42 resultados para mammography screening
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
Screening for malignant disease aims to reduce the population risk of impaired health due to the tumor in question. Screening does not only entail testing but covers all steps required to achieve the intended reduction in risk, from the appropriate information of the population to a suitable therapy. Screening tests are performed in individuals free or unaware of any symptoms associated with the tumor. An essential condition is a recognizable pathological abnormality, which occurs without symptoms and represents a pre-clinical, early stage of the tumor. Overdiagnosis and overtreatment have only recently been recognized as important problems of screening for malignant disease. Overdiagnosis is defined as a screening-detected tumor that would never have led to symptoms. In prostate-specific antigen (PSA) screening for prostate cancer 50 % - 70 % of screening-detected cancers represent such overdiagnoses. Similarly, in the case of mammography screening 20 % - 30 % of screening-detected breast cancers are overdiagnoses. The evaluation of screening interventions is often affected by biases such as healthy screenee effects or length and lead time bias. Randomized controlled trials are therefore needed to examine the efficacy and effectiveness of screening interventions and to define the rate of adverse outcomes such as unnecessary diagnostic evaluations, overdiagnosis and overtreatment. Unfortunately there is no independent Swiss body comparable to the National Screening Committee in the United Kingdom or the United States Preventive Services Task Force, which examines screening tests and programs and develops recommendations. Clearly defined goals, a central organization responsible for inviting eligible individuals, documentation and quality assurance and balanced information of the public are important attributes of successful screening programs. In Switzerland the establishment of such programs is hampered by the highly fragmented, Federal health system which allows patients to access specialists directly.
Resumo:
Nur wenige Vorsorgeuntersuchungen sind so umfassend in randomisiert-kon- trollierten Studien (RCTs) untersucht worden wie das Screening auf Brustkrebs mit Hilfe der Mammografie. Es liegen derzeit acht große randomisiert-kontrol- lierte Studien und mehrere Meta-Analysen vor. Letztere kommen mehrheitlich zum Schluss, dass sich die Brustkrebssterblichkeit durch Mammografie-Screening um etwa 20 % senken lässt. Dies bedeutet im Schweizer Kontext, dass etwa 1 von 1'000 Frauen weniger an Brustkrebs stirbt, wenn Frauen ab dem 50. Lebensjahr zehn Jahre lang gescreent werden. Andererseits führt das Screening auch zu Überdiagnosen und Übertherapien. So nimmt die Zahl der Brustkrebsdiagnosen um etwa 20 % zu, was zu einer entsprechenden Zunahme an chirurgischen Ein- griffen, Strahlen- und Chemotherapien führt. Über zehn Jahre gerechnet, erhal- ten etwa 4 von 1'000 Frauen eine Brustkrebsdiagnose, die sie ohne Screening nicht erhalten hätten. Etwa 200 von 1'000 Frauen sind im Verlaufe von zehn Jahren (fünf Screening-Runden) mit abklärungsbedürftigen Befunden konfron- tiert, wobei es sich dabei mehrheitlich um falsch positive Befunde handelt. Gleichzeitig werden auch mit einem Screening-Programm 20 bis 30 % der Brust- krebse nicht im Screening erfasst. Die Information der Bevölkerung bezüglich des Mammografie-Screenings ist derzeit noch mangelhaft. Dies führt dazu, dass der mögliche Nutzen von den betroffenen Frauen überschätzt und der Schaden unterschätzt wird. Die Aufklärung der Bevölkerung im Hinblick auf Nutzen und Risiken des Mammografie-Screenings muss daher verbessert werden, denn Frau- en haben einen Anspruch auf evidenzbasierte Informationen und eine „infor- mierte Entscheidung“.
Resumo:
Our commentary of the article “‘Screening’ for Breast Cancer: Misguided Research Misinforming Public Policies” has two main parts. First we address some of the methodological points raised by Professor Miettinen. Then we review more specific aspects of the Swiss Medical Board statement on mammography screening for early detection of breast cancer.
