Systematic reviews as a “lens of evidence”: determinants of participation in breast cancer screening

OBJECTIVE: To assess determinants of the participation rate in breast cancer screening (BCS) programs by conducting a systematic review of reviews. METHODS: We conducted a systematic search in Pubmed via Medline, Scopus, Embase, and Cochrane identifying the literature up to April 2019. Out of 2,258 revealed unique abstracts, we included 31 reviews from which 25 were considered as systematic. We applied the Walsh & McPhee Systems Model of Clinical Preventive Care to systematise the determinants of screening participation. RESULTS: The reviews, mainly in high-income settings, reported a wide range for BCS participation rate: 16-90%. The determinants of BCS participation were simple low-cost interventions, such as invitation letters, basic information on screening, multiple reminders, fixed appointments, prompts from healthcare professionals, and healthcare organizational factors (eg. close proximity to screening facility). More complex interventions (such as face-to-face counselling or home visits), mass media or improved access to transport should not be encouraged by policy makers unless other information appears. The repeated participation in mammography screening was consistently high, above 62%. Previous positive experience with screening influenced the repeated participation in screening programs. The reviews were inconsistent in the use of terminology related to BCS participation, which may have contributed to the heterogeneity in the reported outcomes. CONCLUSIONS: This study shows that consistent findings of systematic reviews bring more certainty into the conclusions on effects of simple invitation techniques, fixed appointments and prompts, as well as healthcare organizational factors on promoting participation rate in screening mammography

What determines the effects and costs of breast cancer screening?

__Background:__ Multiple reviews demonstrated high variability in effectiveness and cost-effectiveness outcomes among studies on breast cancer screening (BCS) programmes. No study to our knowledge has summarized the current evidence on determinants of effectiveness and cost-effectiveness of the most used BCS approaches or tried to explain differences in conclusions of systematic reviews on this topic. Based on published reviews, this systematic review aims to assess the degree of variability of determinants for (a) effectiveness and (b) cost-effectiveness of BCS programmes using mammography, clinical breast examination, breast self-examination, ultrasonography, or their combinations among the general population. __Methods:__ We will perform a comprehensive systematic literature search in Cochrane, Scopus, Embase, and Medline (via Pubmed). The search will be supplemented with hand searching of references of the included reviews, with hand searching in the specialized journals, and by contacting prominent experts in the field. Additional search for grey literature will be conducted on the websites of international cancer associations and networks. Two trained research assistants will screen titles and abstracts of publications independently, with at least random 10% of all abstracts being also screened by the principal researcher. The full texts of the systematic reviews will then be screened independently by two authors, and disagreements will be solved by consensus. The included reviews will be grouped by publication year, outcomes, designs of original studies, and quality. Additionally, for reviews published since 2011, transparency in reporting will be assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist for the review on determinants of effectiveness and a modified PRISMA checklist for the review on determinants for cost-effectiveness. The study will apply the Assessing the Methodological Quality of Systematic Reviews checklist to assess the methodological quality of systematic reviews. We will report the data extracted from the systematic reviews in a systematic format. Meta-meta-analysis of extracted data will be conducted when feasible. __Discussion:__ This systematic review of reviews will examine the degree of variability in the effectiveness and cost-effectiveness of BCS programmes. _Systematic review registration:_ PROSPERO CRD42016050764and CRD42016050765

What determines the effects and costs of breast cancer screening?

__Background:__ Multiple reviews demonstrated high variability in effectiveness and cost-effectiveness outcomes among studies on breast cancer screening (BCS) programmes. No study to our knowledge has summarized the current evidence on determinants of effectiveness and cost-effectiveness of the most used BCS approaches or tried to explain differences in conclusions of systematic reviews on this topic. Based on published reviews, this systematic review aims to assess the degree of variability of determinants for (a) effectiveness and (b) cost-effectiveness of BCS programmes using mammography, clinical breast examination, breast self-examination, ultrasonography, or their combinations among the general population. __Methods:__ We will perform a comprehensive systematic literature search in Cochrane, Scopus, Embase, and Medline (via Pubmed). The search will be supplemented with hand searching of references of the included reviews, with hand searching in the specialized journals, and by contacting prominent experts in the field. Additional search for grey literature will be conducted on the websites of international cancer associations and networks. Two trained research assistants will screen titles and abstracts of publications independently, with at least random 10% of all abstracts being also screened by the principal researcher. The full texts of the systematic reviews will then be screened independently by two authors, and disagreements will be solved by consensus. The included reviews will be grouped by publication year, outcomes, designs of original studies, and quality. Additionally, for reviews published since 2011, transparency in reporting will be assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist for the review on determinants of effectiveness and a modified PRISMA checklist for the review on determinants for cost-effectiveness. The study will apply the Assessing the Methodological Quality of Systematic Reviews checklist to assess the methodological quality of systematic reviews. We will report the data extracted from the systematic reviews in a systematic format. Meta-meta-analysis of extracted data will be conducted when feasible. __Discussion:__ This systematic review of reviews will examine the degree of variability in the effectiveness and cost-effectiveness of BCS programmes. _Systematic review registration:_ PROSPERO CRD42016050764and CRD42016050765

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

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 falsepositive 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

Impact of colorectal cancer screening on cancer-specific mortality in Europe: A systematic review

Background: Populations differ with respect to their cancer risk and screening preferences, which may influence the performance of colorectal cancer (CRC) screening programs. This review aims to

Evidence for reducing cancer-specific mortality due to screening for breast cancer in Europe: A systematic review

Background: The aim of this study was to quantify the impact of organised mammography screening on breast cancer mortality across European regions. Therefore, a systematic review was performed including different types of studies from all European regions and stringently used clearly defined quality appraisal to summarise the best evidence. Methods: Six databases were searched including Embase, Medline and Web of Science from inception to March 2018. To identify all eligible studies which assessed the effect of organised screening on breast cancer mortality, two reviewers independently applied predefined inclusion and exclusion criteria. Original studies in English with a minimum follow-up of five years that were randomised controlled trials (RCTs) or observational studies were included. The Cochrane risk of bias instrument and the Newcastle–Ottawa Scale were used to assess the risk of bias. Results: Of the 5015 references initially retrieved, 60 were included in the final analysis. Those comprised 36 cohort studies, 17 case–control studies and 7 RCTs. None were from Eastern Europe. The quality of the included studies varied: Nineteen of these studies were of very good or good quality. Of those, the reduction in breast cancer mortality in attenders versus non-attenders ranged between 33% and 43% (Northern Europe), 43%–45% (Southern Europe) and 12%–58% (Western Europe). The estimates ranged between 4% and 31% in invited versus non-invited. Conclusion: This systematic review provides evidence that organised screening reduces breast cancer mortality in all European regions wh

Development and Validation of Three Regional Microsimulation Models for Predicting Colorectal Cancer Screening Benefits in Europe

Background. Validated microsimulation models have been shown to be useful tools in providing support for colorec- tal cancer (CRC) screening decisions. Aiming to assist European countries in reducing CRC mortality, we developed and validated three regional models for evaluating CRC screening in Europe. Methods. Microsimulation Screening Analysis–Colon (MISCAN-Colon) model versions for Italy, Slovenia, and Finland were quantified using data from different national institutions. These models were validated against the best available evidence for the effectiveness of screening from their region (when available): the Screening for COlon REctum (SCORE) trial and the Florentine fecal immunochemical test (FIT) screening study for Italy; the Norwegian Colorectal Cancer Prevention (NORCCAP) trial and the guaiac fecal occult blood test (gFOBT) Finnish population-based study for Finland. When published evidenc

Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems