from hospital episode statistics or trial sites were identified. Copies of hospital and primary care notes were retrieved and reviewed by an independent outcomes review committee. National registration of site and cause of death as ovarian/tubal/peritoneal cancer (C56/C57/C48) obtained up to 3 months after trial censorship was compared to that assigned by outcomes review (reference standard).

RESULTS

Outcome review was undertaken in 3110 women on whom notification was received between 2001 and 2014. Ovarian cancer was confirmed in 1324 of whom 1125 had a relevant cancer registration. Sensitivity and specificity of ovarian/tubal/peritoneal cancer registration were 85.0% (1125/1324; 95% CI 83.7-86.2%) and 94.0% (1679/1786; 95% CI 93.2-94.8%), respectively. Of 2041 death registrations reviewed, 681 were confirmed to have a tubo-ovarian cancer of whom 605 had relevant death registration. Sensitivity and specificity were 88.8% (605/681; 95% CI 86.4-91.2%) and 96.7% (1482/1533, 95% CI 95.8-97.6%), respectively. When multiple electronic health record sources were considered, sensitivity for cancer site increased to 91.1% (1206/1324, 95% CI 89.4-92.5%) and for cause of death 94.0% (640/681, 95% CI 91.9-95.5%). Of 1232 with cancer registration, 8.7% (107/1232) were wrongly designated as ovarian/tubal/peritoneal cancers by the registry and 4.0% (47/1172) of confirmed tubo-ovarian cancers were mis-registered. In 656 with death registrations, 7.8% (51/656) were wrongly assigned as due to ovarian/tubal/peritoneal cancers while 6.2% (40/645) of confirmed tubo-ovarian cancer deaths were mis-registered.

CONCLUSION

Follow-up of trial participants for tubo-ovarian cancer using national registry data will result in incomplete ascertainment, particularly of the site due in part to the latency of registration. This can be reduced by using other routinely collected data such as hospital episode statistics. Central adjudication by experts though resource intensive adds value by improving the accuracy of diagnoses.

TRIAL REGISTRATION

ISRCTN: ISRCTN22488978 . Registered on 6 April 2000.

Antihypertensive drug use and prostate cancer-specific mortality in Finnish men

The aim of this study was to investigate pre- and post-diagnostic use of antihypertensive drugs on prostate cancer (PCa)-specific survival and the initiation of androgen deprivation therapy (ADT). The cohort investigated 8,253 PCa patients with 837 PCa-specific deaths during the median follow-up of 7.6 years after diagnosis. Information on drug use, cancer incidence, clinical features of PCa, and causes of death was collected from Finnish registries. Hazard ratios with 95% confidence intervals were calculated using Cox regression with antihypertensive drug use as a time-dependent variable. Separate analyses were performed on PCa survival related to pre- and post-diagnostic use of drugs and on the initiation of ADT. Antihypertensive drug use overall was associated with an increased risk of PCa-specific death (Pre-PCa: 1.21 (1.04–1.4), Post-PCa: 1.2 (1.02–1.41)). With respect to the separate drug groups, angiotensin II type 1 receptor (ATr) blockers, were associated with improved survival (Post-PCa: 0.81 (0.67–0.99)) and diuretics with an increased risk (Post-PCa: 1.25 (1.05–1.49)). The risk of ADT initiation was slightly higher among antihypertensive drug users as compared to non-users. In conclusion, this study supports anti-cancer effect of ATr blockers on PCa prognosis and this should be investigated further in controlled clinical trials.

Errors in determination of net survival: cause-specific and relative survival settings

BACKGROUND

Cause-specific and relative survival estimates differ. We aimed to examine these differences in common cancers where by possible identifying the most plausible sources of error in each estimate.

METHODS

Ten-year cause-specific and relative survival were estimated for lung, breast, prostate, ovary, oesophagus and colorectal cancers. The cause-specific survival was corrected for misclassification of cause of death. The Pohar-Perme relative survival estimator was modified by (1) correcting for differences in deaths from ischaemic heart disease (IHD) between cancers and general population; or (2) correcting the population hazard for smoking (lung cancer only).

RESULTS

For all cancers except breast and prostate, relative survival was lower than cause-specific. Correction for published error rates in cause of death gave implausible results. Correction for rates of IHD death gave slightly different relative survival estimates for lung, oesophagus and colorectal cancers. For lung cancer, when the population hazard was inflated for smoking, survival estimates were increased.

CONCLUSION

Results agreed with the consensus that relative survival is usually preferable. However, for some cancers, relative survival might be inaccurate (e.g. lung and prostate). Likely solutions include enhancing life tables to include other demographic variables than age and sex, and to stratify relative survival calculation by cause of death.

Could Differences in Treatment Between Trial Arms Explain the Reduction in Prostate Cancer Mortality in the European Randomized Study of Screening for Prostate Cancer?

