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PubMed2005

Re-interpreting the data on the cost and effectiveness of population screening for colorectal cancer in Australia.

Three studies report estimates of the cost and effectiveness of alternate strategies for screening the average-risk Australian population for colorectal cancer. The options considered are faecal occult blood testing, double contrast barium enema, sigmoidoscopy and colonoscopy. At present, there is no consensus over which screening method is optimal by the economic criterion. Also, the existing studies report a mixture of average and incremental cost-effectiveness ratios derived from data collected between 1994 and 2002. We suggest average cost-effectiveness ratios are not useful for decision-making and illustrate how they differ from the preferred incremental cost-effectiveness ratio. We then update the cost data reported in the three studies to 2002 prices and calculate incremental cost-effectiveness ratios where not previously available. Our re-analysis of one study contradicts the conclusions drawn by the authors, who had only calculated average cost-effectiveness ratios. In particular, we find their recommendation of population screening with colonoscopy would cause, annually, between 33 and 1,322 years of life to be lost and between M17 dollars and M87 dollars to be wasted. Based on updated cost data and the incremental analysis, our findings indicate that population screening using biennial faecal occult blood testing (39,459 dollars per life-year gained), annual faecal occult blood testing (30,556 dollars per life-year gained) and colonoscopy (26,587 dollars per life-year gained) are cost-effective. Hence, the decision over which method of screening is optimal remains ambiguous across the three studies. We recommend policy-makers choose the study they believe produces the most accurate estimates of cost and health effect, identify their willingness to pay for health benefits and consider other issues relevant to the decision.

Editorial↗

PubMed1996

Population screening for haemochromatosis: a unifying analysis of published intervention trials.

OBJECTIVES: To examine the efficacy of population screening for haemochromatosis by analysing the screening performance of seven intervention trials, and to compare this with the expected performance derived from family studies. SETTING: Seven population intervention trials carried out between 1983 and 1995 in Australia, Scandinavia, Iceland, and the United State. METHODS: Seven of 23 English language trials identified were suitable for the meta-analysis. Transferrin saturation and serum ferritin measurements derived from family studies were used to predict detection and false positive rates for each trial. RESULTS: The seven trials used various screening and diagnostic criteria. A total of 18,396 men and 12,254 women were screened. Because some cases were not detected by screening, and some screen positive individuals did not complete diagnostic testing, the prevalence of homozygous individuals was underestimated in all the trials. The reported and predicted percentages of screen positive individuals nearly always agreed. The homozygote prevalence was estimated to be 34 men and 40 women per 10,000 (prevalence predicted from family studies is 53 per 10,000). Clinical manifestations were present in 50% of male and 44% of female homozygotes. CONCLUSIONS: False positive rates, homozygote prevalences, and frequency of clinical manifestations were in general agreement with predictions from family studies. However, incomplete understanding about a number of issues requires that further pilot trials be carried out before screening can be considered part of routine medical practice.

Adult↗

PubMed1997

Analysis of the cost of population screening for haemochromatosis using biochemical and genetic markers.

AIMS: To estimate the cost of population screening for haemochromatosis in Australia and to compare the cost of alternative screening strategies. METHODS: The costs of screening for haemochromatosis were analysed in a hypothetical study using transferrin saturation as the primary screening test, with confirmation of the diagnosis by either liver biopsy or DNA testing for the recently-described haemochromatosis gene. RESULTS: Screening, with confirmation of the diagnosis by liver biopsy, would cost between US$5079 and US$8813 per case detected (excluding administrative costs), depending on the screening strategy (Aust$ = US$0.80). If a DNA test were used instead of liver biopsy, the cost would be reduced to an estimated US$3954-US$4410 per case. This would be further reduced to US$2457 by detection of additional cases by screening family members. The least costly strategy utilised a transferrin saturation threshold of 55% and DNA testing for confirmation of the diagnosis; however, a transferrin saturation threshold of 45% increased the cost only marginally. The initial screening step (transferrin saturation) accounted for 74%-94% of the estimated cost of the screening programme. CONCLUSIONS: Screening for haemochromatosis using transferrin saturation involves relatively modest costs which may be recovered if complications of haemochromatosis can be prevented by early detection and treatment. The most cost-effective strategies utilised transferrin saturation for initial screening, followed by DNA testing. Reduction in the cost of transferrin saturation would lead to a significant reduction in total screening costs. Additional benefits of a screening programme include detection of other iron overload disorders and iron deficiency.

