| 1. |
- Ancelle-Park, R., et al.
(författare)
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Summary of the evidence of breast cancer service screening outcomes in Europe and first estimate of the benefit and harm balance sheet
- 2012
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Ingår i: Journal of Medical Screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 19, s. 5-13
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To construct a European 'balance sheet' of key outcomes of population-based mammographic breast cancer screening, to inform policy-makers, stakeholders and invited women. Methods From the studies reviewed, the primary benefit of screening, breast cancer mortality reduction, was compared with the main harms, over-diagnosis and false-positive screening results (FPRs). Results Pooled estimates of breast cancer mortality reduction among invited women were 25% in incidence-based mortality studies and 31% in case-control studies (38% and 48% among women actually screened). Estimates of over-diagnosis ranged from 1% to 10% of the expected incidence in the absence of screening. The combined estimate of over-diagnosis for screened women, from European studies correctly adjusted for lead time and underlying trend, was 6.5%. For women undergoing 10 biennial screening tests, the estimated cumulative risk of a FPR followed by non-invasive assessment was 17%, and 3% having an invasive assessment. For every 1000 women screened biennially from age 50-51 until age 68-69 and followed up to age 79, an estimated seven to nine lives are saved, four cases are over-diagnosed, 170 women have at least one recall followed by non-invasive assessment with a negative result and 30 women have at least one recall followed by invasive procedures yielding a negative result. Conclusions The chance of saving a woman's life by population-based mammographic screening of appropriate quality is greater than that of over-diagnosis. Service screening in Europe achieves a mortality benefit at least as great as the randomized controlled trials. These outcomes should be communicated to women offered service screening in Europe.
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| 2. |
- Bjurstam, Nils, et al.
(författare)
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Updated results of the Gothenburg Trial of Mammographic Screening
- 2016
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Ingår i: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 122:12, s. 1832-1835
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUNDThere remain uncertainties about age-specific effects of breast cancer screening on mortality due to the disease. METHODSIn 1982, a randomized trial of mammographic screening every 18 months was started in Gothenburg, Sweden. Women between the ages of 39 and 49 years were randomized to an invitation to screening (intervention group; n = 11,792) or to usual care (the control group; n = 14,321). The corresponding numbers for women between the ages of 50 and 59 years were 10,112 and 15,997. Follow-up data for breast cancer mortality were available up to the end of 2007. Data were analyzed by Poisson regression with conservative variance estimates. RESULTSThere were 79 breast cancer deaths in the intervention arm and 156 in the control arm, and this meant a significant 30% reduction in breast cancer mortality with the offer of screening (relative risk [RR], 0.70; 95% confidence interval [CI], 0.53-0.93; P = .01). In women aged 39 to 49 years, there was a significant 40% reduction in breast cancer mortality (RR, 0.60; 95% CI, 0.43-0.85; P = .003). In the 50- to 59-year age group, there was a nonsignificant 18% breast cancer mortality reduction (RR, 0.82; 95% CI, 0.54-1.26; P = .4). CONCLUSIONSThe policy of offering mammographic screening substantially reduces breast cancer mortality and can do so in women younger than 50 years. Cancer 2016;122:1832-5. (c) 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. In a randomized trial of breast cancer screening, a significant reduction in breast cancer mortality is found with the offer of mammographic screening. The results suggest that screening can be effective in women younger than 50 years. and distribution in any medium, provided the original work is properly cited, the use is non- commercial and no modifications or adaptations are made.
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| 3. |
- Duffy, S W, et al.
(författare)
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Complexities in the estimation of overdiagnosis in breast cancer screening.
- 2008
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 1532-1827 .- 0007-0920. ; 99:7, s. 1176-1178
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Tidskriftsartikel (refereegranskat)abstract
- There is interest in estimating and attributing temporal changes in incidence of breast cancer in relation to the initiation of screening programmes, in particular to estimation of overdiagnosis of breast cancer as a result of screening. In this paper, we show how screening introduces complexities of analysis and interpretation of incidence data. For example, lead time brings forward time- and age-related increases in incidence. In addition, risk factors such as hormone replacement therapy use have been changing contemporaneously with the introduction of screening. Although we do not indicate exactly how such complexities should be corrected for, we use some simple informal adjustments to show how they may account for a substantial proportion of increased incidence, which might otherwise erroneously have been attributed to overdiagnosis. We illustrate this using an example of analysis of breast cancer incidence data from Sweden.
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| 4. |
- Duffy, S. W., et al.