BACKGROUND

Differential treatment between trial arms has been suggested to bias prostate cancer (PC) mortality in the European Randomized Study of Screening for Prostate Cancer (ERSPC).

OBJECTIVE

To quantify the contribution of treatment differences to the observed PC mortality reduction between the screening arm (SA) and the control arm (CA).

DESIGN, SETTING, AND PARTICIPANTS

A total of 14 136 men with PC (SA: 7310; CA: 6826) in the core age group (55-69yr) at 16yr of follow-up.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The outcomes measurements were observed and estimated numbers of PC deaths by treatment allocation in the SA and CA, respectively. Primary treatment allocation was modeled using multinomial logistic regression adjusting for center, age, year, prostate-specific antigen, grade group, and tumor-node-metastasis stage. For each treatment, logistic regression models were fitted for risk of PC death, separately for the SA and CA, and using the same covariates as for the treatment allocation model. Treatment probabilities were multiplied by estimated PC death risks for each treatment based on one arm, and then summed and compared with the observed number of deaths.

RESULTS AND LIMITATIONS

The difference between the observed and estimated treatment distributions (hormonal therapy, radical prostatectomy, radiotherapy, and active surveillance/watchful waiting) in the two arms ranged from -3.3% to 3.3%. These figures, which represent the part of the treatment differences between arms that cannot be explained by clinicopathological differences, are small compared with the observed differences between arms that ranged between 7.2% and 10.1%. The difference between the observed and estimated numbers of PC deaths among men with PC was 0.05% (95% confidence interval [CI] -0.1%, 0.2%) when applying the CA model to the SA, had the two groups received identical primary treatment, given their clinical characteristics. When instead applying the SA model to the CA, the difference was, as expected, very similar-0.01% (95% CI -0.3%, 0.2%). Consistency of the results of the models demonstrates the robustness of the modeling approach. As the observed difference between trial arms was 4.2%, our findings suggest that differential treatment explains only a trivial proportion of the main findings of ERSPC. A limitation of the study is that only data on primary treatment were available.

CONCLUSIONS

Use of prostate-specific antigen remains the predominant explanation for the reduction in PC mortality seen in the ERSPC trial and is not attributable to differential treatment between trial arms.

PATIENT SUMMARY

This study shows that prostate cancer deaths in the European screening trial (European Randomized Study of Screening for Prostate Cancer) were prevented because men were diagnosed and treated earlier through prostate-specific antigen screening, and not because of different, or better, treatment in the screening arm compared with the control arm.

A 16-yr Follow-up of the European Randomized study of Screening for Prostate Cancer

BACKGROUND

The European Randomized study of Screening for Prostate Cancer (ERSPC) has previously demonstrated that prostate-specific antigen (PSA) screening decreases prostate cancer (PCa) mortality.

OBJECTIVE

To determine whether PSA screening decreases PCa mortality for up to 16yr and to assess results following adjustment for nonparticipation and the number of screening rounds attended.

DESIGN, SETTING, AND PARTICIPANTS

This multicentre population-based randomised screening trial was conducted in eight European countries. Report includes 182160 men, followed up until 2014 (maximum of 16yr), with a predefined core age group of 162389 men (55-69yr), selected from population registry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The outcome was PCa mortality, also assessed with adjustment for nonparticipation and the number of screening rounds attended.

RESULTS AND LIMITATIONS

The rate ratio of PCa mortality was 0.80 (95% confidence interval [CI] 0.72-0.89, p<0.001) at 16yr. The difference in absolute PCa mortality increased from 0.14% at 13yr to 0.18% at 16yr. The number of men needed to be invited for screening to prevent one PCa death was 570 at 16yr compared with 742 at 13yr. The number needed to diagnose was reduced to 18 from 26 at 13yr. Men with PCa detected during the first round had a higher prevalence of PSA >20ng/ml (9.9% compared with 4.1% in the second round, p<0.001) and higher PCa mortality (hazard ratio=1.86, p<0.001) than those detected subsequently.

CONCLUSIONS

Findings corroborate earlier results that PSA screening significantly reduces PCa mortality, showing larger absolute benefit with longer follow-up and a reduction in excess incidence. Repeated screening may be important to reduce PCa mortality on a population level.

PATIENT SUMMARY

In this report, we looked at the outcomes from prostate cancer in a large European population. We found that repeated screening reduces the risk of dying from prostate cancer.

