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Systematic reviews as a 'lens of evidence': Determinants of benefits and harms of breast cancer screening.

ABSTRACT: This systematic review, stimulated by inconsistency in secondary evidence, reports the benefits and harms of breast cancer (BC) screening and their determinants according to systematic reviews. A systematic search, which identified 9,976 abstracts, led to the inclusion of 58 reviews. BC mortality reduction with screening mammography was 15-25% in trials and 28-56% in observational studies in all age groups, and the risk of stage III+ cancers was reduced for women older than 49 years. Overdiagnosis due to mammography was 1-60% in trials and 1-12% in studies with a low risk of bias, and cumulative false-positive rates were lower with biennial than annual screening (3-17% vs 0.01-41%). There is no consistency in the reviews' conclusions about the magnitude of BC mortality reduction among women younger than 50 years or older than 69 years, or determinants of benefits and harms of mammography, including the type of mammography (digital vs screen-film), the number of views and the screening interval. Similarly, there was no solid evidence on determinants of benefits and harms or BC mortality reduction with screening by ultrasonography or clinical breast examination (sensitivity ranges, 54-84% and 47-69%, respectively), and strong evidence of unfavourable benefit-to-harm ratio with breast self-examination. The reviews' conclusions were not dependent on the quality of the reviews or publication date. Systematic reviews on mammography screening, mainly from high-income countries, systematically disagree on the interpretation of the benefit-to-harm ratio. Future reviews are unlikely to clarify the discrepancies unless new original studies are published.

SUBMITTER: Mandrik O

PROVIDER: S-EPMC6619055 | biostudies-other | 2019 Aug

REPOSITORIES: biostudies-other

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Systematic reviews as a 'lens of evidence': Determinants of benefits and harms of breast cancer screening.

Mandrik Olena O Zielonke Nadine N Meheus Filip F Severens J L Hans JLH Guha Neela N Herrero Acosta Rolando R Murillo Raul R

International journal of cancer 20190314 4

This systematic review, stimulated by inconsistency in secondary evidence, reports the benefits and harms of breast cancer (BC) screening and their determinants according to systematic reviews. A systematic search, which identified 9,976 abstracts, led to the inclusion of 58 reviews. BC mortality reduction with screening mammography was 15-25% in trials and 28-56% in observational studies in all age groups, and the risk of stage III+ cancers was reduced for women older than 49 years. Overdiagnos ...[more]

PMID: 30762235

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Project description:Lung cancer is the leading cause of cancer death. Most patients are diagnosed with advanced disease, resulting in a very low 5-year survival. Screening may reduce the risk of death from lung cancer.To conduct a systematic review of the evidence regarding the benefits and harms of lung cancer screening using low-dose computed tomography (LDCT). A multisociety collaborative initiative (involving the American Cancer Society, American College of Chest Physicians, American Society of Clinical Oncology, and National Comprehensive Cancer Network) was undertaken to create the foundation for development of an evidence-based clinical guideline.MEDLINE (Ovid: January 1996 to April 2012), EMBASE (Ovid: January 1996 to April 2012), and the Cochrane Library (April 2012).Of 591 citations identified and reviewed, 8 randomized trials and 13 cohort studies of LDCT screening met criteria for inclusion. Primary outcomes were lung cancer mortality and all-cause mortality, and secondary outcomes included nodule detection, invasive procedures, follow-up tests, and smoking cessation.Critical appraisal using predefined criteria was conducted on individual studies and the overall body of evidence. Differences in data extracted by reviewers were adjudicated by consensus.Three randomized studies provided evidence on the effect of LDCT screening on lung cancer mortality, of which the National Lung Screening Trial was the most informative, demonstrating that among 53,454 participants enrolled, screening resulted in significantly fewer lung cancer deaths (356 vs 443 deaths; lung cancer?specific mortality, 274 vs 309 events per 100,000 person-years for LDCT and control groups, respectively; relative risk, 0.80; 95% CI, 0.73-0.93; absolute risk reduction, 0.33%; P = .004). The other 2 smaller studies showed no such benefit. In terms of potential harms of LDCT screening, across all trials and cohorts, approximately 20% of individuals in each round of screening had positive results requiring some degree of follow-up, while approximately 1% had lung cancer. There was marked heterogeneity in this finding and in the frequency of follow-up investigations, biopsies, and percentage of surgical procedures performed in patients with benign lesions. Major complications in those with benign conditions were rare.Low-dose computed tomography screening may benefit individuals at an increased risk for lung cancer, but uncertainty exists about the potential harms of screening and the generalizability of results.

