Publications by authors named "Amy M F Yen"

Objectives: To identify issues of principle and practice giving rise to misunderstandings in reviewing evidence, to illustrate these by reference to the Nordic Cochrane Review (NCR) and its interpretation of two trials of mammographic screening, and to draw lessons for future reviewing of published results.

Methods: A narrative review of the publications of the Nordic Cochrane Review of mammographic screening (NCR), the Swedish Two-County Trial (S2C) and the Canadian National Breast Screening Study 1 and 2 (CNBSS-1 and CNBSS-2).

Results: The NCR concluded that the S2C was unreliable, despite the review's complaints being shown to be mistaken, by direct reference to the original primary publications of the S2C.

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Introduction: The efficacy of smoking cessation intervention has been proven with randomized controlled trials. Our study aims to elucidate the effects of the delivery method of smoking cessation advice on the process of stage of changes with transtheorectical model underpinning in a community setting.

Methods: A total of 436 subjects were recruited in a quasi-experimental untreated control design study, with 46 receiving advice from healthcare professionals (HCP group) and 390 in the control group, in 2003, Nantou, Taiwan.

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Objective: This study focused on recent changes in the incidence of colorectal cancer (CRC) in Khon Kaen, Thailand. Methods: Data for CRC over the period 1989 to 2012 from the population-based cancer registry of Khon Kaen province were employed. Age-standardized incidence rates (ASR) were calculated and classified into 4 age-groups for comparison.

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The similarity between the structure and function of the breast and prostate has been known for a long time, but there are serious discrepancies in the terminology describing breast and prostate cancers. The use of the large, thick-section (3D) histology technique for both organs exposes the irrationality of the breast cancer terminology. Pathologists with expertise in diagnosing prostate cancer take the anatomic site of cancer origin into account when using the terms AAP (acinar adenocarcinoma of the prostate) and DAP (ductal adenocarcinoma of the prostate) to distinguish between the prostate cancers originating primarily from the fluid-producing acinar portion of the organ (AAP) and the tumors originating either purely from the larger ducts (DAP) or from both the acini and the main ducts combined (DAP and AAP).

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Background: Woman have lower rate of hypertension than man but it is still elusive how such gender difference can be explained by kinetic epidemiological curves.

Objective: The aim of this paper was to develop a multi-state model for delineating the kinetic epidemiology of hypertension according to the Seventh Report of the Joint National Committee (JNC 7) classification criteria by gender, and to derive gender-specific kinetic curves.

Methods: We used data from a population-based screening programme with 42,027 participants to fit a four-state Markov model corresponding to the classification of hypertension from the JNC 7.

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Rationale, Aims And Objectives: Population-based randomized controlled trials (RCTs) often involve enormous costs and long-term follow-up to evaluate primary end points. Analytical decision-simulated model for sample size and effectiveness projections based on primary and surrogate end points are necessary before planning a population-based RCT.

Method: Based on the study design similar to two previous RCTs, transition rates were estimated using a five-state natural history model [normal, preclinical detection phase (PCDP) Dukes' A/B, PCDP Dukes' C/D, Clinical Dukes' A/B and Clinical Dukes' C/D].

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Objectives: Economic appraisal of an intervention is a complex and multivariable problem, with probabilistic issues related not only to clinical outcomes but also to costs and willingness to pay.

Methods: We provide a comprehensive framework for economic appraisal of a health intervention to prevent beast cancer mortality, involving probabilistic model of costs as well as of aspects of the disease process. The economic appraisal can give a range of probabilities of cost-effectiveness depending on willingness or ability to pay.

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Homogeneous multi-state models of disease progression have been widely used for designing and evaluating cancer screening programs. However, in screening for premalignant conditions of the cervix or large bowel, it is unlikely that all premalignant lesions have the same underlying propensity for progression. Incorporating frailty into multi-state models raises practical difficulties as it precludes the derivation of finite transition probabilities by matrix solution of the Kolmogorov equations.

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Objectives: To estimate the absolute numbers of breast cancer deaths prevented and the absolute numbers of tumours overdiagnosed in mammographic screening for breast cancer at ages 50-69 years.

Setting: The Swedish Two-County randomized trial of mammographic screening for breast cancer, and the UK Breast Screening Programme in England, ages 50-69 years.

Methods: We estimated the absolute numbers of deaths avoided and additional cases diagnosed in the study group (active study population) of the Swedish Two-County Trial, by comparison with the control group (passive study population).

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Strong evidence supports the value of breast cancer screening with mammography, and high-quality mammography screening can be considered a major public health achievement. As noted earlier in the discussion about the evaluation of service screening, the group of women who did not participate in mammographic screening in the decades after screening had been introduced had essentially unchanged or only minor improvements in mortality compared with the pattern before the introduction of screening, despite widespread use of adjuvant chemotherapy or hormonal therapy. Breast cancer should be treated in its preclinical phase if we are to save the lives of women with this disease, and a considerable body of evidence outlines best practices that, with broader adherence, would result in greater breast cancer mortality reductions than have been observed to date.

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Eight randomized controlled trials of mammography screening have been conducted to date. In addition to evaluating the efficacy of screening with an experimental design, the trials provided investigators with access to information about breast cancers much earlier in their development than had previously been available. The trials of mammographic screening provide conclusive evidence that the policy of offering screening is associated with a significant and substantial reduction in breast cancer mortality.

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