Cancer mortality does not differ by antiarrhythmic drug use: A population-based cohort of Finnish men

In-vitro studies have suggested that the antiarrhythmic drug digoxin might restrain the growth of cancer cells by inhibiting Na+/K+-ATPase. We evaluated the association between cancer mortality and digoxin, sotalol and general antiarrhythmic drug use in a retrospective cohort study. The study population consists of 78,615 men originally identified for the Finnish Randomized Study of Screening for Prostate Cancer. Information on antiarrhythmic drug purchases was collected from the national prescription database. We used the Cox regression method to analyze separately overall cancer mortality and mortality from the most common types of cancer. During the median follow-up of 17.0 years after the baseline 28,936 (36.8%) men died, of these 8,889 due to cancer. 9,023 men (11.5%) had used antiarrhythmic drugs. Overall cancer mortality was elevated among antiarrhythmic drug users compared to non-users (HR 1.43, 95% CI 1.34–1.53). Similar results were observed separately for digoxin and for sotalol. However, the risk associations disappeared in long-term use and were modified by background co-morbidities. All in all, cancer mortality was elevated among antiarrhythmic drug users. This association is probably non-causal as it was related to short-term use and disappeared in long-term use. Our results do not support the anticancer effects of digoxin or any other antiarrhythmic drug.

Costs of screening for prostate cancer: Evidence from the Finnish Randomised Study of Screening for Prostate Cancer after 20-year follow-up using register data

OBJECTIVES

Few empirical analyses of the impact of organised prostate cancer (PCa) screening on healthcare costs exist, despite cost-related information often being considered as a prerequisite to informed screening decisions. Therefore, we estimate the differences in register-based costs of publicly funded healthcare in the two arms of the Finnish Randomised Study of Screening for Prostate Cancer (FinRSPC) after 20 years.

METHODS

We obtained individual-level register data on prescription medications, as well as inpatient and outpatient care, to estimate healthcare costs for 80,149 men during the first 20 years of the FinRSPC. We compared healthcare costs for the men in each trial arm and performed statistical analysis.

RESULTS

For all men diagnosed with PCa during the 20-year observation period, mean PCa-related costs appeared to be around 10% lower in the screening arm (SA). Mean all-cause healthcare costs for these men were also lower in the SA, but differences were smaller than for PCa-related costs alone, and no longer statistically significant. For men dying from PCa, although the difference was not statistically significant, mean all-cause healthcare costs were around 10% higher. When analysis included all observations, cumulative costs were slightly higher in the CA; however, after excluding extreme values, cumulative costs were slightly higher in the SA.

CONCLUSIONS

No major cost impacts due to screening were apparent, but the FinRSPC's 20-year follow-up period is too short to provide definitive evidence at this stage. Longer term follow-up will be required to be better informed about the costs of, or savings from, introducing mass PCa screening.

A randomized trial of early detection of clinically significant prostate cancer (ProScreen): study design and rationale

The current evidence of PSA-based prostate cancer screening shows a reduction in cause-specific mortality, but with substantial overdiagnosis. Recently, new developments in detection of clinically relevant prostate cancer include multiple kallikreins as biomarkers besides PSA, and multiparametric magnetic resonance imaging (mpMRI) for biopsy decision. They offer opportunities for improving the outcomes in screening, particularly reduction in overdiagnosis and higher specificity for potentially lethal cancer. A population-based randomized screening trial will be started, with 67,000 men aged 55-67 years at entry. A quarter of the men will be allocated to the intervention arm, and invited to screening. The control arm will receive no intervention. All men in the screening arm will be offered a serum PSA determination. Those with PSA of 3 ng/ml or higher will have an additional multi-kallikrein panel and those with indications of increased risk of clinically relevant prostate cancer will undergo mpMRI. Men with a malignancy-suspect finding in MRI are referred to targeted biopsies. Screening interval is 6 years for men with baseline PSA < 1.5 ng/ml, 4 years with PSA 1.5-3.0 and 2 years if initial PSA > 3. The main outcome of the trial is prostate cancer mortality, with analysis at 10 and 15 years. The statistical power is sufficient for detecting a 28% reduction at 10 years and 22% at 15 years. The proposed study has the potential to provide the evidence to justify screening as a public health policy if mortality benefit can be sustained with substantially reduced overdiagnosis.

Impact of cause of death adjudication on the results of the European prostate cancer screening trial

BACKGROUND

The European Randomised Study of Prostate Cancer Screening has shown a 21% relative reduction in prostate cancer mortality at 13 years. The causes of death can be misattributed, particularly in elderly men with multiple comorbidities, and therefore accurate assessment of the underlying cause of death is crucial for valid results. To address potential unreliability of end-point assessment, and its possible impact on mortality results, we analysed the study outcome adjudication data in six countries.

METHODS

Latent class statistical models were formulated to compare the accuracy of individual adjudicators, and to assess whether accuracy differed between the trial arms. We used the model to assess whether correcting for adjudication inaccuracies might modify the study results.

RESULTS

There was some heterogeneity in adjudication accuracy of causes of death, but no consistent differential accuracy by trial arm. Correcting the estimated screening effect for misclassification did not alter the estimated mortality effect of screening.

CONCLUSIONS

Our findings were consistent with earlier reports on the European screening trial. Observer variation, while demonstrably present, is unlikely to have materially biased the main study results. A bias in assigning causes of death that might have explained the mortality reduction by screening can be effectively ruled out.