Biopsy↗

PubMed2003

Effectiveness and cost of screening for abdominal aortic aneurysm: results of a population screening program.

OBJECTIVES: We undertook this study to calculate the cost per life-year gained in the first round of a screening program for abdominal aortic aneurysm (AAA) and to estimate the costs in a subsequent round. METHODS: This was an intervention study, with follow-up for ruptured aneurysms. Men older than 50 years were screened for asymptomatic AAA. Outcome measures included cost per life-year saved and number of men needed to be screened to save one life. RESULTS: The incidence of ruptured AAA was 2.6 per 10,000 person- years in the screening group and 7.1 per 10,000 person-years in the control group. Screening is estimated to have prevented 10.8 ruptured AAA and 8 deaths per year, gaining 51 life-years per year for the study population, and to have reduced the incidence of ruptured AAA by 64% (95% CI, 42%-77%). Each life-year gained during the first screening round cost $1107. To save one life, 1000 men need to be screened and 5 elective operations performed. We predict that a second round of screening can be cost neutral. CONCLUSIONS: The cost-effectiveness of screening for AAA compares favorably with screening programs for other disorders in adults.

Aged↗

PubMed1982

Paired cervical smears: a method of reducing the false-negative rate in population screening.

Cervical smears taken by the wooden Ayre spatula (widely used in the United Kingdom) and by a plastic spatula (Armovical) were compared for their ability to detect dysplastic cervical epithelium and endocervical cells. At the same time, the value of taking duplicate smears was assessed. Paired cervical smears were obtained at a single attendance from 21,352 women, using the 2 types of spatulas in 4 different sequences. Although individually the Armovical proved superior to the Ayre spatula for the collection of endocervical epithelial material, this advantage was not complemented by any marked improvement in its detection of cervical dysplasia. Paired smear sampling, however, was clearly more rewarding in this respect and also allowed the introduction of laboratory quality control, as each preparation of any given pair was examined by a different screener. The false-negative rate was 18.5%: it comprised 11.1% sampling error and 7.4% screening error. It is concluded that paired smear sampling in population screening would significantly reduce the false-negative rate.

Carcinoma in Situ↗

PubMed2004

Effectiveness of smoking cessation self-help materials in a lung cancer screening population.

Randomized controlled trials of smoking interventions have not been well-documented for lung cancer screening populations. In this study, we randomly assigned 171 current smokers who were undergoing low-dose fast spiral chest CT (SCTS) for lung cancer screening to receive either standard written self-help materials or a written list of Internet resources for smoking cessation. At the 1-year follow-up, more of the subjects receiving Internet-based resources reported making a stop attempt (68% versus 48%, P=0.011). However, there were no statistically significant differences in 7-day point prevalence quit rates (5% versus 10%) or advancement in motivational readiness to stop smoking (27% versus 30%), respectively, between the groups. Clearly, more investigation is warranted into how to tailor smoking interventions for cancer screening participants.

Aged↗

PubMed2000

Population screening for hemochromatosis: has the time finally come?

Hemochromatosis refers to a group of common heritable disorders among Western Caucasians which increase susceptibility for development of iron overload and its complications. These consequences are preventable by early detection and simple, relatively inexpensive treatment. Screening of appropriate populations to detect hemochromatosis before iron overload occurs is both effective and cost-effective. The primary goal of screening should be the ongoing detection of persons with hemochromatosis, especially healthy individuals whose risk to develop iron overload is great, in a context that provides appropriate preventive treatment, education, and counseling. Although related issues warrant further study, implementation of well-designed screening programs for hemochromatosis should not be delayed.

Genetic Testing↗

PubMed2005

Prevalence and risk of colorectal neoplasia in consumers of alcohol in a screening population.

BACKGROUND AND AIMS: Although studies suggest a positive association between alcohol consumption and risk for colorectal neoplasia, the impact on screening has not been fully examined. It is also unclear whether all types of alcohol are associated with an increased risk. We performed a cross-sectional study to examine the impact of regular alcohol consumption on the detection of significant colorectal neoplasia in a screening population. METHODS: Data collected for 2,291 patients presenting for screening colonoscopy: known risk factors for colorectal neoplasia and alcohol drinking pattern. Our outcome was the endoscopic detection of significant colorectal neoplasia, which included adenocarcinoma, high-grade dysplasia, villous tissue, adenomas 1 cm or greater and multiple (>2) adenomas of any size. RESULTS: When compared to abstainers, we found an increased risk for significant neoplasia in those patients who consumed more than eight drinks of spirits alcohol (26.3%; OR = 2.53; 95% CI = 1.10-4.28; p < 0.01) and those who drank more than eight servings of beer per week (21.7%; OR = 2.43; 95% CI = 1.11-5.32; p= 0.02). Consuming one to eight glasses of wine per week was associated with a decreased risk for significant neoplasia (OR = 0.55; 95% CI = 0.34-0.87; p < 0.01). CONCLUSIONS: While there was a more than twofold increased risk of significant colorectal neoplasia in people who drink spirits and beer, people who drank wine had a lower risk. In our sample, people who drank more than eight servings of beer or spirits per week had at least a one in five chance of having significant colorectal neoplasia detected by screening colonoscopy.

Adenocarcinoma↗

PubMed2000

Population screening reduces mortality rate from aortic aneurysm in men.

BACKGROUND: Rupture of an unsuspected abdominal aortic aneurysm is a major cause of death in men over the age of 65 years. A significant reduction in deaths is likely to result only from higher rates of detection and increased numbers of elective aneurysm repairs. Screening of men reaching the age of 65 years has been taking place in the county of Gloucestershire, UK since 1990 and the aim of this study was to investigate any change in the mortality rate from aortic aneurysm in the screened portion of the population. METHODS: Total number of deaths from all aortic aneurysm-related causes in the county's population was calculated from hospital and post-mortem records, together with computerized death certificate records, for the years 1994-1998. The overall number of aneurysm-related deaths in men aged 65-73 years, who have been progressively influenced by the screening programme, was compared with that for men of all other ages. RESULTS: The total number of aneurysm-related deaths in men aged 65-73 years decreased progressively year by year between 1994 and 1998; this reduction is highly statistically significant (P < 0. 001). No such change was observed in the unscreened part of the population. CONCLUSION: Screening for asymptomatic abdominal aortic aneurysm results in a significant reduction in numbers of deaths from all aneurysm-related causes in the screened portion of the male population.

Aged↗

PubMed1973

Effects of observer variation in population screening for cervical carcinoma.

A stratified random sample of 100 cervical smears was taken from routine population screening material and graded by three cytological laboratories. The sensitivity of the smear test for detecting cervical malignancies varied from 72 to 88%-a difference of 16%; for all serve epithelial abnormalities the sensitivity varied from 52 to 71% (a difference of 19%). The histological material pertaining to these smears was re-examined ;blindly' and then sent for diagnosis to a second pathologist. Using each set of histodiagnoses as reference, the sensitivity of the test for detecting cervical malignancies varied from 77 to 85%-a difference of 8%; the sensitivity for all epithelial abnormalities varied from 62 to 76% (a difference of 14%). The significance of these observer variations on the efficacy of screening for cervical carcinoma is discussed.

Carcinoma↗

PubMed1999

Cystic fibrosis: molecular diagnosis, population screening, and public policy.

