Benefits Of Screening Tests Research Articles

Methodological Considerations in Evaluating Breast Cancer Screening Studies.

In evidence-based medicine frameworks, the highest level of evidence is derived from quantitative synthesis of double-masked, high-quality, randomly assigned controlled trials. Meta-analyses of randomly assigned controlled trials have demonstrated that screening mammography reduces breast cancer deaths. In the United States, every major guideline-producing organization has recommended screening mammography in average-risk women; however, there are controversies about age and frequency. Carefully controlled observational research studies and statistical modeling studies can address evidence gaps and inform evidence-based, contemporary screening practices. As breast imaging radiologists develop and evaluate existing and new screening tests and technologies, they will need to understand the key methodological considerations and scientific criteria used by policy makers and health service researchers to support dissemination and implementation of evidence-based screening tests. The Wilson and Jungner principles and the U.S. Preventive Services Task Force general analytic framework provide structured evaluations of the effectiveness of screening tests. Key considerations in both frameworks include public health significance, natural history of disease, cost-effectiveness, and characteristics of screening tests and treatments. Rigorous evaluation of screening tests using analytic frameworks can maximize the benefits of screening tests while reducing potential harms. The purpose of this article is to review key methodological considerations and analytic frameworks used to evaluate screening studies and develop evidence-based recommendations.

Cost-effectiveness Analysis of Colorectal Cancer Screening Strategies Using Active Learning and Monte Carlo Simulation.

Detection of colorectal cancer (CRC) in the early stages through available screening tests increases the patient's survival chances. Multimodal screening policies can benefit patients by providing more diverse screening options and balancing the risks and benefits of screening tests. We investigate the cost-effectiveness of a wide variety of multimodal CRC screening policies. We developed a Monte Carlo simulation framework to model CRC dynamics. We proposed an innovative calibration process using machine learning models to estimate age- and size-specific adenomatous polyps' progression and regression rates. The proposed approach significantly expedites the model parameter space search. Two multimodal proposed policies (i.e., 1] colonoscopy at 50 y and fecal occult blood test annually between 60 and 75 y and 2] colonoscopy at 50 and 60 y and fecal immunochemical test annually between 70 and 75 y) are identified as efficient frontier policies. Both policies are cost-effective at a willingness to pay of $50,000. Sensitivity analyses were performed to assess the sensitivity of results to a change in screening test costs as well as adherence behavior. The sensitivity analysis results suggest that the proposed policies are mostly robust to the considered changes in screening test costs, as there is a significant overlap between the efficient frontier policies of the baseline and the sensitivity analysis cases. However, the efficient frontier policies were more sensitive to changes in adherence behavior. Generally, combining stool-based tests with visual tests will benefit patients with higher life expectancy and a lower expected cost compared with unimodal screening policies. Colonoscopy at younger ages (when the colonoscopy complication risk is lower) and stool-based tests at older ages are shown to be more effective. We propose a detailed Markov model to capture the colorectal cancer (CRC) dynamics. The proposed Markov model presents the detailed dynamics of adenomas progression to CRC.We use more than 44,000 colonoscopy reports and available data in the literature to calibrate the proposed Markov model using an innovative approach that leverages machine learning models to expedite the calibration process.We investigate the cost-effectiveness of a wide variety of multimodal CRC screening policies and compare their performances with the current in-practice policies.

ConfidentCare: A Clinical Decision Support System for Personalized Breast Cancer Screening

Breast cancer screening policies attempt to achieve timely diagnosis by regularly screening healthy women via various imaging tests. Various clinical decisions are needed to manage the screening process: selecting initial screening tests, interpreting test results, and deciding if further diagnostic tests are required. Current screening policies are guided by clinical practice guidelines (CPGs), which represent a “one-size-fits-all” approach, designed to work well (on average) for a population, and can only offer coarse expert-based patient stratification that is not rigorously validated through data. Since the risks and benefits of screening tests are functions of each patient's features, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">personalized screening policies</i> tailored to the features of individuals are desirable. To address this issue, we developed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ConfidentCare</i> : a computer-aided clinical decision support system that learns a personalized screening policy from electronic health record (EHR) data. By a “personalized screening policy,” we mean a clustering of women's features, and a set of customized screening guidelines for each cluster. ConfidentCare operates by computing clusters of patients with similar features, then learning the “best” screening procedure for each cluster using a supervised learning algorithm. The algorithm ensures that the learned screening policy satisfies a predefined accuracy requirement with a high level of confidence for every cluster. By applying ConfidentCare to real-world data, we show that it outperforms the current CPGs in terms of cost efficiency and false positive rates: a reduction of 31 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> in the false positive rate can be achieved.

