The evidence base for breast cancer screening

Centre for Research in Evidence-Based Practice, Bond University, Gold Coast, 4229 Australia.
Preventive Medicine (Impact Factor: 3.09). 06/2011; 53(3):100-2. DOI: 10.1016/j.ypmed.2011.05.011
Source: PubMed


The history of breast cancer screening is littered with controversy. With 10 trials spanning 4 decades, we have a substantial body of evidence, but with different aims and flaws. Combined analysis of the intention-to-treat results gives an overall relative reduction in breast cancer mortality of 19% (95% CI 12%-26%), which, if adjusted for non-attendance gives an approximate 25% relative reduction for those who attend screening. However, given that 4% of all-cause mortality is due to breast cancer deaths, this translates into a less than 1% reduction in all-cause mortality. An emerging issue in interpretation is the improvements in treatment since these trials recruited women. Modern systemic therapy would have improved survival (models suggest between 12% and 21%) in both screened and non-screened groups, which would result in a lesser difference in absolute risk reduction from screening but probably a similar, or slightly smaller, relative risk reduction. However benefits and harms, particularly over-diagnosis, need to balanced and differ by age-groups. The informed views of recipients of screening are needed to guide current and future policy on screening.

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    • "mammographic screening are determined by international organizations and differ in every country according to their own standards dependent on screening policies. The randomized controlled trials and observational studies of screening programs have shown the efficacy of mammographic screening in women aged 50-69 years (Glasziou and Houssami, 2011). In almost all countries outside the USA, screening programs start at 50 years of age. "
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    ABSTRACT: Background: The Bahcesehir Breast Cancer Screening Project is the first organized population based breast cancer mammographic screening project in Turkey. The objective of this prospective observational study was to demonstrate the feasibility of a screening program in a developing country and to determine the appropriate age (40 or 50 years old) to start with screening in Turkish women. Materials and methods: Between January 2009 to December 2010, a total of 3,758 women aged 40-69 years were recruited in this prospective study. Screening was conducted biannually, and five rounds were planned. After clinical breast examination (CBE), two-view mammograms were obtained. True positivity, false positivity, positive predictive values (PPV) according to ACR, cancer detection rate, minimal cancer detection rate, axillary node positivity and recall rate were calculated. Breast ultrasound and biopsy were performed in suspicious cases. Results: Breast biopsy was performed in 55 patients, and 18 cancers were detected in the first round. The overall cancer detection rate was 4.8 per 1,000 women. Most of the screened women (54%) and detected cancers (56%) were in women aged 40- 49. Ductal carcinoma in situ (DCIS) and stage I cancer and axillary node positivity rates were 22%, 61%, and 16.6%, respectively. The positive predictivity for biopsy was 32.7%, whereas the overall recall rate was 18.4 %. Conclusions: Preliminary results of the study suggest that population based organized screening are feasible and age of onset of mammographic screening should be 40 years in Turkey.
    Asian Pacific journal of cancer prevention: APJCP 02/2014; 15(4):1693-1697. DOI:10.7314/APJCP.2014.15.4.1693 · 2.51 Impact Factor
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    • "Mammography screening has been shown to reduce breast cancer mortality in overviews of the randomised trials, and both its benefits and harms have been evaluated and debated [1] [2] [3]. Recently, two prospective population-based screening trials [4] [5] have shown that adding digital breast tomosynthesis or 3D-mammography, a derivative mammographic technology [6] [7] [8] [9], to conventional 2D-mammography significantly increases breast cancer detection. "