OBJECTIVE: To review the current status of scientific knowledge and opinion regarding molecular genetic testing of mutations in the CFTR gene for purposes of diagnosis and population carrier screening of cystic fibrosis (CF). DATA SOURCES: Published research findings on the nature of the CFTR gene, pilot population screening studies in the United States and Europe, and ongoing deliberations of professional and governmental agencies considering implementation of widespread testing. STUDY SELECTION: Findings relevant to the molecular heterogeneity of CFTR mutations and its implications for population carrier screening were considered. DATA EXTRACTION: Information was extracted from studies published by us and others, as made available to recent consensus panels and professional committees. DATA SYNTHESIS: These data were reevaluated in light of recent movements in professional and public policy regarding acceptability and desirability of widespread CF mutation testing. Effects to date of such testing on patient outcomes is reported. CONCLUSIONS: The ability to test for CFTR mutations at the molecular level has already improved the diagnosis of symptomatic patients and expanded the reproductive options of family members of CF patients. The same technology also holds promise of identifying asymptomatic carriers and at-risk couples without family history in the general population so that they too might be offered prenatal diagnosis or other options. However, a number of key questions remain to be worked out before a widespread national screening program can be put into practice. These include the target population to be offered testing (the entire population vs high-risk ethnic groups), the size and nature of the mutation test panel (universal vs ethnic specific), the inclusion or exclusion of CFTR variants that do not cause classical CF, the optimal testing technology, appropriate standards for laboratory quality assurance, and the development of sufficient educational materials and genetic counseling resources for test delivery, reporting, and interpretation. The answers to these questions will be relevant not only to CF testing but also to many other large-scale molecular genetic screening programs being considered in the future.

Cloning, Molecular↗

PubMed2006

Does PSA velocity predict prostate cancer in pre-screened populations?

UNLABELLED: PSA-driven screening has been applied to a large part of the male population in many countries. An elevated PSA in secondary screens may indicate benign enlargement of the prostate rather than prostate cancer. In such cases the yearly rate of increase of PSA (PSA velocity [PSAV]) may improve the test characteristics of PSA. MATERIALS AND METHODS: Data from the European Randomized Study of Screening for Prostate Cancer Rotterdam are used to study the issue. Relative sensitivity, relative specificity, and positive predictive value (PPV) are calculated. Logistic regression analysis is used to compare odds ratios for positive biopsies. The relationship between PSAV and parameters of tumour aggressiveness is investigated. RESULTS: Five hundred eighty-eight consecutive participants were identified who presented at their first screening with PSA values <4.0 and who progressed to PSA values >4.0 ng/ml four years later. None were biopsied in round one, all were biopsied in round two. Relative sensitivity and specificity depend strongly on PSAV cut-offs of 0.25-1.0 ng/ml/yr. The use of PSAV cut-offs does not improve the PPV of the PSA cut-off of 4.0 ng/ml, nor do any of the PSAV cut-offs improve the odds ratio for identifying prostate cancer with respect to the cut-off value of 4.0 ng/ml. The rate of aggressive cancers seems to increase with increasing PSAV. CONCLUSIONS: PSAV does not improve the detection characteristics of a PSA cut-off of 4.0 ng/ml in secondary screening after four years.

Aged↗

PubMed1996

Population screening for haemochromatosis: expectations based on a study of relatives of symptomatic probands.

OBJECTIVES: The frequency of symptomatic haemochromatosis in the general population and the potential efficacy of population screening is uncertain. Data from family members of clinically diagnosed index cases were used to estimate the frequency of the haemochromatosis genotype, the proportion of homozygous individuals with clinical manifestations, and the efficacy of transferrin saturation and serum ferritin measurements as screening tests. SETTING: English language studies from Europe, North America, and Australia. METHODS: Haemochromatosis zygosity was classified only by HLA haplotyping, the most reliable available method. All subsequent analyses were based on family members classified in this way. RESULTS: An estimated 53 individuals per 10,000 are homozygous for haemochromatosis. Overall, 67% of male and 41% of female family members display at least one clinical manifestation; for men, the frequency increases with age. Transferrin saturation levels are 70% or above in an estimated 72% of homozygous men, along with three per 1000 heterozygous or unaffected men. Transferrin saturation levels are 60% or above in an estimated 67% of homozygous women, along with six per 1000 heterozygous or unaffected women. Serum ferritin levels, but not transferrin saturation levels, are associated with clinical manifestations. CONCLUSIONS: This information can be used to compare expected versus actual screening performance for intervention trials aimed at detecting haemochromatosis in the general population.