Resumo:
OBJECTIVE: To determine the prevalence and independent predictors of significant atherosclerotic renal artery stenosis (RAS) in unselected hypertensive patients undergoing coronary angiography and to assess the 6-month outcome of those patients with a significant RAS. METHODS: One thousand, four hundred and three consecutive hypertensive patients undergoing drive-by renal arteriography were analyzed retrospectively. Univariate and multivariate logistic regression analyses were performed to identify independent predictors of RAS. In patients with significant RAS (>or=50% luminal narrowing), 6-month follow-up was assessed and outcome was compared between patients with or without renal revascularization. RESULTS: The prevalence of significant RAS was 8%. After multivariate analysis, coronary [odds ratio 5.3; 95% confidence interval (CI) 2.7-10.3; P < 0.0001], peripheral (odds ratio 3.3; 95% CI 2.0-5.5; P < 0.0001), and cerebral artery (odds ratio 2.8; 95% CI 1.5-5.3; P = 0.001) diseases, and impaired renal function (odds ratio 2.9; 95% CI 1.8-4.5; P < 0.0001) were found as independent predictors. At least one of these predictors was present in 96% of patients with RAS. In 74 patients (66%) with significant RAS, an ad hoc revascularization was performed. At follow-up, creatinine clearance was significantly higher in revascularized than in nonrevascularized patients (69.2 vs. 55.5 ml/min per 1.73 m, P = 0.029). By contrast, blood pressure was comparable between both groups, but nonrevascularized patients were taking significantly more antihypertensive drugs as compared with baseline (2.7 vs. 2.1, follow-up vs. baseline; P = 0.0066). CONCLUSION: The prevalence of atherosclerotic RAS in unselected hypertensive patients undergoing coronary angiography was low. Coronary, peripheral, and cerebral artery diseases, and impaired renal function were independent predictors of RAS. Ad hoc renal revascularization was associated with better renal function and fewer intake of antihypertensive drugs at follow-up.
Resumo:
AIM: To assess the prevalence of mild cognitive impairment (MCI) in medical inpatients aged 55-85 years without known cognitive deficits, and how often ward physicians mentioned MCI in their discharge notes. Moreover, we aimed to identify variables associated with MCI and to assess the sensitivity and specificity of the Mini-Mental State Examination (MMSE) for MCI. METHODS: Two neuropsychologists administered a 60-min battery of validated tests to evaluate different cognitive domains. The diagnosis of MCI was based on a prespecified algorithm. The sensitivity and specificity of the MMSE for MCI were calculated. RESULTS: Fifteen patients showed a normal cognitive profile (21.4%), while 55 patients (78.6%) showed MCI. Ward physicians, blinded to the results of the neuropsychological evaluation, did not mention MCI in their discharge notes of any of the evaluated patients. The only variable independently associated with MCI was the MMSE. A MMSE score of < or =28 showed a sensitivity of 85.5% and a specificity of 66.7% for MCI. CONCLUSION: MCI is frequent albeit overlooked in elderly medical inpatients without previously known cognitive deficits. In view of therapies preventing the progression of MCI to dementia, MCI screening will be crucial. The MMSE represents a promising screening tool for MCI in medical inpatients.
Resumo:
Introduction: The aim of the present work was to verify whether calculating a ratio between clotting times obtained with the sensitive PTT-LA and a less sensitive activated partial thromboplastin time (aPTT)-reagent may represent a valuable aPTT-based screening strategy for lupus anticoagulants (LA). Methods: For the pilot study, plasma samples from normal subjects (n = 15) and from patients with LA (n = 10), therapeutic anticoagulation with vitamin K-antagonists (VKA) (n = 15) or unfractionated heparin (n = 15), coagulation factors deficiency (n = 16), and inhibitory antibodies against factor VIII or IX (n = 11) were studied. For the evaluation study, 1553 consecutive plasma samples from nonanticoagulated patients investigated for LA between January 2005 and December 2007 at our institution were studied. Following screening strategies were employed: Pathromtin-SL (aPTT-SL), PTT-LA (aPTT-LA), ratio aPTT-LA/aPTT-SL (aPTT-ratio), and Russell's viper venom (RVV) based LA-Check. LA positive samples were identified by mixing studies and diluted RVV confirmation test (LA-Check/LA-Sure). Results: Pilot study: All screening strategies had a 100% sensitivity, and the aPTT-ratio reached the highest specificity (82%; 95%CI: 74-90%). Within the evaluation study, following sensitivities for LA screening were observed: aPTT-SL 59.0% (95%CI: 57-61%), aPTT-LA 82.1% (95%CI: 80-84%), aPTT-ratio 92.3% (95%CI: 91-94), and LA-Check 83.3% (95%CI: 82-85%). Conclusion: Calculating a ratio between the LA-sensitive PTT-LA and the less sensitive Pathromtin-SL improves the performance of the PTT-LA itself and represents a simple and sensitive aPTT-based integrated strategy for LA screening.
