Breast Cancer Detection with an Ensemble of Deep Learning Networks Using a Consensus-Adaptive Weighting Method

Breast cancer's high mortality rate is often linked to late diagnosis, with mammograms as key but sometimes limited tools in early detection. To enhance diagnostic accuracy and speed, this study introduces a novel computer-aided detection (CAD) ensemble system. This system incorporates advanced deep learning networks-EfficientNet, Xception, MobileNetV2, InceptionV3, and Resnet50-integrated via our innovative consensus-adaptive weighting (CAW) method. This method permits the dynamic adjustment of multiple deep networks, bolstering the system's detection capabilities. Our approach also addresses a major challenge in pixel-level data annotation of faster R-CNNs, highlighted in a prominent previous study. Evaluations on various datasets, including the cropped DDSM (Digital Database for Screening Mammography), DDSM, and INbreast, demonstrated the system's superior performance. In particular, our CAD system showed marked improvement on the cropped DDSM dataset, enhancing detection rates by approximately 1.59% and achieving an accuracy of 95.48%. This innovative system represents a significant advancement in early breast cancer detection, offering the potential for more precise and timely diagnosis, ultimately fostering improved patient outcomes.

Interpreting Breast Cancer Mortality Trends Related to Introduction of Mammography Screening: A Simulation Study

Background. Several studies have evaluated the effect of mammography screening on breast cancer mortality based on overall breast cancer mortality trends, with varied conclusions. The statistical power of such trend analyses is, however, not carefully studied. Methods. We estimated how the effect of screening on overall breast cancer mortality is likely to unfold. Because a screening effect is based on earlier treatment, screening can affect only new incident cases after screening introduction. To evaluate the likelihood of detecting screening effects on overall breast cancer mortality time trends, we calculated the statistical power of joinpoint regression analysis on breast cancer mortality trends around screening introduction using simulations. Results. We found that a very gradual increase in population-level screening effect is expected due to prescreening incident cases. Assuming 25% effectiveness of a biennial screening program in reducing breast cancer mortality among women 50 to 69 y of age, the expected reduction in overall breast cancer mortality was 3% after 2 y and reached a long-term effect of 18% after 20 y. In common settings, the statistical power to detect any screening effects using joinpoint regression analysis is very low (<50%), even in an artificial setting of constant risk of baseline breast cancer mortality over time. Conclusions. Population effects of screening on breast cancer mortality emerge very gradually and are expected to be considerably lower than the effects reported in trials excluding women diagnosed before screening. Studies of overall breast cancer mortality time trends have too low statistical power to reliably detect screening effects in most populations. Implications. Researchers and policy makers evaluating mammography screening should avoid using breast cancer mortality trend analysis that does not separate pre- and postscreening incident cases.

HIGHLIGHTS

Population-level mammography screening effects on breast cancer mortality emerge gradually following screening introduction, resulting in very low statistical power of trend analysis.Researchers and policy makers evaluating mammography screening should avoid relying on population-wide breast cancer mortality trends.Expected mammography screening effects at population level are lower than those from screening trials, as many cases of breast cancer fall outside the screening age range.

How a faecal immunochemical test screening programme changes annual colorectal cancer incidence rates: an Italian intention-to-screen study

Background

This study aimed to evaluate the effectiveness of a biennial faecal immunochemical test (FIT) screening programme in reducing annual colorectal cancer (CRC) incidence in its dynamic target population.

Methods

The target population included over 1,000,000 persons aged 50–69 living in a region of northern Italy. The average annual response rate to invitation was 51.4%. Each observed annual age-standardised (Europe) rate per 100,000 persons between 2005, the year of introduction of the programme, and 2016 was compared with each expected annual rate as estimated with age-period-cohort (men) and age-period (women) models.

Results

For both sexes, the rates observed in 1997–2004 and those expected in 2005–2016 were stable. Observed rates increased in 2005, peaked in 2006 (the first full year of screening), dropped significantly below the expected level in 2009, and continued to decrease until 2013 (the eighth full year), after which no further significant changes occurred. In the pooled years 2013–2016, the observed incidence rate per 100,000 persons was 102.2 [95% CI: 97.4, 107.1] for men, 75.6 [95% CI: 71.6, 79.7] for women and 88.4 [95% CI: 85.3, 91.5] for both sexes combined, with an observed:expected incidence rate ratio of 0.68 [95% CI: 0.65, 0.71], 0.79 [95% CI: 0.76, 0.82] and 0.72 [95% CI: 0.66, 0.81], respectively.

Discussion

The study provided multiple consistent proofs of a causal relationship between the introduction of screening and a stable 28% decrease in annual CRC incidence after eight years.

Breast Cancer Screening Recommendations Inclusive of All Women at Average Risk: Update from the ACR and Society of Breast Imaging

Breast cancer remains the most common nonskin cancer, the second leading cause of cancer deaths, and the leading cause of premature death in US women. Mammography screening has been proven effective in reducing breast cancer deaths in women age 40 years and older. A mortality reduction of 40% is possible with regular screening. Treatment advances cannot overcome the disadvantage of being diagnosed with an advanced-stage tumor. The ACR and Society of Breast Imaging recommend annual mammography screening beginning at age 40, which provides the greatest mortality reduction, diagnosis at earlier stage, better surgical options, and more effective chemotherapy. Annual screening results in more screening-detected tumors, tumors of smaller sizes, and fewer interval cancers than longer screening intervals. Screened women in their 40s are more likely to have early-stage disease, negative lymph nodes, and smaller tumors than unscreened women. Delaying screening until age 45 or 50 will result in an unnecessary loss of life to breast cancer and adversely affects minority women in particular. Screening should continue past age 74 years, without an upper age limit unless severe comorbidities limit life expectancy. Benefits of screening should be considered along with the possibilities of recall for additional imaging and benign biopsy and the less tangible risks of anxiety and overdiagnosis. Although recall and biopsy recommendations are higher with more frequent screening, so are life-years gained and breast cancer deaths averted. Women who wish to maximize benefit will choose annual screening starting at age 40 years and will not stop screening prematurely.