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    ABSTRACT: Purpose We compared detection measures for breast screening strategies comprising single-reading or double-reading using standard 2D-mammography or 2D/3D-mammography, based on the ‘screening with tomosynthesis or standard mammography’ (STORM) trial. Methods STORM prospectively examined screen-reading in two sequential phases, 2D-mammography alone and integrated 2D/3D-mammography, in asymptomatic women participating in Trento and Verona (Northern Italy) population-based screening services. Outcomes were ascertained from assessment and/or excision histology or follow-up. For each screen-reading strategy we calculated the number of detected and non-detected (including interval) cancers, cancer detection rates (CDRs), false positive recall (FPR) measures and incremental CDR relative to a comparator strategy. We estimated the false:true positive (FP:TP) ratio and sensitivity of each mammography screening strategy. Paired binary data were compared using McNemar’s test. Results Amongst 7292 screening participants, there were 65 (including six interval) breast cancers; estimated first-year interval cancer rate was 0.82/1000 screens (95% confidence interval (CI): 0.30–1.79/1000). For single-reading, 35 cancers were detected at both 2D and 2D/3D-mammography, 20 cancers were detected only with 2D/3D-mammography compared with none at 2D-mammography alone (p < 0.001) and 10 cancers were not detected. For double-reading, 39 cancers were detected at 2D-mammography and 2D/3D-mammography, 20 were detected only with 2D/3D-mammography compared with none detected at 2D-mammography alone (p < 0.001) and six cancers were not detected. The incremental CDR attributable to 2D/3D-mammography (versus 2D-mammography) of 2.7/1000 screens (95% CI: 1.6–4.2) was evident for single and for double-reading. Incremental CDR attributable to double-reading (versus single-reading) of 0.55/1000 screens (95% CI: −0.02–1.4) was evident for 2D-mammography and for 2D/3D-mammography. Estimated FP:TP ratios showed that 2D/3D-mammography screening strategies had more favourable FP to TP trade-off and higher sensitivity, applying single-reading or double-reading, relative to 2D-mammography screening. Conclusion The evidence we report warrants rethinking of breast screening strategies and should be used to inform future evaluations of 2D/3D-mammography that assess whether or not the estimated incremental detection translates into improved screening outcomes such as a reduction in interval cancer rates.
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    • "Women with a mutation in the BRCA1 or BRCA2 gene are at an increased lifetime breast cancer risk and they have a younger mean age at breast cancer diagnosis than that in the general population (mean age of onset: BRCA1, 53.9 years; BRCA2, 58.5 years; general population, 69.5 years) (Easton et al, 1995; Ford et al, 1998; Chen and Parmigiani 2007). These women are therefore offered mammography screening, which, in the general population, is the only screening test associated with reduced breast cancer mortality (Glasziou and Houssami 2011). However, mammography has reduced screening sensitivity in younger age groups (Yankaskas et al, 2010) and in gene mutation carriers (Warner et al, 2008). "
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    ABSTRACT: Background: There is no consensus on the most effective strategy (mammography or magnetic resonance imaging (MRI)) for screening women with BRCA1 or BRCA2 mutations. The effectiveness and cost-effectiveness of the Dutch, UK and US screening strategies, which involve mammography and MRI at different ages and intervals were evaluated in high-risk women with BRCA1 or BRCA2 mutations. Methods: Into a validated simulation screening model, outcomes and cost parameters were integrated from published and cancer registry data. Main outcomes were life-years gained and incremental cost-effectiveness ratios. The simulation was situated in the Netherlands as well as in the United Kingdom, comparing the Dutch, UK and US strategies with the population screening as a reference. A discount rate of 3% was applied to both costs and health benefits. Results: In terms of life-years gained, the strategies from least to most cost-effective were the UK, Dutch and US screening strategy, respectively. However, the differences were small. Applying the US strategy in the Netherlands, the costs were €43 800 and 68 800 for an additional life-year gained for BRCA1 and BRCA2, respectively. At a threshold of €20 000 per life-year gained, implementing the US strategy in the Netherlands has a very low probability of being cost-effective. Stepping back to the less-effective UK strategy would save relatively little in costs and results in life-years lost. When implementing the screening strategies in the United Kingdom, the Dutch, as well as the US screening strategy have a high probability of being cost-effective. Conclusion: From a cost-effectiveness perspective, the Dutch screening strategy is preferred for screening high-risk women in the Netherlands as well as in the United Kingdom.
    British Journal of Cancer 04/2013; 108(8). DOI:10.1038/bjc.2013.149 · 4.84 Impact Factor
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