(författare)
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Overdiagnosis and overtreatment of breast cancer: estimates of overdiagnosis from two trials of mammographic screening for breast cancer
- 2005
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Ingår i: Breast Cancer Res. - 1465-542X. ; 7:6, s. 258-65
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Tidskriftsartikel (refereegranskat)abstract
- Randomised controlled trials have shown that the policy of mammographic screening confers a substantial and significant reduction in breast cancer mortality. This has often been accompanied, however, by an increase in breast cancer incidence, particularly during the early years of a screening programme, which has led to concerns about overdiagnosis, that is to say, the diagnosis of disease that, if left undetected and therefore untreated, would not become symptomatic. We used incidence data from two randomised controlled trials of mammographic screening, the Swedish Two-county Trial and the Gothenburg Trial, to establish the timing and magnitude of any excess incidence of invasive disease and ductal carcinoma in situ (DCIS) in the study groups, to ascertain whether the excess incidence of DCIS reported early in a screening trial is balanced by a later deficit in invasive disease and provide explicit estimates of the rate of 'real' and non-progressive 'overdiagnosed' tumours from the study groups of the trials. We used a multistate model for overdiagnosis and used Markov Chain Monte Carlo methods to estimate the parameters. After taking into account the effect of lead time, we estimated that less than 5% of cases diagnosed at prevalence screen and less than 1% of cases diagnosed at incidence screens are being overdiagnosed. Overall, we estimate overdiagnosis to be around 1% of all cases diagnosed in screened populations. These estimates are, however, subject to considerable uncertainty. Our results suggest that overdiagnosis in mammography screening is a minor phenomenon, but further studies with very large numbers are required for more precise estimation.
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| 5. |
- Duffy, S.W., et al.
(författare)
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The Swedish two-county trial of mammographic screening : Cluster randomisation and end point evaluation
- 2003
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 14:8, s. 1196-1198
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Swedish Two-County Trial has been criticised on the grounds of the cluster randomisation and alleged bias in classification of cause of death. Patients and methods: In the Two-County Trial, 77080 women were randomised to regular invitation to screening (active study population, ASP) and 55985 to no invitation (passive study population, PSP), in 45 geographical clusters. After ~7 years, the PSP was invited to screening and the trial closed. We analysed data using hierarchical statistical models to take account of cluster randomisation, and performed a conservative analysis assuming a systematic difference between ASP and PSP in baseline breast cancer mortality in one of the counties. We also analysed deaths from causes other than breast cancer and from all causes among breast cancer cases diagnosed in the ASP and PSP. Results: Taking account of the cluster randomisation there was a significant 30% reduction in breast cancer mortality in the ASP. Conservatively, assuming a systematic difference between ASP and PSP clusters in baseline breast cancer mortality, there was a significant 27% reduction in mortality in the ASP. Ignoring classification of cause of death, there was a significant 13% reduction in all-cause mortality in breast cancer cases in the ASP. Conclusions: Breast cancer mortality is a valid end point and mammographic screening does indeed reduce mortality from breast cancer. The criticisms of the Swedish Two-County Trial are unfounded.
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| 6. |
- Duffy, S.W., et al.
(författare)
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Tumor size and breast cancer detection : What might be the effect of a less sensitive screening tool than mammography?
- 2006
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Ingår i: The Breast Journal. - 1075-122X .- 1524-4741. ; 12:SUPPL. 1
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Tidskriftsartikel (refereegranskat)abstract
- In some limited-resource areas, a state-of-the-art mammography program is not affordable. In such circumstances, one might consider a less resource-intensive, but also less sensitive screening tool such as clinical breast examination (CBE). We used data from the Swedish Two-County Trial to estimate the shift in tumor size resulting from invitation to mammographic screening. By postulating a lesser benefit of a less sensitive screening tool (CBE), particularly in terms of detecting very small tumors, we predicted its likely effect on tumor size distribution. In addition, using the observed association between tumor size and nodal status, and between tumor size and fatality, we predicted the likely benefit in terms of reductions in node-positive disease and in breast cancer mortality. An invitation to mammographic screening was associated with a 27% reduction in the number of node-positive tumors and a 31% reduction in the number of breast cancer deaths. We estimate that in the trial population, screening with CBE alone would have led to an 11% reduction in node-positive tumors and an 11% reduction in breast cancer deaths (approximately 42 deaths prevented per 1000 cases). Assuming instead a tumor size distribution typical of a limited-resource setting (70% of tumors are 30 mm at presentation), we estimate that screening with CBE alone would lead to a 13% reduction in node-positive tumors and a 12% reduction in breast cancer deaths (approximately 72 deaths prevented per 1000 cases). Thus, although the relative benefit of CBE is only slightly greater in the limited-resource setting, the absolute reduction in deaths per case is about 70% higher. Our findings suggest that a less sensitive tool might be expected to confer a breast cancer mortality reduction about half of that observed with mammography. © 2006 The Fred Hutchinson Cancer Research Center.
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| 7. |
- Holmberg, Lars, et al.