Breast cancer screening adherence rates and barriers of implementation in ethnic, cultural and religious minorities: A systematic review

Breast cancer is the most common cancer affecting women worldwide. Adherence to breast cancer screening guidelines is frequently lower in racial, ethnic and cultural minority populations and is affected by potential inequities or barriers to screening that these minorities face. Therefore, the aim of the present study was to collect information from different minority groups worldwide, assess adherence to breast cancer screening and evaluate barriers or limitations causing non-adherence, which should facilitate the development of effective interventions. A search was conducted through PubMed and Web of Science. Studies were considered as eligible if they met the following criteria: i) Female patients; ii) breast cancer screening program implemented in the country; iii) minority groups; iv) asymptomatic; v) report written in Portuguese or English; vi) study published from 2015 onwards. The Critical Appraisal Skills Programme checklist was used for qualitative studies and the Strengthening The Reporting of Observational Studies in Epidemiology checklist for cross-sectional studies. From the 348 initial articles, 86 were removed due to duplication and 19 were selected, analyzed and summarized, accordingly. Of the 19 studies included, 5.3% were classified as high quality, 52.6% as moderate to high and 42.1% as moderate. A total of 15 studies were cross-sectional and 4 were qualitative, collectively including 250,733 women. The rate of adherence to mammogram in different minorities was evaluated, obtaining a mean value of 49.7% in the last 2 years, and statistically significant barriers were selected and divided into sociodemographic; personal; ethnic, cultural and religious; and external factors. The characteristics of each population play a major role in the population's breast health practices. If the population, adherence rates, barriers and inequities are carefully studied, screening models may be customized and participation to breast cancer screening can be optimized, thereby reducing the high breast cancer-associated mortality.

Breast Cancer Mortality After Implementation of Organized Population-Based Breast Cancer Screening in Norway

BACKGROUND

We estimated breast cancer (BC) mortality reduction associated with invitations to a nationwide population-based screening program and with changes in treatment.

MATERIALS AND METHODS

BreastScreen Norway started in 1996 and became nationwide in 2005. It invites women aged 50-69 years to biennial mammographic screening. We retrieved individual-level data for 1 340 333 women from national registries. During 1996-2014 (screening window), women contributed person-years in noninvited and invited periods. We created comparable periods for 1977-1995 (prescreening window) by dividing the follow-up time for each woman into pseudo-noninvited and pseudo-invited periods. We estimated BC mortality for the four periods, using the so-called evaluation model: counting BC deaths in each period for all women diagnosed within the period and counting BC deaths and person-years after screening-age for those diagnosed within screening age. We used a multivariable flexible parametric survival model to estimate hazard ratio (HR) for the effect of invitation and improved treatment.

RESULTS

Using the regression approach, we found 5818 BC deaths across 16 533 281 person-years. Invitations to screening reduced BC mortality by 20% (HR = 0.80, 95% confidence interval [CI] = 0.70 to 0.91) among women 50 years and older and by 25% (HR = 0.75, 95% CI = 0.65 to 0.86) among screening-aged women. The treatment effect was 23% (HR = 0.77, 95% CI = 0.65 to 0.92) for women 50 years and older and 17% (HR = 0.83, 95% CI = 0.74 to 0.94) for screening-aged women.

CONCLUSION

We observed a similar reduction in BC mortality associated with invitations to screening and improvements in treatment during 1977-2014, among women 50 years and older.

Breast cancer screening program in Lithuania: trends in breast cancer mortality before and during the introduction of the mammography screening programme

Abstract. Background.

Breast cancer is the most frequent oncological disease as well as the leading cause of cancer death among women worldwide. Decline in mortality in economically strong countries is observed. This decline is mostly related to early diagnosis (an improvement in breast cancer awareness and the mammography screening program (MSP)) and a more effective treatment. In the end of 2005, MSP started in Lithuania. The main aim of this article is to evaluate the breast cancer mortality during 22 years in Lithuania, as well as changes before the start of the MSP and during its implementation, in order to assess the influence of the MSP on mortality.

Materials and methods.

Analysis is based on data from the population-based Lithuanian Cancer Registry. Analysis of changes in mortality includes the period from 1998 to 2019. Age standardized mortality rates are calculated for assessment of changes. Joinpoint regression analysis is used.

Results.

Applying the segmental regression model, it was found that during the study period mortality was statistically significantly decreasing by -1.1% each year. Mortality among women under the age of 50 decreased both before and during the implementation of MSP. Mortality in the target population also was already decreasing until the implementation of the program, but a significant reduction in mortality was observed in this group since 2006.

Conclusions.

Overall breast cancer mortality is decreasing in Lithuania. After the implementation of MSP the largest reduction in mortality was observed in the target population, however, it is not as pronounced as it could be with the well-organized MSP.