Adult↗

PubMed2003

Population screening for prostate cancer and emerging concepts for young men.

Prostate cancer is the most common malignancy in American men, accounting for > 29% of all diagnosed cancers and approximately 13% of all cancer deaths. Nearly 1 of every 6 men will be diagnosed with the disease at some time in their lives. In 2003 alone, an estimated 221000 men in the United States will be diagnosed with prostate cancer and > 28000 will die of the disease. An elevated level of prostate-specific antigen (PSA) is correlated with the presence of prostate cancer, and since 1989 we have been living in the "PSA era," in which the PSA screening test is widely used in clinical practice. This article summarizes what has been learned about the use of PSA screening, including the intricacies of free PSA, PSA doubling time, and various factors that may affect PSA and confound screening in young men. Although population-based screening for prostate cancer has yet to be definitively proven to affect disease-specific mortality, PSA testing is detecting cancers in younger men and at earlier stages of disease progression and, partly as a result, 5-year cancer-specific survival is increasing. Even though this lead-time effect may not translate into long-term improvement, these changes are very promising and are a necessary prerequisite to effective screening. For patients at high risk with a family history of the disease and for black men, a strategy consisting of an annual PSA blood test and digital rectal examination for men >or=40 years of age appears to be prudent. Use of age- and race-specific reference ranges for PSA based on sensitivity, or maximal cancer detection, is the most appropriate approach in this high-risk group. Specifically among black men 40-49 years of age, those with a PSA value > 2.0 ng/mL should consider further evaluation. Many men at low/average risk aged 40-49 years also request testing and it is reasonable to offer testing and risk assessment to these young men. The exact screening threshold for total PSA in these men is unknown, but 95% of these men will have a PSA < 2.5 ng/mL. Prostate-specific antigen velocity, percentage of free PSA, and perhaps complexed PSA may be used to help determine risk, but further study of young men is needed. In the future, a risk-stratified approach using molecular biomarkers and/or proteomics in young men is anticipated.

Adult↗

PubMed1997

[Automated cytophotomorphometric tests of blood smears in general clinical studies and population screening].

Automation of routine operations of photomorphometry of blood smears realized in the MEKOS-C cytoanalyzer helped create a new level of using a set of cytological tests, such as assessment of the leukocyte and erythrocyte formulae and of the histogram of hemoglobin distribution in red cells, estimation of leukocyte subtypes, assessment of the characteristics of the nucleolar system and the nucleoli-forming sites. Automated complex analysis of an increase in the measured characteristics of red and white blood cells impossible in common microscopy and flow cytoanalyzers appreciably improves the sensitivity and accuracy of tests and extends the range of their application. Low cost of analysis of a blood smear permits the use of MEKOS-C not only in clinical studies, but even in overall prophylactic screenings of the population.

Automation↗

PubMed2005

Model to predict prostate biopsy outcome in large screening population with independent validation in referral setting.

OBJECTIVES: To develop a model capable of predicting prostate biopsy outcomes in a large screening population, with independent validation in the referral setting. METHODS: Data from 3814 men participating in the Tyrol screening project were used to develop the model. Prospectively collected data from two independent sites in the United States (Virginia Mason Clinic, Seattle, Wash and Stanford University, Stanford, Calif) were used to validate the model independently. The Tyrol data was split randomly into three cross-validation sets, and a feed-forward, back error-propagation artificial neural network (ANN) was alternately trained on a combination of two of these data sets and validated on the remaining data set. Similarly, three logistic regression (LR) models were produced and validated using identical cross-validation data sets. The Tyrol model with the median area under receiver operating characteristic curve (AUROC) was then validated against the Virginia Mason (n = 491) and Stanford University (n = 483) data sets. RESULTS: The AUROCs for the three cross-validations were 0.74, 0.76, and 0.75 for the ANN and 0.75, 0.76, and 0.75 for the LR models. The mean AUROC for both ANN and LR was 0.75 with a standard deviation of 0.009 for ANN and 0.006 for LR. The AUROCs for the Virginia Mason and Stanford University data were 0.74 (both ANN and LR) and 0.73 (ANN) and 0.72 (LR), respectively. CONCLUSIONS: This model, designed to predict the prostate biopsy outcome, performed accurately and consistently when validated with data from two independent referral centers in the United States, suggesting that it generalizes well and may be of clinical utility to a broad range of patients.