Prostate Cancer and Socioeconomic Status in the Finnish Randomized Study of Screening for Prostate Cancer

Prostate cancer (PC) screening remains controversial. We investigated whether screening reduces the difference in prostate cancer risk by socioeconomic status (SES). In 1996-2011, a total of 72,139 men from the Finnish Randomized Study of Screening for Prostate Cancer were analyzed. Outcome measures were PC incidence, mortality, and participation in screening. SES indicators were educational level, income, and home ownership status (data obtained from the Statistics Finland registry). The mean duration of follow-up was 12.7 years. Higher SES was associated with a higher incidence of low- to moderate-risk PC but with a lower risk of advanced PC. Higher education was associated with significantly lower PC mortality in both control and screening arms (risk ratio = 0.48-0.69; P < 0.05). Higher income was also associated with lower PC mortality but only in the control arm (risk ratio = 0.45-0.73; P < 0.05). There were no significant differences in SES gradient by arm (Pinteraction = 0.33 and Pinteraction = 0.47 for primary vs. secondary education and primary vs. tertiary education, respectively; Pinteraction = 0.65 and Pinteraction = 0.09 for low vs. intermediate income and low vs. high income, respectively; and Pinteraction = 0.27 among home ownership status strata). Substantial gradients by SES in PC incidence and mortality were observed in the control arm. Higher SES was associated with overdiagnosis of low-risk PC and, conversely, lower risk of incurable PC and lower PC mortality. Special attention should be directed toward recruiting men with low SES to participate in population-based cancer screening.

Digoxin and prostate cancer survival in the Finnish Randomized Study of Screening for Prostate Cancer

BACKGROUND

Protective effects have been suggested for digoxin against prostate cancer risk. However, few studies have evaluated the possible effects on prostate cancer-specific survival. We studied the association between use of digoxin or beta-blocker sotalol and prostate cancer-specific survival as compared with users of other antiarrhythmic drugs in a retrospective cohort study.

METHODS

Our study population consisted of 6537 prostate cancer cases from the Finnish Randomized Study of Screening for Prostate Cancer diagnosed during 1996-2009 (485 digoxin users). The median exposure for digoxin was 480 DDDs (interquartile range 100-1400 DDDs). During a median follow-up of 7.5 years after diagnosis, 617 men (48 digoxin users) died of prostate cancer. We collected information on antiarrhythmic drug purchases from the national prescription database. Both prediagnostic and postdiagnostic drug usages were analysed using the Cox regression method.

RESULTS

No association was found for prostate cancer death with digoxin usage before (HR 1.00, 95% CI 0.56-1.80) or after (HR 0.81, 95% CI 0.43-1.51) prostate cancer diagnosis. The results were also comparable for sotalol and antiarrhythmic drugs in general. Among men not receiving hormonal therapy, prediagnostic digoxin usage was associated with prolonged prostate cancer survival (HR 0.20, 95% CI 0.05-0.86).

CONCLUSIONS

No general protective effects against prostate cancer were observed for digoxin or sotalol usage.

Contemporary accuracy of death certificates for coding prostate cancer as a cause of death: Is reliance on death certification good enough? A comparison with blinded review by an independent cause of death evaluation committee

BACKGROUND

Accurate cause of death assignment is crucial for prostate cancer epidemiology and trials reporting prostate cancer-specific mortality outcomes.

METHODS

We compared death certificate information with independent cause of death evaluation by an expert committee within a prostate cancer trial (2002-2015).

RESULTS

Of 1236 deaths assessed, expert committee evaluation attributed 523 (42%) to prostate cancer, agreeing with death certificate cause of death in 1134 cases (92%, 95% CI: 90%, 93%). The sensitivity of death certificates in identifying prostate cancer deaths as classified by the committee was 91% (95% CI: 89%, 94%); specificity was 92% (95% CI: 90%, 94%). Sensitivity and specificity were lower where death occurred within 1 year of diagnosis, and where there was another primary cancer diagnosis.

CONCLUSIONS

UK death certificates accurately identify cause of death in men with prostate cancer, supporting their use in routine statistics. Possible differential misattribution by trial arm supports independent evaluation in randomised trials.

Non-Steroidal Anti-Inflammatory Drugs and Cancer Death in the Finnish Prostate Cancer Screening Trial