Five-year relative survival by stage of breast and colon cancers in Italy

OBJECTIVE

To present the changes in 5-year relative survival of patients with breast and colorectal cancer in a northern Italian province in the 2000-2012 period. Changes are presented in relation to stage, period, and age in the screening population.

METHODS

A total of 5073 breast cancer and 4093 colorectal cancer cases were registered. Breast cancer was divided into 5 age groups: <45, 45-49, 50-69, 70-74 (the target screening population is ages 45-74), and >74 years. Colorectal cancers were classified into 3 age groups: <50, 50-69 (screening target population), and >69 years. Survival was analysed by stage, period, and screening program.

RESULTS

Five-year breast cancer relative survival was 92.9% overall, with 100%, 91.9%, 78.8%, 34.2%, and 76.4% for stages I, II, III, IV, and unknown, respectively. Survival increased from 89.7%, 91.8%, and 93.4%, respectively, in the periods 2000-2005, 2006-2009, and 2010-2012. Breast cancer survival was stable in early stages (although already high); a slight improvement was seen for stages III and IV. Five-year colorectal cancer relative survival was 63.6% overall, with 93.3%, 78.6%, 69.8%, 13.2%, and 55.8% for stages I, II, III, IV, and unknown, respectively. No improvement in survival was seen in the periods analysed, although the introduction of screening in 2005 did lead to a sharp decrease in incidence and mortality.

CONCLUSIONS

For breast cancer, extending the screening target age led to an improvement in survival; for colorectal cancer, the best impact was on incidence and mortality rate.

The potential of breast cancer screening in Europe

Currently, all European countries offer some form of breast cancer screening. Nevertheless, disparities exist in the status of implementation, attendance and the extent of opportunistic screening. As a result, breast cancer screening has not yet reached its full potential. We examined how many breast cancer deaths could be prevented if all European countries would biennially screen all women aged 50 to 69 for breast cancer. We calculated the number of breast cancer deaths already prevented due to screening as well as the number of breast cancer deaths which could be additionally prevented if the total examination coverage (organised plus opportunistic) would reach 100%. The calculations are based on total examination coverage in women aged 50 to 69, the annual number of breast cancer deaths for women aged 50 to 74 and the maximal possible mortality reduction from breast cancer, assuming similar effectiveness of organised and opportunistic screening. The total examination coverage ranged from 49% (East), 62% (West), 64% (North) to 69% (South). Yearly 21 680 breast cancer deaths have already been prevented due to mammography screening. If all countries would reach 100% examination coverage, 12 434 additional breast cancer deaths could be prevented annually, with the biggest potential in Eastern Europe. With maximum coverage, 23% of their breast cancer deaths could be additionally prevented, while in Western Europe it could be 21%, in Southern Europe 15% and in Northern Europe 9%. Our study illustrates that by further optimising screening coverage, the number of breast cancer deaths in Europe can be lowered substantially.

Geographic Inequalities in Breast Cancer in Italy: Trend Analysis of Mortality and Risk Factors

We calculated time trends of standardised mortality rates and risk factors for breast cancer (BC) from 1990 to 2016 for all women resident in Italy. The age-standardised mortality rate in Italy decreased from 4.2 in 1990 to 3.2 (×100,000) in 2016. While participation in organised screening programmes and age-standardised fertility rates decreased in Italy, screening invitation coverage and mammography uptake, the prevalence of women who breastfed and mean age at birth increased. Although southern regions had favourable prevalence of protective risk factors in the 1990s, fertility rates decreased in southern regions and increased in northern regions, which in 2016 had a higher rate (1.28 vs. 1.32 child per woman) and a smaller increase in women who breastfed (+4% vs. +30%). In 2000, mammography screening uptake was lower in southern than in northern and central regions (28% vs. 52%). However, the increase in mammography uptake was higher in southern (203%) than in northern and central Italy (80%), reducing the gap. Participation in mammographic screening programmes decreased in southern Italy (−10%) but increased in the North (6.6%). Geographic differences in mortality and risk factor prevalence is diminishing, with the South losing all of its historical advantage in breast cancer mortality.

A review of optical breast imaging: Multi-modality systems for breast cancer diagnosis

This review of optical breast imaging describes basic physical and system principles and summarizes technological evolution with a focus on multi-modality platforms and recent clinical trial results. Ultrasound-guided diffuse optical tomography and co-registered ultrasound and photoacoustic imaging systems are emphasized as models of state of the art optical technology that are most conducive to clinical translation.

Deep Neural Networks With Region-Based Pooling Structures for Mammographic Image Classification

Breast cancer is one of the most frequently diagnosed solid cancers. Mammography is the most commonly used screening technology for detecting breast cancer. Traditional machine learning methods of mammographic image classification or segmentation using manual features require a great quantity of manual segmentation annotation data to train the model and test the results. But manual labeling is expensive, time-consuming, and laborious, and greatly increases the cost of system construction. To reduce this cost and the workload of radiologists, an end-to-end full-image mammogram classification method based on deep neural networks was proposed for classifier building, which can be constructed without bounding boxes or mask ground truth label of training data. The only label required in this method is the classification of mammographic images, which can be relatively easy to collect from diagnostic reports. Because breast lesions usually take up a fraction of the total area visualized in the mammographic image, we propose different pooling structures for convolutional neural networks(CNNs) instead of the common pooling methods, which divide the image into regions and select the few with high probability of malignancy as the representation of the whole mammographic image. The proposed pooling structures can be applied on most CNN-based models, which may greatly improve the models' performance on mammographic image data with the same input. Experimental results on the publicly available INbreast dataset and CBIS dataset indicate that the proposed pooling structures perform satisfactorily on mammographic image data compared with previous state-of-the-art mammographic image classifiers and detection algorithm using segmentation annotations.