Aged↗

PubMed2005

Diabetes-related symptoms and negative mood in participants of a targeted population-screening program for type 2 diabetes: The Hoorn Screening Study.

OBJECTIVE: To determine the level of diabetes-related symptom distress and its association with negative mood in subjects participating in a targeted population-screening program, comparing those identified as having type 2 diabetes vs. those who did not. RESEARCH DESIGN AND METHODS: This study was conducted within the framework of a targeted screening project for type 2 diabetes in a general Dutch population (age 50-75 years). The study sample consisted of 246 subjects, pre-selected on the basis of a high-risk profile; 116 of whom were subsequently identified as having type 2 diabetes, and 130 who were non-diabetic subjects. Diabetes-related symptom distress and negative mood was assessed approximately 2 weeks, 6 months, and 12 months after the diagnosis of type 2 diabetes, with the Type 2 Diabetes Symptom Checklist and the Negative well-being sub scale of the Well-being Questionnaire (W-BQ12), respectively. RESULTS: Screening-detected diabetic patients reported significantly greater burden of hyperglycemic (F = 6.0, df = 1, p = 0.015) and of fatigue (F = 5.3, df = 1, p = 0.023) symptoms in the first year following diagnosis type 2 diabetes compared to non-diabetic subjects. These outcomes did not change over time. The total symptom distress (range 0-4) was relatively low for both screening-detected diabetic patients (median at approximately 2 weeks, 6 months, and 12 months; 0.24, 0.24, 0.29) and non-diabetic subjects (0.15, 0.15, 0.18), and not significantly different. No average difference and change over time in negative well-being was found between screening-detected diabetic patients and non-diabetic subjects. Negative well-being was significantly positive related with the total symptom distress score (regression coefficient beta = 2.86, 95% CI 2.15-3.58). CONCLUSIONS: The screening-detected diabetic patients were bothered more by symptoms of hyperglycemia and fatigue in the first year following diagnosis type 2 diabetes than non-diabetic subjects. More symptom distress is associated with increased negative mood in both screening-detected diabetic patients and non-diabetic subjects.

Affect↗

PubMed1979

Ratio of 11-desoxy 17-oxosteroids to creatinine in a population screened for breast cancer.

During a population-based screening project for breast cancer, almost 15,000 women aged 50 years and over have provided a 12 h (overnight) sample of urine for research purposes. In 3,789 women the excretion of 11-desoxy-17-oxosteroids (DOOS) and creatinine was measured. Results were analysed in terms of urinary concentrations and of a ratio between DOOS and creatinine. Age had an effect on DOOS, creatinine and their ratio. Body weight and body surface area had an effect on creatinine excretion and therefore on the ratio. The following variables did not have an appreciable effect on the above-mentioned ratio: a family history of breast cancer, parity and age at first pregnancy, menopause and oestrogenic drugs, and parenchymal pattern of the breast as observed on the xeromammogram. Breast cancer was found at first screening in 106 out of 14,697 women. In 100 of these cases DOOS and creatinine were measured. Excretion values expressed as the ratio between the two, allowing for body surface area, did not differ materially from those of 100 age-matched controls. These results lead the authors to the conclusion that the determination of androgen metabolite excretion in women over 50 years of age is of no help in selecting a group at high risk of breast cancer.

17-Ketosteroids↗