Non-steroidal anti-inflammatory drugs (NSAIDs), especially aspirin, have been associated with lowered cancer incidence and mortality. We examined overall cancer mortality and mortality from specific cancer sites among the 80,144 men in the Finnish Prostate Cancer Screening Trial. Information on prescription drug use was acquired from the national drug reimbursement database. Over-the-counter use information was gathered by a questionnaire. Hazard ratios (HR) and 95% confidence intervals (CI) by prescription and over-the-counter NSAID use for overall and specific cancer deaths were calculated using Cox regression. During the median follow-up time of 15 years, 7,008 men died from cancer. Men with prescription NSAID use had elevated cancer mortality (HR 2.02 95% CI 1.91–2.15) compared to non-users. The mortality risk was increased for lung, colorectal and pancreas cancer mortality (HR 2.68, 95%CI 2.40–2.99, HR 1.91, 95% CI 1.57–2.32 and HR 1.93, 95% CI 1.58–2.37, respectively). The increased risk remained in competing risks regression (HR 1.11, 95% CI 1.05–1.18). When the usage during the last three years of follow-up was excluded, the effect was reversed (HR 0.69, 95% CI 0.65–0.73). Cancer mortality was not decreased for prescription or over-the-counter aspirin use. However, in the competing risk regression analysis combined prescription and over-the-counter aspirin use was associated with decreased overall cancer mortality (HR 0.76, 95% CI 0.70–0.82). Cancer mortality was increased for NSAID users. However, the risk disappeared when the last 3 years were excluded.

Absolute Effect of Prostate Cancer Screening: Balance of Benefits and Harms by Center within the European Randomized Study of Prostate Cancer Screening

PURPOSE

The balance of benefits and harms in prostate cancer screening has not been sufficiently characterized. We related indicators of mortality reduction and overdetection by center within the European Randomized Study of Prostate Cancer Screening (ERSPC).

EXPERIMENTAL DESIGN

We analyzed the absolute mortality reduction expressed as number needed to invite (NNI = 1/absolute risk reduction; indicating how many men had to be randomized to screening arm to avert a prostate cancer death) for screening and the absolute excess of prostate cancer detection as number needed for overdetection (NNO = 1/absolute excess incidence; indicating the number of men invited per additional prostate cancer case), and compared their relationship across the seven ERSPC centers.

RESULTS

Both absolute mortality reduction (NNI) and absolute overdetection (NNO) varied widely between the centers: NNI, 200-7,000 and NNO, 16-69. Extent of overdiagnosis and mortality reduction was closely associated [correlation coefficient, r = 0.76; weighted linear regression coefficient, β = 33; 95% confidence interval (CI), 5-62; R(2) = 0.72]. For an averted prostate cancer death at 13 years of follow-up, 12 to 36 excess cases had to be detected in various centers.

CONCLUSIONS

The differences between the ERSPC centers likely reflect variations in prostate cancer incidence and mortality, as well as in screening protocol and performance. The strong interrelation between the benefits and harms suggests that efforts to maximize the mortality effect are bound to increase overdiagnosis and might be improved by focusing on high-risk populations. The optimal balance between screening intensity and risk of overdiagnosis remains unclear.

Use of non-steroidal anti-inflammatory drugs and prostate cancer survival in the Finnish prostate cancer screening trial

BACKGROUND

Growing evidence suggests that aspirin is associated with decreased prostate cancer (PCa) mortality. The effect of other NSAID use on risk of PCa death remains controversial. We examined prostate cancer survival among aspirin and other NSAID users in the Finnish Prostate Cancer Screening Trial.

METHODS

A total of 6,537 men were diagnosed with prostate cancer in 1996-2009 among the 80,144 men in the trial and 617 died from prostate cancer during the median follow-up of 7.5 years after the diagnosis. Prescription drug purchases information was obtained from the national reimbursement database. We calculated hazard ratios and 95% confidence intervals for PCa-specific survival using multivariable-adjusted Cox regression analysis separately for NSAID and aspirin usage before and after the diagnosis.

RESULTS

We observed an increased risk of PCa death associated with both pre- and post-diagnostic NSAID usage (HR 1.30, 95%CI 1.07-1.58 and HR 2.09, 95%CI 1.75-2.50, respectively). An increasing risk trend was observed by cumulative dose and intensity of NSAID use. When the last three years were excluded from the analysis, the death risk diminished to a protective level (HR 0.42, 95%CI 0.34-0.51 and HR 0.30 95%CI 0.24-0.39). Aspirin use was not significantly associated with prostate cancer survival.

CONCLUSIONS

The survival decrease among NSAID users is likely explained by symptomatic treatment of metastatic pain in patients with advanced PCa. However, results of the lag time analysis support previous findings of a possible preventative action of NSAIDs.

Standardisation of information submitted to an endpoint committee for cause of death assignment in a cancer screening trial – lessons learnt from CAP (Cluster randomised triAl of PSA testing for Prostate cancer)

BACKGROUND

In cancer screening trials where the primary outcome is target cancer-specific mortality, the unbiased determination of underlying cause of death (UCD) is crucial. To minimise bias, the UCD should be independently verified by expert reviewers, blinded to death certificate data and trial arm. We investigated whether standardising the information submitted for UCD assignment in a population-based randomised controlled trial of prostate-specific antigen (PSA) testing for prostate cancer reduced the reviewers' ability to correctly guess the trial arm.