Resumo:
Screening people without symptoms of disease is an attractive idea. Screening allows early detection of disease or elevated risk of disease, and has the potential for improved treatment and reduction of mortality. The list of future screening opportunities is set to grow because of the refinement of screening techniques, the increasing frequency of degenerative and chronic diseases, and the steadily growing body of evidence on genetic predispositions for various diseases. But how should we decide on the diseases for which screening should be done and on recommendations for how it should be implemented? We use the examples of prostate cancer and genetic screening to show the importance of considering screening as an ongoing population-based intervention with beneficial and harmful effects, and not simply the use of a test. Assessing whether screening should be recommended and implemented for any named disease is therefore a multi-dimensional task in health technology assessment. There are several countries that already use established processes and criteria to assess the appropriateness of screening. We argue that the Swiss healthcare system needs a nationwide screening commission mandated to conduct appropriate evidence-based evaluation of the impact of proposed screening interventions, to issue evidence-based recommendations, and to monitor the performance of screening programmes introduced. Without explicit processes there is a danger that beneficial screening programmes could be neglected and that ineffective, and potentially harmful, screening procedures could be introduced.
Resumo:
Repeated Chlamydia trachomatis infections after treatment are common. One reason is reinfection from untreated partners in ongoing sexual partnerships. Mathematical models that are used to predict the impact of screening on reducing chlamydia prevalence often do not incorporate reinfection and might overestimate the expected impact. We describe a pair compartmental model that explicitly incorporates sexual partnership duration and reinfection. The pair model predicts a weaker impact of screening when compared directly with a model that does not accommodate partnerships. Effective management of sex partners to prevent reinfection might need to be strengthened in chlamydia control programs.
Resumo:
To assess the impact of screening programmes in reducing the prevalence of Chlamydia trachomatis, mathematical and computational models are used as a guideline for decision support. Unfortunately, large uncertainties exist about the parameters that determine the transmission dynamics of C. trachomatis. Here, we use a SEIRS (susceptible-exposed-infected-recovered-susceptible) model to critically analyze the turnover of C. trachomatis in a population and the impact of a screening programme. We perform a sensitivity analysis on the most important steps during an infection with C. trachomatis. Varying the fraction of the infections becoming symptomatic as well as the duration of the symptomatic period within the range of previously used parameter estimates has little effect on the transmission dynamics. However, uncertainties in the duration of temporary immunity and the asymptomatic period can result in large differences in the predicted impact of a screening programme. We therefore analyze previously published data on the persistence of asymptomatic C. trachomatis infection in women and estimate the mean duration of the asymptomatic period to be longer than anticipated so far, namely 433 days (95% CI: 420-447 days). Our study shows that a longer duration of the asymptomatic period results in a more pronounced impact of a screening programme. However, due to the slower turnover of the infection, a substantial reduction in prevalence can only be achieved after screening for several years or decades.