Worldwide Review and Meta-Analysis of Cohort Studies Measuring the Effect of Mammography Screening Programmes on Incidence-Based Breast Cancer Mortality

In 2012, the Euroscreen project published a review of incidence-based mortality evaluations of breast cancer screening programmes. In this paper, we update this review to October 2019 and expand its scope from Europe to worldwide. We carried out a systematic review of incidence-based mortality studies of breast cancer screening programmes, and a meta-analysis of the estimated effects of both invitation to screening and attendance at screening, with adjustment for self-selection bias, on incidence-based mortality from breast cancer. We found 27 valid studies. The results of the meta-analysis showed a significant 22% reduction in breast cancer mortality with invitation to screening, with a relative risk of 0.78 (95% CI 0.75-0.82), and a significant 33% reduction with actual attendance at screening (RR 0.67, 95% CI 0.61-0.75). Breast cancer screening in the routine healthcare setting continues to confer a substantial reduction in mortality from breast cancer.

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 where screening was implemented and monitored, while quantification is still lacking for Eastern Europe. The wide range of estimates indicates large differences in the evaluation designs between studies, rather than in the effectiveness of screening.

Dissemination of health technologies: Trends in the use of diagnostic test in breast cancer screening

OBJECTIVE

To analyse trends in the use of diagnostic test in breast cancer screening programs in Spain.

MATERIALS AND METHODS

Retrospective study of 542,695 women who had undergone at least one screening mammogram in any of the screening centres of three administrative regions in Spain, between 1996 and 2011. Process measures were: overall recall rate, overall invasive test rate, and rates of each type of invasive test (fine-needle aspiration biopsy, core-needle biopsy and surgical biopsy). As results measures were included detection of benign lesions rate, ductal in situ cancer rate and invasive cancer rate. Adjusted by age rates were estimated year by year for each measure and, also, the annual percent of change and its corresponding joint points.

RESULTS

Core-needle biopsy rates decreased between 1996 and 1999 and changed trends in 1999-2011 with an increase of 4.9% per year. Overall recall rate declined by 4.6% from 1999 to 2004, invasive test rate declined between 1996 and 2004 by 24.3%. Fine-needle aspiration biopsy rate changes were: a 22.4% declined per year (1996-1998), and 13.5% declined per year (1998-2005). Benign lesions rate decreased from 1996 to 2011, 21.4% per year (1996-2001) and 6.0% (2001-2011). Ductal carcinoma in situ and invasive cancer had no-statistically significant changes.

CONCLUSION

The introduction of core-needle biopsy was slow and not concurrent with the reduction in the use of other diagnostic tests, but also represented a reduction in the rate of overall diagnostic tests and in the detection rate of benigns lesions without affecting the cancer detection rates.

The role of digital breast tomosynthesis in breast cancer screening: a manufacturer- and metrics-specific analysis

Aim

Digital Breast Tomosynthesis (DBT), with or without Digital Mammography (DM) or Synthetic Mammography (SM), has been introduced or is under consideration for its introduction in breast cancer screening in several countries, as it has been shown that it has advantages over DM. Despite this there is no agreement on how to implement DBT in screening, and in many cases there is a lack of official guidance on the optimum usage of each commercially available system. The aim of this review is to carry out a manufacturer-specific summary of studies on the implementation of DBT in breast cancer screening.

Methods

An exhaustive literature review was undertaken to identify clinical observer studies that evaluated at least one of five common metrics: sensitivity, specificity, area under the curve (AUC) of the receiver-operating characteristics (ROC) analysis, recall rate and cancer detection rate. Four common DBT implementation methods were discussed in this review: (1) DBT, (2) DM with DBT, (3) 1-view DBT with or without 1-view DM or 2-view DM and (4) DBT with SM.

Results

A summary of 89 studies, selected from a database of 677 studies, on the assessment of the implementation of DBT in breast cancer screening is presented in tables and discussed in a manufacturer- and metric-specific approach. Much more studies were carried out using some DBT systems than others. For one implementation method of DBT by one manufacturer there is a shortage of studies, for another implementation there are conflicting results. In some cases, there is a strong agreement between studies, making the advantages and disadvantages of each system clear.

Conclusion

The optimum implementation method of DBT in breast screening, in terms of diagnostic benefit and patient radiation dose, for one manufacturer does not necessarily apply to other manufacturers.

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 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.

Development of breast cancer mortality considering the implementation of mammography screening programs - a comparison of western European countries

Background

Triggered by the successive implementation of organized mammography screening programs (MSPs) throughout western European countries over the last decades, there is an ongoing debate questioning their effectiveness. Since it is difficult to assess the effect of MSPs on a population level, we rather aim to assess the impact of the implementation itself on breast cancer mortality rates utilizing an ecological study design.

Methods

We analyzed age group-specific (50–59, 60–69 and 70–79 years) female breast cancer mortality rates in 14 western European countries between 1980 and 2017 using Joinpoint regression, interrupted time series (ITS) regression and multivariable Poisson regression.