METHODS

Over 550 General Practitioner (GP) practices (>415,000 men aged 50-69 years) were cluster-randomised to PSA testing (intervention arm) or the National Health Service (NHS) prostate cancer risk management programme (control arm) between 2001 and 2007. Assignment of UCD was by independent reviews of researcher-written clinical vignettes that masked trial arm and death certificate information. A period of time after the process began (the initial phase), we analysed whether the reviewers could correctly identify trial arm from the vignettes, and the reasons for their choice. This feedback led to further standardisation of information (second phase), after which we re-assessed the extent of correct identification of trial arm.

RESULTS

1099 assessments of 509 vignettes were completed by January 2014. In the initial phase (n = 510 assessments), reviewers were unsure of trial arm in 33% of intervention and 30% of control arm assessments and were influenced by symptoms at diagnosis, PSA test result and study-specific criteria. In the second phase (n = 589), the respective proportions of uncertainty were 45% and 48%. The percentage of cases whereby reviewers were unable to determine the trial arm was greater following the standardisation of information provided in the vignettes. The chances of a correct guess and an incorrect guess were equalised in each arm, following further standardisation.

CONCLUSIONS

It is possible to mask trial arm from cause of death reviewers, by using their feedback to standardise the information submitted to them.

TRIAL REGISTRATION

ISRCTN92187251.

Screening and prostate cancer mortality: results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) at 13 years of follow-up

BACKGROUND

The European Randomised study of Screening for Prostate Cancer (ERSPC) has shown significant reductions in prostate cancer mortality after 9 years and 11 years of follow-up, but screening is controversial because of adverse events such as overdiagnosis. We provide updated results of mortality from prostate cancer with follow-up to 2010, with analyses truncated at 9, 11, and 13 years.

METHODS

ERSPC is a multicentre, randomised trial with a predefined centralised database, analysis plan, and core age group (55-69 years), which assesses prostate-specific antigen (PSA) testing in eight European countries. Eligible men aged 50-74 years were identified from population registries and randomly assigned by computer generated random numbers to screening or no intervention (control). Investigators were masked to group allocation. The primary outcome was prostate cancer mortality in the core age group. Analysis was by intention to treat. We did a secondary analysis that corrected for selection bias due to non-participation. Only incidence and no mortality data at 9 years' follow-up are reported for the French centres. This study is registered with Current Controlled Trials, number ISRCTN49127736.

FINDINGS

With data truncated at 13 years of follow-up, 7408 prostate cancer cases were diagnosed in the intervention group and 6107 cases in the control group. The rate ratio of prostate cancer incidence between the intervention and control groups was 1·91 (95% CI 1·83-1·99) after 9 years (1·64 [1·58-1·69] including France), 1·66 (1·60-1·73) after 11 years, and 1·57 (1·51-1·62) after 13 years. The rate ratio of prostate cancer mortality was 0·85 (0·70-1·03) after 9 years, 0·78 (0·66-0·91) after 11 years, and 0·79 (0·69-0·91) at 13 years. The absolute risk reduction of death from prostate cancer at 13 years was 0·11 per 1000 person-years or 1·28 per 1000 men randomised, which is equivalent to one prostate cancer death averted per 781 (95% CI 490-1929) men invited for screening or one per 27 (17-66) additional prostate cancer detected. After adjustment for non-participation, the rate ratio of prostate cancer mortality in men screened was 0·73 (95% CI 0·61-0·88).

INTERPRETATION

In this update the ERSPC confirms a substantial reduction in prostate cancer mortality attributable to testing of PSA, with a substantially increased absolute effect at 13 years compared with findings after 9 and 11 years. Despite our findings, further quantification of harms and their reduction are still considered a prerequisite for the introduction of populated-based screening.

FUNDING

Each centre had its own funding responsibility.

The Finnish prostate cancer screening trial: analyses on the screening failures

Prostate cancer (PC) screening with prostate-specific antigen (PSA) has been shown to decrease PC mortality in the European Randomized Study of Screening for Prostate Cancer (ERSPC). However, in the Finnish trial, which is the largest component of the ERSPC, no statistically significant mortality reduction was observed. We investigated which had the largest impact on PC deaths in the screening arm: non-participation, interval cancers or PSA threshold. The screening (SA) and control (CA) arms comprised altogether 80,144 men. Men in the SA were screened at four-year intervals and referred to biopsy if the PSA concentration was ≥ 4.0 ng/ml, or 3.0-3.99 ng/ml with a free/total PSA ratio ≤ 16%. The median follow-up was 15.0 years. A counterfactual exclusion method was applied to estimate the effect of three subgroups in the SA: the non-participants, the screen-negative men with PSA ≥ 3.0 ng/ml and a subsequent PC diagnosis, and the men with interval PCs. The absolute risk of PC death was 0.76% in the SA and 0.85% in the CA; the observed hazard ratio (HR) was 0.89 (95% confidence interval (CI) 0.76-1.04). After correcting for non-attendance, the HR was 0.78 (0.64-0.96); predicted effect for a hypothetical PSA threshold of 3.0 ng/ml the HR was 0.88 (0.74-1.04) and after eliminating the effect of interval cancers the HR was 0.88 (0.74-1.04). Non-participating men in the SA had a high risk of PC death and a large impact on PC mortality. A hypothetical lower PSA threshold and elimination of interval cancers would have had a less pronounced effect on the screening impact.