Testing whether barriers to a hypothetical screening test affect unrelated perceived benefits and vice versa: A randomised, experimental study

ObjectiveDetermine whether (fictitious) health screening test benefits affect perceptions of (unrelated) barriers, and barriers affect perceptions of benefits. MethodsUK adults were recruited via an online survey panel and randomised to receive a vignette describing a hypothetical screening test with either high or low benefits (higher vs. lower mortality reduction) and high or low barriers (severe vs. mild side-effects; a 2×2 factorial design). ANOVAs compared mean perceived benefits and barriers scores. Screening ‘intentions’ were compared using Pearson’s χ2 test. ResultsBenefits were rated less favourably when barriers were high (mean: 27.4, standard deviation: 5.3) than when they were low (M: 28.5, SD: 4.8; p=0.010, partial η2=0.031). Barriers were rated more negatively when benefits were low (M: 17.1, SD: 7.6) than when they were high (M: 15.7, SD: 7.3; p=0.023, partial η2=0.024). Most intended to have the test in all conditions (73–81%); except for the low benefit-high barrier condition (37%; p<0.0005; N=218). ConclusionsPerceptions of test attributes may be influenced by unrelated characteristics. Practice implicationsReducing screening test barriers alone may have suboptimal effects on perceptions of barriers if benefits remain low; increasing screening benefits may not improve perceptions of benefits if barriers remain high.

In Searching of Colorectal Cancer Screening Tools Suitable for Resource-limited Countries

Colorectal cancer (CRC) has traditionally been one of the commonest malignant disorders in western populations, whereas cancers of the upper gastro-intestinal tract (esophagus and stomach) and liver have predominated in the east. The last two decades has witnessed a dramatic rise in CRC incidence and mortality in Asia. The Asia Pacific region represents a diversified population with disparities in disease prevalence, health belief attitudes and healthcare infrastructure. Although CRC is considered to be closely related to environmental factors, particularly diet and lifestyle, effective methods for primary prevention have yet to be established. The best near-term option for decreasing the burden of CRC is therefore screening for early cancer and precancerous lesions. There is strong evidence that screening for colorectal cancer improves survival. Current international practice guidelines and expert consensus statements recommend CRC screening for people over 50 years. The public, in general, is poorly informed about the rising incidence of CRC and the benefits of screening tests. Financial constrains appear to be a major hurdle to implement screening program. Clinical studies showed that colonic neoplasms are predominantly found in the distal colon. Yet 50% of patients with proximal colonic lesions have normal distal colon. With the existing infrastructure and health care system, it would be very difficult, if not impossible, to perform CRC screening for the whole population older than 50 years of age. Among several modalities that have been proposed for colorectal cancer screening, the fecal occult blood test (FOBT) or Hemoccult test has been demonstrated in three landmark randomized controlled trials to reduce mortality from this cancer In Searching of Colorectal Cancer Screening Tools Suitable for Resource-limited Countries

The Ethics of Information: Absolute Risk Reduction and Patient Understanding of Screening

Some experts have argued that patients should routinely be told the specific magnitude and absolute probability of potential risks and benefits of screening tests. This position is motivated by the idea that framing risk information in ways that are less precise violates the ethical principle of respect for autonomy and its application in informed consent or shared decision-making. In this Perspective, we consider a number of problems with this view that have not been adequately addressed. The most important challenges stem from the danger that patients will misunderstand the information or have irrational responses to it. Any initiative in this area should take such factors into account and should consider carefully how to apply the ethical principles of respect for autonomy and beneficence.

Cervical cancer screening: knowledge of Pap smear benefits and utilization in Mexico

To identify and evaluate the predisposing factors regarding the utilization of the Pap smears in the population seen in the Cervical Cancer Screening Program in Mexico A cross-sectional study was conducted from January 1997 through December 1998 in Mexico city. A questionnaire was applied to a total of 2,107 women of reproductive age who attended a family planning program and data was collected regarding the following topics: social-demographics, reproductive risk factors associated with cervical cancer, sexual behavior and partner history, birth control, knowledge about Pap smear' benefits, and its utilization. Statistic analysis was conducted using Student' s test and non-conditional multiple logistic regression model for determining significance. The predisposing factors were: knowledge about Pap smear's benefits (OR=6.00, CI 95% 4.70-7.67), history of using at least two birth control methods (OR=2.38, CI 95% 1.75-3.24), previous history of vaginal infection (OR=2.18, CI 95% 1.73-2.75), sexual partner's approval of gynecological examinations (OR=1.56, CI 95% 1.07-2.29). Educational programs on cancer prevention in this population should include the benefits of screening tests. Pap smears for Mexican women of reproductive age are mostly offered opportunely. The previous use of health services is a determinant factor for the utilization of the Cervical Cancer Screening Program. These results show the need to strengthen health promotion programs to women at high risk of cervical cancer and their sexual partners.