Results

The Joinpoint analysis demonstrated decreasing trends resulting in annual percentage changes ranging from − 1.5% to − 5.4% (50–59), − 0.2% to − 8.1% (60–69) and 0% to − 7.1% (70–79) depending on the country within 3 years after MSP implementation. The ITS analysis results in highly significant interaction terms (calendar year * binary MSP indicator) for all age groups. The multivariable regression using “calendar year”, “year of MSP implementation” and “years with MSP” as independent variables yielded a significant yearly decrease for “years with MSP” ranging from 0.9 to 1.2%.

Conclusions

The results of this study suggest a positive association between the implementation of MSPs and the (accelerated) reduction of breast cancer mortality rates. Measuring and quantifying the isolated effect of MSPs on a population level will require additional studies using individual data.

Cancer screening in the United States, 2019: A review of current American Cancer Society guidelines and current issues in cancer screening

Each year, the American Cancer Society publishes a summary of its guidelines for early cancer detection, data and trends in cancer screening rates, and select issues related to cancer screening. In this issue of the journal, the current American Cancer Society cancer screening guidelines are summarized, and the most current data from the National Health Interview Survey are provided on the utilization of cancer screening for men and women and on the adherence of men and women to multiple recommended screening tests.

Estimating the impact of an organised screening programme on cervical cancer incidence: A 26-year study from northern Italy

The impact of the organised cervical cancer (CC) screening programmes implemented in Europe since the 1990s has been insufficiently evaluated. We investigated the changes in CC incidence following the introduction of a screening programme in the Emilia-Romagna Region (northern Italy). The study period was 1988-2013. The programme, targeting women aged 25-64 years (1,219,000 in 2018), started in 1998. The annual incidence rates that would be expected in 1998-2013 in the absence of screening were estimated, first, by analysing the annual rates in 1988-1997 with a log-linear model and, second, by analysing the annual rates in 1988-2013 with an age-period model in which the period effect was enforced to be linear. Cervical adenocarcinoma incidence trend over the entire period was used to validate both estimates. Observed annual rates were compared to the two series of expected ones with the incidence rate ratio (IRR). Incidence remained stable during 1988-1997, peaked in 1998 and then decreased until 2007, when it stabilised. The two series of expected rates were virtually coincident and their trends roughly paralleled the stable adenocarcinoma incidence trend. After 2007, the median IRR was 0.60 (95% confidence interval, 0.45-0.81) based on the log-linear model and 0.58 (95% confidence interval, 0.34-0.97) based on the age-period model. Thirty-six to seventy-five CC cases were prevented annually for an average annual frequency of 6.5 per 100,000 women in the target population. In summary, consistent circumstantial evidences were obtained that the organised screening programme brought about a 40% reduction in annual CC incidence after 10 years.

The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening

Background

Women and their health care providers need a reliable answer to this important question: If a woman chooses to participate in regular mammography screening, then how much will this choice improve her chances of avoiding a death from breast cancer compared with women who choose not to participate?

Methods

To answer this question, we used comprehensive registries for population, screening history, breast cancer incidence, and disease‐specific death data in a defined population in Dalarna County, Sweden. The annual incidence of breast cancer was calculated along with the annual incidence of breast cancers that were fatal within 10 and within 11 to 20 years of diagnosis among women aged 40 to 69 years who either did or did not participate in mammography screening during a 39‐year period (1977‐2015). For an additional comparison, corresponding data are presented from 19 years of the prescreening period (1958‐1976). All patients received stage‐specific therapy according to the latest national guidelines, irrespective of the mode of detection.

Results

The benefit for women who chose to participate in an organized breast cancer screening program was a 60% lower risk of dying from breast cancer within 10 years after diagnosis (relative risk, 0.40; 95% confidence interval, 0.34‐0.48) and a 47% lower risk of dying from breast cancer within 20 years after diagnosis (relative risk, 0.53; 95% confidence interval, 0.44‐0.63) compared with the corresponding risks for nonparticipants.

Conclusions

Although all patients with breast cancer stand to benefit from advances in breast cancer therapy, the current results demonstrate that women who have participated in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than do those who have not participated.

After 20 years of follow‐up, women who participate in mammography screening have a 47% lower risk of dying from breast cancer. Although all patients with breast cancer potentially can benefit from advances in breast cancer therapy, women who participate in mammography screening obtain a significantly greater benefit from the therapy available at the time of diagnosis than those who do not participate.

The impact of mammography screening programmes on incidence of advanced breast cancer in Europe: a literature review

Background

Observational studies have reported conflicting results on the impact of mammography service screening programmes on the advanced breast cancer rate (ABCR), a correlation that was firmly established in randomized controlled trials. We reviewed and summarized studies of the effect of service screening programmes in the European Union on ABCR and discussed their limitations.

Methods

The PubMed database was searched for English language studies published between 01-01-2000 and 01–06-2018. After inspection of titles and abstracts, 220 of the 8644 potentially eligible papers were considered relevant. Their abstracts were reviewed by groups of two authors using predefined criteria. Fifty studies were selected for full paper review, and 22 of these were eligible. A theoretical framework for their review was developed. Review was performed using a ten-point checklist of the methodological caveats in the analysis of studies of ABCR and a standardised assessment form designed to extract quantitative and qualitative information.

Results

Most of the evaluable studies support a reduction in ABCR following the introduction of screening. However, all studies were challenged by issues of design and analysis which could at least potentially cause bias, and showed considerable variation in the estimated effect. Problems were observed in duration of follow-up time, availability of reliable reference ABCR, definition of advanced stage, temporal variation in the proportion of unknown-stage cancers, and statistical approach.