Population-based comparative effectiveness of nephron-sparing surgery vs ablation for small renal masses

OBJECTIVE

To determine, in a population-based cohort, if disease-specific survival (DSS) was equivalent in patients undergoing ablation vs nephron-sparing surgery (NSS) for clinical stage T1a renal cell carcinoma (RCC).

PATIENTS AND METHODS

A retrospective cohort study was performed using patients from the Surveillance, Epidemiology and End Results cancer registry with RCC < 4 cm and no evidence of distant metastases, who underwent ablation or NSS. Kaplan-Meier and Cox regression analyses were performed to determine if treatment type was independently associated with DSS.

RESULTS

Between 1998 and 2007, a total of 8818 incident cases of RCC were treated with either NSS (7704) or ablation (1114). The median (interquartile range) follow-up was 2.8 (1.2-4.7) years in the NSS group and 1.6 (0.7-2.9) years in the ablation group, although 10% of each cohort were followed up beyond 5 years. After multivariable adjustment, ablation was associated with a twofold greater risk of kidney cancer death than NSS (hazard ratio 1.9, 95% confidence interval 1.1-3.3, P= 0.02). Age, gender, marital status and tumour size were also significantly associated with outcome. The predicted probability of DSS at 5 years was 98.3% with NSS and 96.6% with ablation.

CONCLUSION

After controlling for age, gender, marital status and tumour size, the typical patient presenting with clinical stage T1a RCC, who undergoes ablation rather than NSS, has a twofold increase in the risk of kidney cancer death; however, at 5 years the absolute difference is small, and may only be realized by patients with long life expectancies.

Does the source of death information affect cancer screening efficacy results? A study of the use of mortality review versus death certificates in four randomized trials

BACKGROUND

Often in randomized controlled trials of cancer screening, cause of death is determined by a mortality review committee. However, little is known regarding how findings from mortality review compare to those from death certificates alone.

PURPOSE

To examine the results of four different U. S. trials of cancer screening when death certificate data only were used, as compared to results using all available mortality review information.

METHODS

Trials included were the Health Insurance Plan of New York breast screening trial (HIP), the Minnesota trial of fecal occult blood testing, and the Johns Hopkins and Mayo Lung Projects, which each examined chest x-ray and sputum cytology. The sensitivity, specificity, positive and negative predictive values, and Cohen's kappa for death certificates were calculated for all arms of all trials. Separate intention-to-screen analyses were conducted for each trial using cause of death information from either death certificates alone or full mortality review data.

RESULTS

Generally there was excellent agreement between the death certificates and the mortality review committee as to the underlying cause of death (kappa >0.85 in all cases); death certificate agreement was similar between arms in all trials. Modest changes in the screening effectiveness estimates were observed when mortality review information was utilized, ranging from a 9% decrease to a 2% increase in the calculated mortality rate ratios. However, in one instance (HIP) a statistically significant benefit of screening was observed when mortality review committee data were used (rate ratio (RR) 0.77, 95% confidence interval (CI) 0.62- 0.95) but not when death certificate data were used (RR 0.82, 95% CI 0.65-1.03).

LIMITATIONS

Although considered to be the gold standard, even carefully conducted mortality review may result in errors in cause of death assignment.

CONCLUSIONS

For each trial, results were similar regardless of the source of cause of death information.

Design issues in cancer screening trials

Randomised controlled trials avoid many of the potential biases associated with the evaluation of cancer screening. Nevertheless there are many issues concerning the design of such trials that require careful consideration and that will influence interpretation of the results. This article discusses issues related to recruitment and randomisation, which will affect the extent to which the population studied, is representative of the eventual target population of a screening programme. It addresses sample size considerations, the use of appropriate outcome measures and the timing of the intervention. Finally, issues related to ensuring appropriate analyses are discussed.

Do we really know the cause of death of the very old? Comparison between official mortality statistics and cohort study classification

Causes of death of 625 subjects who died during the 4-year follow-up of a large population-based elderly cohort (Three-City study) were independently classified by the study adjudication committee and the national mortality register. The former used all available data about the cause of death (hospital records, medical data obtained from family physicians or specialists, and proxy interviews) and the latter used internationally standardized recommendations for processing death certificate data. Comparison showed a moderate overall agreement for underlying cause of death between the study adjudication committee and the national register (kappa = 0.51). Differences were found especially for cardiovascular diseases (20.6% of deaths from the study committee vs. 32.5% from the national register) and ill-defined causes of death (22.7 vs. 4%). The proportion of disagreement increased in participants dying at age >85 compared to those dying at age < or =70 (adjusted odds ratio = 2.46, 95% confidence interval = 1.10-5.49). It was also higher when the study committee used hospital record data for defining cause of death, compared to adjudication based on data obtained from proxy (adjusted odds ratio = 1.85, 95% CI = 1.09-3.14). These findings raise questions about the validity of national mortality registers in very old persons. Disease-specific causes of death, especially vascular diseases, could be overestimated in this age group.