Resumo:
Background. An important question for chlamydia control programs is the extent to which finding and treating prevalent, asymptomatic Chlamydia trachomatis genital infection reduces reproductive sequelae in infected women. Methods. We reviewed the literature to critically evaluate evidence on the effect of chlamydia screening on development of sequelae in infected women. Results. Two randomized controlled trials of 1-time screening for chlamydial infection—in a Seattle-area health maintenance organization and a Danish school district—revealed that screening was associated with an ∼50% reduction in the incidence of pelvic inflammatory disease over the following year. However, both of these trials had methodological issues that may have affected the magnitude of observed screening benefits and might limit generalizability to other populations. A large, nonrandomized cohort of chlamydia screening among US Army recruits, although limited by lack of outpatient data, did not find a benefit of similar magnitude to the randomized trials. Methodological limitations restrict valid conclusions about individual benefits of screening using data from historical cohorts and ecological studies. We identified no trials directly evaluating the effect of chlamydia screening on subclinical tubal inflammation or damage, ectopic pregnancy, or tubal factor infertility and no studies addressing the effects of >1 round of screening, the optimal frequency of screening, or the benefits of screening for repeat infections. Conclusions. Additional studies of the effectiveness of chlamydia screening would be valuable; feasible study designs may depend on the degree to which screening programs are already established. In addition, better natural history data on the timing of tubal inflammation and damage after C. trachomatis infection and development of more accurate, noninvasive tools to assess chlamydial sequelae are essential to informing chlamydia control efforts.
Resumo:
The multi-target screening method described in this work allows the simultaneous detection and identification of 700 drugs and metabolites in biological fluids using a hybrid triple-quadrupole linear ion trap mass spectrometer in a single analytical run. After standardization of the method, the retention times of 700 compounds were determined and transitions for each compound were selected by a "scheduled" survey MRM scan, followed by an information-dependent acquisition using the sensitive enhanced product ion scan of a Q TRAP hybrid instrument. The identification of the compounds in the samples analyzed was accomplished by searching the tandem mass spectrometry (MS/MS) spectra against the library we developed, which contains electrospray ionization-MS/MS spectra of over 1,250 compounds. The multi-target screening method together with the library was included in a software program for routine screening and quantitation to achieve automated acquisition and library searching. With the help of this software application, the time for evaluation and interpretation of the results could be drastically reduced. This new multi-target screening method has been successfully applied for the analysis of postmortem and traffic offense samples as well as proficiency testing, and complements screening with immunoassays, gas chromatography-mass spectrometry, and liquid chromatography-diode-array detection. Other possible applications are analysis in clinical toxicology (for intoxication cases), in psychiatry (antidepressants and other psychoactive drugs), and in forensic toxicology (drugs and driving, workplace drug testing, oral fluid analysis, drug-facilitated sexual assault).
Resumo:
Since the late 1990s and early 2000s, derivatives of well-known designer drugs as well as new psychoactive compounds have been sold on the illicit drug market and have led to intoxications and fatalities. The LC-MS/MS screening method presented covers 31 new designer drugs as well as cathinone, methcathinone, phencyclidine, and ketamine which were included to complete the screening spectrum. All but the last two are modified molecular structures of amphetamine, tryptamine, or piperazine. Among the amphetamine derivatives are cathinone, methcathinone, 3,4-DMA, 2,5-DMA, DOB, DOET, DOM, ethylamphetamine, MDDMA, 4-MTA, PMA, PMMA, 3,4,5-TMA, TMA-6 and members of the 2C group: 2C-B, 2C-D, 2C-H, 2C-I, 2C-P, 2C-T-2, 2C-T-4, and 2C-T-7. AMT, DPT, DiPT, MiPT, DMT, and 5MeO-DMT are contained in the tryptamine group, BZP, MDBP, TFMPP, mCPP, and MeOPP in the piperazine group. Using an Applied Biosystems LC-MS/MS API 365 TurboIonSpray it is possible to identify all 35 substances. After addition of internal standards and mixed-mode solid-phase extraction the analytes are separated using a Synergi Polar RP column and gradient elution with 1 mM ammonium formate and methanol/0.1% formic acid as mobile phases A and B. Data acquisition is performed in MRM mode with positive electro spray ionization. The assay is selective for all tested substances. Limits of detection were determined by analyzing S/N-ratios and are between 1.0 and 5.0 ng/mL. Matrix effects lie between 65% and 118%, extraction efficiencies range from 72% to 90%.