Conclusions

We conclude that much of the current controversy on the impact of service screening programmes on ABCR is due to observational data that were gathered and/or analysed with methodological approaches which could not capture stage effects in full. Future research on this important early indicator of screening effectiveness should focus on establishing consensus in the correct methodology.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4666-1) contains supplementary material, which is available to authorized users.

Impact of breast cancer screening in a population with high spontaneous coverage with mammography

OBJECTIVE

The impact of organized screening programs on breast cancer (BC) mortality is unclear in an era of high spontaneous referral of women to mammography. The aim of this study was to analyze if the introduction of mammographic screening programs reduced BC mortality in the Veneto region, Italy, despite already widespread spontaneous access to mammography.

METHODS

In Veneto, screening was introduced in different years between 1999 and 2009 across 21 local health units (LHUs), inviting asymptomatic women aged 50-69 years to undergo mammography biennially. We compared BC mortality for the 1995-2014 period of women aged 40-49 and 50-74 years who were resident in LHUs where screening programs started in 2003 (early LHUs) with women resident in LHUs where screening was introduced later (late LHUs). Poisson regression models were applied to incidence-based mortality (IBM), including only deaths from BC arising within the screening period.

RESULTS

In the prescreening period and until 2010, BC mortality rates in early and late LHUs were similar in both age groups. In the last study period (2010-2014), we observed a 10% decrease in overall BC mortality in early compared to late LHU, limited to women aged 50-74 years. IBM was reduced by 8% (95% CI 1%-16%) in the overall study period and by 16% (6%-25%) in 2010-2014.

CONCLUSIONS

In the Veneto region, screening programs were associated with a significant impact on BC-specific mortality; such effect appeared at least 8 years after screening implementation.

A cohort study of mammography screening finds that comorbidity measures are insufficient for controlling selection bias

OBJECTIVE

To examine the potential of claims-based comorbidity measures for controlling selection bias in observational studies of mammography screening.

STUDY DESIGN AND SETTING

Based on claims data of a large German Statutory Health Insurance fund, the single comorbidities considered by the Charlson, Elixhauser, Multipurpose Australian Comorbidity Scoring System, and M3 comorbidity measures were identified for mammography screening participants and nonparticipants. Total death rates within 4 years after screening invitation were compared. Cox proportional hazards regressions were performed unadjusted and adjusted for age, federal state of residence, and comorbidity.

RESULTS

Among 1,247,919 insured women aged 50-68 years (56.2% participants), 10,311 participants (death rate 375.8/100,000 person-years) and 18,113 nonparticipants (death rate 854.8/100,000 person-years) died from any cause during the follow-up. The unadjusted hazard ratio (HR) for death from any cause for participants vs. nonparticipants was 0.44 (99.9% confidence interval 0.42-0.46). Adjustments attenuated the HR to a maximum of 0.52 (0.50-0.54).

CONCLUSION

The lower short-term all-cause mortality among participants cannot be explained by mammography screening effects and should be interpreted as selection bias. Adjusting for comorbidities only slightly attenuated this bias. Future studies should examine whether claims data include further information that is beneficial to adequately control selection bias in observational studies of mammography screening.

Aggressive primary treatments with favourable 5-year survival for screen-interval breast cancers

Background

To assess the impact of the participation in screening programme according to the mode of detection on the early diagnosis, treatment, and specific survival outcomes in women with breast cancer.

Methods

Women diagnosed with invasive breast cancer in Poitou-Charentes region (France) between 2008 and 2009 were classified into three groups, using data linkage of cancer registry, vital statistics and French organized screening programme: the screening programme (SP), interval cancer (IC), and non-screening programme detected cancer (NSP) groups. Specific survival rates were analysed using the Kaplan–Meier method and Cox proportional hazard models.

Results

Among 1613 patients, 65.7% (n = 1059) participated in a screening programme. The interval cancer rate was 17.1% (n = 181). Tumours in the IC group were diagnosed at a more advanced stage, i.e. with further regional lymph node metastasis or local spread, than those in the SP group (p < 0.001), but with significantly fewer metastases at diagnosis than in the NSP group (p < 0.001). ICs underwent more aggressive primary treatments than the two other groups, with 28% of radical mastectomy and 67% undergoing chemotherapy. The five-year survival rate for IC group were 92.0% (95% CI, 89.9–94.0%).

Conclusions

Interval cancers had more aggressive features than screen-detected cancers but were diagnosed at a less advanced stage compared to non-screen detected cancers. Despite having cancers missed by the screening programme, women who participate in the screening process seem to benefit from early treatment. These results must be confirmed with long-term follow-up.

The effect of population-based mammography screening in Dutch municipalities on breast cancer mortality: 20 years of follow-up

Long-term follow-up data on the effects of screening are scarce, and debate exists on the relative contribution of screening versus treatment to breast cancer mortality reduction. Our aim was therefore to assess the long-term effect of screening by age and time of implementation. We obtained data on 69,630 breast cancer deaths between 1980 and 2010 by municipality (N = 431) and age of death (40-79) in the Netherlands. Breast cancer mortality trends were analyzed by defining the municipality-specific calendar year of introduction of screening as Year 0. Additionally, log-linear Poisson regression was used to estimate the turning point in the trend after Year 0, per municipality, and the annual percentage change (APC) before and after this point. Twenty years after introduction of screening breast cancer mortality was reduced by 30% in women aged 55-74 and by 34% in women aged 75-79, compared to Year 0. A similar and significant decrease was present in municipalities that started early (1987-1992) and late (1995-1997) with screening, despite the difference in availability of effective adjuvant treatment. In the age groups 55-74 and 75-79, the turning point in the trend in breast cancer mortality was estimated in Years 2 and 6 after the introduction of screening, respectively, after which mortality decreased significantly by 1.9% and 2.6% annually. These findings show that the implementation of mammography screening in Dutch municipalities is associated with a significant decline in breast cancer mortality in women aged 55-79, irrespective of time of implementation.