Project description:BackgroundThere has been increased interest in the role of cannabis for treating medical conditions. The availability of different cannabis-based products can make the side effects of exposure unpredictable. We sought to conduct a scoping review of systematic reviews assessing benefits and harms of cannabis-based medicines for any condition.MethodsA protocol was followed throughout the conduct of this scoping review. A protocol-guided scoping review conduct. Searches of bibliographic databases (e.g., MEDLINE®, Embase, PsycINFO, the Cochrane Library) and gray literature were performed. Two people selected and charted data from systematic reviews. Categorizations emerged during data synthesis. The reporting of results from systematic reviews was performed at a high level appropriate for a scoping review.ResultsAfter screening 1975 citations, 72 systematic reviews were included. The reviews covered many conditions, the most common being pain management. Several reviews focused on management of pain as a symptom of conditions such as multiple sclerosis (MS), injury, and cancer. After pain, the most common symptoms treated were spasticity in MS, movement disturbances, nausea/vomiting, and mental health symptoms. An assessment of review findings lends to the understanding that, although in a small number of reviews results showed a benefit for reducing pain, the analysis approach and reporting in other reviews was sub-optimal, making it difficult to know how consistent findings are when considering pain in general. Adverse effects were reported in most reviews comparing cannabis with placebo (49/59, 83%) and in 20/24 (83%) of the reviews comparing cannabis to active drugs. Minor adverse effects (e.g., drowsiness, dizziness) were common and reported in over half of the reviews. Serious harms were not as common, but were reported in 21/59 (36%) reviews that reported on adverse effects. Overall, safety data was generally reported study-by-study, with few reviews synthesizing data. Only one review was rated as high quality, while the remaining were rated of moderate (n = 36) or low/critically low (n = 35) quality.ConclusionsResults from the included reviews were mixed, with most reporting an inability to draw conclusions due to inconsistent findings and a lack of rigorous evidence. Mild harms were frequently reported, and it is possible the harms of cannabis-based medicines may outweigh benefits.Systematic review registrationThe protocol for this scoping review was posted in the Open Access (https://ruor.uottawa.ca/handle/10393/37247).

Project description:BACKGROUND:Controversy persists about optimal mammography screening strategies. OBJECTIVE:To evaluate screening outcomes, taking into account advances in mammography and treatment of breast cancer. DESIGN:Collaboration of 6 simulation models using national data on incidence, digital mammography performance, treatment effects, and other-cause mortality. SETTING:United States. PATIENTS:Average-risk U.S. female population and subgroups with varying risk, breast density, or comorbidity. INTERVENTION:Eight strategies differing by age at which screening starts (40, 45, or 50 years) and screening interval (annual, biennial, and hybrid [annual for women in their 40s and biennial thereafter]). All strategies assumed 100% adherence and stopped at age 74 years. MEASUREMENTS:Benefits (breast cancer-specific mortality reduction, breast cancer deaths averted, life-years, and quality-adjusted life-years); number of mammograms used; harms (false-positive results, benign biopsies, and overdiagnosis); and ratios of harms (or use) and benefits (efficiency) per 1000 screens. RESULTS:Biennial strategies were consistently the most efficient for average-risk women. Biennial screening from age 50 to 74 years avoided a median of 7 breast cancer deaths versus no screening; annual screening from age 40 to 74 years avoided an additional 3 deaths, but yielded 1988 more false-positive results and 11 more overdiagnoses per 1000 women screened. Annual screening from age 50 to 74 years was inefficient (similar benefits, but more harms than other strategies). For groups with a 2- to 4-fold increased risk, annual screening from age 40 years had similar harms and benefits as screening average-risk women biennially from 50 to 74 years. For groups with moderate or severe comorbidity, screening could stop at age 66 to 68 years. LIMITATION:Other imaging technologies, polygenic risk, and nonadherence were not considered. CONCLUSION:Biennial screening for breast cancer is efficient for average-risk populations. Decisions about starting ages and intervals will depend on population characteristics and the decision makers' weight given to the harms and benefits of screening. PRIMARY FUNDING SOURCE:National Institutes of Health.

Project description:BackgroundAn estimated 20-30% of community-dwelling Canadian adults aged 65 years or older experience one or more falls each year. Fall-related injuries are a leading cause of hospitalization and can lead to functional independence. Many fall prevention interventions, often based on modifiable risk factors, have been studied. Apart from the magnitude of the benefits and harms from different interventions, the preferences of older adults for different interventions as well as the relative importance they place on the different potential outcomes may influence recommendations by guideline panels. These reviews on benefits and harms of interventions, and on patient values and preferences, will inform the Canadian Task Force on Preventive Health Care to develop recommendations on fall prevention for primary care providers.MethodsTo review the benefits and harms of fall prevention interventions, we will update a previous systematic review of randomized controlled trials with adaptations to modify the classification of interventions and narrow the scope to community-dwelling older adults and primary-care relevant interventions. Four databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Ageline), reference lists, trial registries, and relevant websites will be searched, using limits for randomized trials and date (2016 onwards). We will classify interventions according to the Prevention of Falls Network Europe (ProFANE) Group's taxonomy. Outcomes include fallers, falls, injurious falls, fractures, hip fractures, institutionalization, health-related quality of life, functional status, and intervention-related adverse effects. For studies not included in the previous review, screening, study selection, data extraction on outcomes, and risk of bias assessments will be independently undertaken by two reviewers with consensus used for final decisions. Where quantitative analysis is suitable, network or pairwise meta-analysis will be conducted using a frequentist approach in Stata. Assessment of the transitivity and coherence of the network meta-analyses will be undertaken. For the reviews on patient preferences and outcome valuation (relative importance of outcomes), we will perform de novo reviews with searches in three databases (MEDLINE, PsycInfo, and CINAHL) and reference lists for cross-sectional, longitudinal quantitative, or qualitative studies published from 2000. Selection, data extraction, and risk of bias assessments suitable for each study design will be performed in duplicate. The analysis will be guided by a narrative synthesis approach, which may include meta-analysis for health-state utilities. We will use the CINeMa approach to a rate the certainty of the evidence for outcomes on intervention effects analyzed using network meta-analysis and the GRADE approach for all other outcomes.DiscussionWe will describe the flow of literature and characteristics of all studies and present results of all analyses and summary of finding tables. We will compare our findings to others and discuss the limitations of the reviews and the available literature.Systematic review registrationThis protocol has not been registered.

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Systematic reviews as a 'lens of evidence': Determinants of benefits and harms of breast cancer screening.

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Systematic reviews as a 'lens of evidence': Determinants of benefits and harms of breast cancer screening.

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