Differences in Endpoints between the Swedish W-E (Two County) Trial of Mammographic Screening and the Swedish Overview: Methodological Consequences

Objectives

To characterize and quantify the differences in the number of cases and breast cancer deaths in the Swedish W-E Trial compared with the Swedish Overview Committee (OVC) summaries and to study methodological issues related to trials in secondary prevention.

Setting

The study population of the W-E Trial of mammography screening was included in the first (W and E county) and the second (E-county) OVC summary of all Swedish randomized mammography screening trials. The OVC and the W-E Trial used different criteria for case definition and causes of death determination.

Method

A Review Committee compared the original data files from Wand E county and the first and second OVC. The reason for a discrepancy was determined individually for all non-concordant cases or breast cancer deaths.

Results

Of the 2615 cases included by the W-E Trial or the OVC, there were 478 (18%) disagreements. Of the disagreements 82% were due to inclusion/exclusion criteria, and 18% to disagreement with respect to cause of death or vital status at ascertainment. For E-County, the OVC inclusion rules and register based determination of cause of death (second OVC) rather than individual case review (W-E Trial and 1st OVC) resulted in a reduction of the estimate of the effect of screening, but for W-County the difference between the original trial and the OVC was modest.

Conclusions

The conclusion that invitation to mammography screening reduces breast cancer mortality remains robust. Disagreements were mainly due to study design issues, while disagreements about cause of death were a minority. When secondary research does not adhere to the protocols of the primary research projects, the consequences of such design differences should be investigated and reported. Register linkage of trials can add follow-up information. The precision of trials with modest size is enhanced by individual monitoring of case status and outcome status such as determination of cause of death.

Components of the metabolic syndrome and risk of prostate cancer: the HUNT 2 cohort, Norway

BACKGROUND

The metabolic syndrome has been suggested as a unifying link between a "western" lifestyle and an increased prostate cancer risk.

METHODS

We assessed the associations of components of the metabolic syndrome with prostate cancer in a prospective cohort based on 29,364 Norwegian men followed up for prostate cancer incidence and mortality from 1995-1997 to the end of 2005 in the second Nord Trøndelag Health Study (HUNT 2).

RESULTS

During a mean 9.3 years follow-up, 687 incident prostate cancers were diagnosed, and 110 men died from prostate cancer. There was little evidence that baseline BMI, waist circumference, waist-hip ratio, total or HDL-cholesterol, triglycerides, presence of the metabolic syndrome, diabetes, antihypertensive use, or cardiovascular disease were associated with incident or fatal prostate cancer. There was weak evidence that raised blood pressure was associated with an increased risk: for each SD (12 mm) increase in diastolic blood pressure, there was an 8% (95% CI = 1-17%; p = 0.04) increased risk of incident prostate cancer.

CONCLUSIONS

We found little evidence to support the hypothesis that the metabolic syndrome or its components explains higher prostate cancer mortality rates in countries with a "western" diet and lifestyle. The positive association of blood pressure with prostate cancer warrants further investigation.

Lower urinary tract symptoms and risk of prostate cancer: the HUNT 2 Cohort, Norway

Screening for early prostate cancer is frequently employed in the routine management of men with lower urinary tract symptoms (LUTS), but the evidence-base linking LUTS with prostate cancer is limited. We assessed the association of LUTS with a subsequent prostate cancer diagnosis in a prospective cohort study based on 21,159 Norwegian men who completed baseline questionnaires, including the International Prostate Symptom Score (IPSS) questionnaire, between 1995 and 2007 as part of the second Nord-Trøndelag Health Study (HUNT 2). Men were followed-up for prostate cancer incidence and mortality from the date of clinical examination to end 2005. During a mean of 9 years follow-up, 518 incident prostate cancers were diagnosed and 74 men died from prostate cancer. Men with severe LUTS (IPSS 20-35) had a 2.26-fold (95% CI: 1.49-3.42) increased risk of prostate cancer compared to men reporting no symptoms. A positive association was observed for localized (hazard ratio, HR: 4.61; 2.23-9.54), but not advanced (HR: 0.51; 0.15-1.75), cancers (p for heterogeneity <0.001). There was no evidence that moderate/severe symptoms (IPSS 8-35) were associated with prostate cancer mortality (HR: 0.83; 0.42-1.64) vs. no symptoms. Amongst 518 men with prostate cancer, there was a 46% lower (10-68%) risk of death with moderate/severe symptoms vs. no symptoms. We conclude that LUTS are positively associated with localized, but not advanced or fatal, prostate cancer, suggesting that urinary symptoms are not caused by prostate cancer. Thus, screening for early cancers on the basis of LUTS may not be justified.