Early detection of breast cancer in Brazil: data from the National Health Survey, 2013

OBJECTIVE

To analyze whether the actions of early detection of breast cancer, initiated with the medical request for mammography, differ between users of the Brazilian Unified Health System (SUS) and those who have private health insurance.

METHODS

From the data collected in the National Health Survey, we estimated the proportions of women who had medical request for mammography according to presence or absence of private health insurance. For assessing the factors related to having mammography medical request, we estimated crude and adjusted odds ratios and respective 95%CI by logistic regression. We also analyzed the main reasons reported for not having performed mammography after medical request, as well as the time between examination and result.

RESULTS

Of the women interviewed, 66.7% had a medical request for mammography (59.4% among SUS users and 83.9% among those with private health insurance). Having private health insurance, higher education level, and being white were positively associated with having the medical request. Only 5.4% (95%CI 4.8-6.0) of women who received medical request failed to perform mammography - 7.6% were SUS users and 1.7% had health insurance. The most reported reasons for not being able to perform the examination were: not thinking it was necessary; having the test scheduled, but not yet performed; and not being able to schedule it. More than 70% of women received the result with less than one month from its execution.

CONCLUSIONS

The barriers to access a medical request for mammographic screening for breast cancer are higher among women who depend exclusively on SUS.

Advanced breast cancer rates in the epoch of service screening: The 400,000 women cohort study from Italy

BACKGROUND

The objective of this study was to evaluate if mammography screening attendance is associated with a reduction in late-stage breast cancer incidence.

METHODS

The cohort included over 400,000 Italian women who were first invited to participate in regional screening programmes during the 1990s and were followed for breast cancer incidence for 13 years. We obtained individual data on their exposure to screening and correlated this with total and stage-specific breast cancer incidence. Socio-economic status and pre-screening incidence data were used to assess the presence of self-selection bias.

RESULTS

Overall, screening attendance was associated with a 10% excess risk of in situ and invasive breast cancer (IRR = 1.10; 95% confidence interval (CI): 1.06-1.14), which dropped to 5% for invasive cancers only (IRR = 1.05; 95% CI: 1.01-1.09). There were significant reductions among attenders for specific cancer stages; we observed a 39% reduction for T2 or larger (IRR = 0.61; 95% CI: 0.57-0.66), 19% for node positives (IRR = 0.81; 95% CI: 0.76-0.86) and 28% for stage II and higher (IRR = 0.72; 95% CI: 0.68-0.76). Our data suggest that the presence of self-selection bias is limited and, overall, invited women experienced a 17% reduction of advanced cancers compared with pre-screening rates.

CONCLUSIONS

Comparing attenders' and non-attenders' stage-specific breast cancer incidence, we have estimated that screening attendance is associated with a reduction of nearly 30% for stages II+.

Effect of population breast screening on breast cancer mortality up to 2005 in England and Wales: an individual-level cohort study

BACKGROUND

Population breast screening has been implemented in the UK for over 25 years, but the size of benefit attributable to such programmes remains controversial. We have conducted the first individual-based cohort evaluation of population breast screening in the UK, to estimate the impact of the NHS breast screening programme (NHSBSP) on breast cancer mortality.

METHODS

We followed 988 090 women aged 49-64 years in 1991 resident in England and Wales, who because of the staggered implementation of the NHSBSP, included both invited subjects and an uninvited control group. Individual-level breast screening histories were linked to individual-level mortality and breast cancer incidence data from national registers. Risk of death from breast cancer was investigated by incidence-based mortality analyses in relation to intention to screen and first round attendance. Overdiagnosis of breast cancer following a single screening round was also investigated.

RESULTS

Invitation to NHSBSP screening was associated with a reduction in breast cancer mortality in 1991-2005 of 21% (RR=0.79, 95% CI: 0.73-0.84, P<0·001) after adjustment for age, socioeconomic status and lead-time. Breast cancer deaths among first invitation attenders were 46% lower than among non-attenders (RR=0.54, 95% CI: 0.51-0·57, P<0.001) and 32% lower following adjustment for age, socioeconomic status and self-selection bias (RR=0.68, 95% CI: 0.63-0·73, P<0.001). There was little evidence of overdiagnosis associated with invitation to first screen.

CONCLUSIONS

The results indicate a substantial, statistically significant reduction in breast cancer mortality between 1991 and 2005 associated with NHSBSP activity. This is important in public health terms.

Balancing the benefits and detriments among women targeted by the Norwegian Breast Cancer Screening Program

Objective

To compute a ratio between the estimated numbers of lives saved from breast cancer death and the number of women diagnosed with a breast cancer that never would have been diagnosed during the woman’s lifetime had she not attended screening (epidemiologic over-diagnosis) in the Norwegian Breast Cancer Screening Program.