Screening for Chlamydia trachomatis in adolescent males: a cost-based decision analysis.

To evaluate the cost and benefits of screening tests for Chlamydia trachomatis in adolescent males, we developed a decision analysis model and compared the leukocyte esterase urine dipstick test with culture, with direct-smear fluorescent antibody (DFA), and with the option of no screening (no treatment). The leukocyte esterase test has the lowest average cost-per-cure ($51) compared with direct-smear fluorescent antibody ($192) and culture ($414). Compared with the DFA, we estimate that the leukocyte esterase test saves over $9,727 per cohort of 1,000 sexually active adolescent males screened. Sensitivity analyses show the leukocyte esterase test results in a lower cost-per-cure and lower overall costs (per cohort) than culture and direct-smear fluorescent antibody at any prevalence of C. trachomatis infection, and lower overall costs (per cohort) than no screening at prevalences above 21 percent.

Evaluation of benefits of screening tests done immediately on admission to hospital.

Evidence was sought of improved inpatient progress and reduced hospital costs when a battery of investigations were done at the time a patient was admitted to hospital. The outcome in 500 admission-tested patients was compared with that in two other groups of 500 control patients. No significant differences were found among the three groups in a variety of indices of inpatient progress. Because of an estimated 64% increase in the cost of investigating inpatients with admission testing, the total cost of hospital care was increased by about 5%. Under the conditions of this study, admission testing added to the cost of hospitalization, without associated evidence of benefit to the patient.

The Boston XYY Case

O n June 20, newspapers reported that Dr. Stanley Walzer, a Harvard psychiatrist, had curtailed a controversial chromosome screening study which detected male children with the XYY chromosome pattern. Dr. Walzer's decision was the outcome of a year-and-ahalf of charges and counter-charges which swirled around the study, its methods, its legitimacy, its scientific value, and ultimately around the tactics used to oppose the study. In the latter half of 1974 the question of whether the study should continue was taken up first by the Harvard Medical School standing committee on medical research, then by the human studies committee, and finally by the full medical school faculty. Though all these bodies ruled in the study's favor, critics remained unsatisfied. Indeed, earlier opponents (a Science for the People group, informally led by Dr. Jonathan Beckwith at Harvard and Dr. Jonathan King of MIT) were joined by the Washington-based Children's Defense Fund. Dr. Walzer attributes his decision to cease the screening portion of his study to the emotionally exhausting atmosphere created by the controversy.' For the moment, then, the debate in Boston may be settled; the issues which fueled it are not. Our society has entered a period in which it is technically possible to characterize the genotypes of large numbers of individuals by relatively simple biochemical or chromosomal screening tests. The potential benefits and risks of these tests vary enormously. The early detection of PKU (phenylketonuria) can prevent an incipient genetic disease, and hence has clear health benefits. In other cases-like the XYY genotype-the benefits of screening tests are more problematic. In the midand late sixties, studies of the chromosome composition of inmates in mental-penal institutions revealed that roughly two percent had the XYY chromosome type. At the same time the incidence of XYY in studies of consecutive newborns was determined to be about 0.11 percent.2 This higher-thanexpected rate of XYY individuals in prisons and mental hospitals led to association of the chromosome with "aggressive or sexual psychopathology." This premature characterization of the genotype, coupled with wide-spread publicity, has raised the definite possibility of stigmatization for individuals found to have the XYY genotype. These initial blunders have seriously jeopardized the possibility of further study. Statistically speaking, the vast majority of XYYs are not likely to end up in institutions. Assuming (for purposes of calculation) that one in 500 adult white males are in mental-penal institutions, in every group of one million males there would be 1100 XYYs, about forty of whom would be in mental-penal institutions at some point in their lives.3 From this illustrative calculation, it may also be inferred that approximately 1070 out of 1100 XYYs, or more than ninety-seven percent, will probably not end up in mental-penal institutions; for many of them the prospects are simply to lead normal, socially productive lives. As Ernest Hook points out, "Discovery of an extra sex chromosome in a male hardly predicts antisocial behavior with the confidence, for instance, that the observation of trisomy 21 (the chromosome pattern associated with mongolism) predicts mental retardation."4 Similarly, after an extensive review of the literature on the XYY genotype, Digamber Borgaonkar and Saleem Shah conclude: "In view of the phenotypic heterogeneity which clearly seems to accompany the XYY chromosomal constitution, it would be incorrect to suppose a narrow range of phenotypic variation or that a typical syndrome exists."5