(författare)
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Differences in endpoints between the Swedish W-E (two county) trial of mammographic screening and the Swedish overview : methodological consequences
- 2009
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Ingår i: Journal of Medical Screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 16:2, s. 73-80
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To characterize and quantify the differences in the number of cases and breast cancer deaths in the Swedish W-E Trial compared with the Swedish Overview Committee (OVC) summaries and to study methodological issues related to trials in secondary prevention. SETTING: The study population of the W-E Trial of mammography screening was included in the first (W and E county) and the second (E-county) OVC summary of all Swedish randomized mammography screening trials. The OVC and the W-E Trial used different criteria for case definition and causes of death determination. METHOD: A Review Committee compared the original data files from W and E county and the first and second OVC. The reason for a discrepancy was determined individually for all non-concordant cases or breast cancer deaths. RESULTS: Of the 2615 cases included by the W-E Trial or the OVC, there were 478 (18%) disagreements. Of the disagreements 82% were due to inclusion/exclusion criteria, and 18% to disagreement with respect to cause of death or vital status at ascertainment. For E-County, the OVC inclusion rules and register based determination of cause of death (second OVC) rather than individual case review (W-E Trial and 1st OVC) resulted in a reduction of the estimate of the effect of screening, but for W-County the difference between the original trial and the OVC was modest. CONCLUSIONS: The conclusion that invitation to mammography screening reduces breast cancer mortality remains robust. Disagreements were mainly due to study design issues, while disagreements about cause of death were a minority. When secondary research does not adhere to the protocols of the primary research projects, the consequences of such design differences should be investigated and reported. Register linkage of trials can add follow-up information. The precision of trials with modest size is enhanced by individual monitoring of case status and outcome status such as determination of cause of death.
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| 8. |
- Paci, E., et al.
(författare)
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European Breast Cancer Service Screening Outcomes : A First Balance Sheet of the Benefits and Harms
- 2014
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research. - 1055-9965 .- 1538-7755. ; 23:7, s. 1159-1163
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Tidskriftsartikel (refereegranskat)abstract
- A recent comprehensive review has been carried out to quantify the benefits and harms of the European population-based mammographic screening programs. Five literature reviews were conducted on the basis of the observational published studies evaluating breast cancer mortality reduction, breast cancer overdiagnosis, and false-positive results. On the basis of the studies reviewed, the authors present a first estimate of the benefit and harm balance sheet. For every 1,000 women screened biennially from ages 50 to 51 years until ages 68 to 69 years and followed up until age 79 years, an estimated seven to nine breast cancer deaths are avoided, four cases are overdiagnosed, 170 women have at least one recall followed by noninvasive assessment with a negative result, and 30 women have at least one recall followed by invasive procedures yielding a negative result. The chance of a breast cancer death being avoided by population-based mammography screening of appropriate quality is more than that of overdiagnosis by screening. These outcomes should be communicated to women offered service screening in Europe.
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| 9. |
- Tabar, L., et al.
(författare)
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All-cause mortality among breast cancer patients in a screening trial : Support for breast cancer mortality as an end point
- 2002
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Ingår i: Journal of Medical Screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 9:4, s. 159-162
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Tidskriftsartikel (refereegranskat)abstract
- Background: It has recently been suggested that all-cause mortality is a more appropriate end point than disease specific mortality in cancer screening trials, and that disease specific mortality is biased in favour of screening. This suggestion is based partly on supposed inconsistencies between all-cause mortality results and disease specific results in cancer screening trials, and alleged increases in deaths from causes other than breast cancer among breast cancer cases diagnosed among women invited to screening. Methods: We used data from the Swedish Two-County Trial of mammographic screening for breast cancer, in which 77 080 women were randomised to an invitation to screening and 55 985 to no invitation. We estimated relative risks (RRs) (invited v control) of death from breast cancer, death from other causes within the breast cancer cases, and death from all causes within the breast cancer cases. RRs were adjusted for age and took account of the longer follow up of breast cancer cases in the invited group due to lead time. Results: There was a significant 31% reduction in breast cancer mortality in the invited group (RR 0.69, 95% confidence interval (Cl) 0.58-0.80, p
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| 10. |
- Tabar, L., et al.
(författare)
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Number needed to screen : Lives saved over 20 years of follow-up in mammographic screening
- 2004
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Ingår i: Journal of Medical Screening. - : SAGE Publications. - 0969-1413 .- 1475-5793. ; 11:3, s. 126-129
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To estimate the number needed to screen with mammography to save one life, based on a stated amount of screening activity and long-term follow-up for breast cancer death. Setting: A randomised controlled trial of mammographic screening for breast cancer, with 77,080 women invited to screening and 55,985 not invited. The invited group was offered screening for seven years. Follow-up continued for a total of just over 20 years. Methods: Number needed to screen for seven years to save one life over 20 years was calculated by dividing the number screened (not the number invited) by the total number of lives saved. Similarly, we calculated the number of mammographic examinations required to save one life. Results: We estimate that the number of women needed to screen for seven years to save one life over 20 years is 465 (95% CI 324-819). The number of mammographic examinations needed to save one life was 1499 (95% CI 1046-2642). Conclusions: The number needed to screen to save one life is smaller than has been reported in the past. Mammographic screening is effective in absolute terms as well as relative. Long-term follow-up allowed us to estimate the absolute benefit with greater accuracy.
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