Methods

The Norwegian Breast Cancer Screening Program invites women aged 50–69 to biennial mammographic screening. Results from published studies using individual level data from the programme for estimating breast cancer mortality and epidemiologic over-diagnosis comprised the basis for the ratio. The mortality reduction varied from 36.8% to 43% among screened women, while estimates on epidemiologic over-diagnosis ranged from 7% to 19.6%. We computed the average estimates for both values. The benefit–detriment ratio, number of lives saved, and number of women over-diagnosed were computed for different scenarios of reduction in breast cancer mortality and epidemiologic over-diagnosis.

Results

For every 10,000 biennially screened women, followed until age 79, we estimated that 53–61 (average 57) women were saved from breast cancer death, and 45–126 (average 82) were over-diagnosed. The benefit–detriment ratio using average estimates was 1:1.4, indicating that the programme saved about one life per 1–2 women with epidemiologic over-diagnosis.

Conclusion

The benefit–detriment ratio estimates of the Norwegian Breast Cancer Screening Program, expressed as lives saved from breast cancer death and epidemiologic over-diagnosis, should be interpreted with care due to substantial uncertainties in the estimates, and the differences in the scale of values of the events compared.

Women with abnormal screening mammography lost to follow-up: An experience from Taiwan

Breast cancer has the highest incidence among all cancers for women in Taiwan. The current screening policy in Taiwan suggested a biennial mammography for all women 40 to 69 years of age. A recommendation for additional testing is recommended for women with a BI-RADS result of 0 or 4; a request made via postal mail. Approximately 20% of high-risk patients do not receive additional follow-up. Therefore, we aimed to explore the causes of these patients being lost to follow-up, despite an abnormal mammogram. Two questionnaires were designed separately according to the conceptual framework of the Health Belief Model. Study participants, women who received a screening mammography at the National Taiwan University Hospital in 2011 with a BI-RAD of 0 or 4, were interviewed via telephone. The dependent variable was receipt of follow-up or not. The analyses were performed by using χ tests and logistic regression models. In total, 528 women were enrolled in the study: 51.2% in BI-RADS 0 group and 56.6% in BI-RADS 4, respectively. In the BI-RADS 0 group, those patients who received a follow-up examination cited the most likely causes to be physician suggestion, health implications, and concerns regarding breast cancer. Patients who did not receive a follow-up examination cited a lack of time and a perception of good personal health as primary reasons. In the BI-RADS 4 group, those patients who received a follow-up examination cited the physician's recommendation and a recognition of the importance of follow-up examinations. Patients who did not receive a follow-up examination cited having received follow-up at another hospital and a desire for a second opinion. In the BI-RADS 0 group, multivariate analysis showed that patients with higher scores in the "perceived benefits" domain were statistically more likely to receive a follow-up examination. There was no significant difference in perceived threats, perceived barriers, action cues, or self-efficacy between groups. We conclude that additional education to raise breast cancer awareness in the general public and healthcare providers will be needed to improve the rate of follow-up examinations after an abnormal screening mammogram.

Recent changes in breast cancer incidence and mortality in Estonia: Transition to the west

Background The aim of this study was to examine breast cancer (BC) incidence and mortality trends in Estonia during recent decades and to compare the pattern of these trends with other selected European countries and regions. We attempt to explain the findings in relation to changes in Estonian society and healthcare system. Methods BC incidence (1985-2012) and mortality (1985-2013) data for Estonia were obtained from the Estonian Cancer Registry and Statistics Estonia. Data for selected European countries were obtained from the EUREG database. Joinpoint regression was used to analyze age-standardized rates in Estonia by age. For international comparison of incidence and mortality rates, we used scatterplot with 95% confidence ellipses and the mortality to incidence ratio. Results The overall BC incidence continues to increase in Estonia, while mortality has been in decline since 2000. Both incidence and mortality trends varied considerably across age groups. Among women aged 60 years and older, BC incidence increased at a rate of nearly 3% per year. Significant decrease in mortality was seen only among women aged 50-59 years. Comparison of scatterplots between countries and regions revealed two clusters in Europe separated along the incidence axis. The correlation between incidence and mortality in Estonia changed its direction in the mid-1990s. Conclusion In recent years, the dynamics of BC burden in Estonia has transitioned towards the high incidence-low mortality type model, which is characteristic to Western, Northern and Southern Europe. Although overall BC incidence is much lower in Estonia than in more affluent European countries, mortality from BC is still relatively high, particularly among elderly women.

The Balance Sheet of Benefits and Harms of Breast Cancer Population-Based Screening in Europe: Outcome Research, Practice and Future Challenges

Breast cancer screening programs are still object of harsh debate. In 2012, the Independent UK Panel reviewed the benefits and harms of mammography screening based on randomized trials and the EUROSCREEN Working Group reviewed European observational outcome studies. The conclusion was that screening programs should continue, while acknowledging that harms, such as the occurrence of false-positive results and overdiagnosis, can have a negative impact on a woman's life. Information on the balance sheet of the benefits and harms of breast cancer screening should help women and their physicians to make an informed choice. The future challenge for breast screening programs is to assess the feasibility, acceptability, effectiveness and impact of risk-based screening in order to maximize benefit-to-harm ratios.

Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update From the American Cancer Society

IMPORTANCE

Breast cancer is a leading cause of premature mortality among US women. Early detection has been shown to be associated with reduced breast cancer morbidity and mortality.

OBJECTIVE

To update the American Cancer Society (ACS) 2003 breast cancer screening guideline for women at average risk for breast cancer.

PROCESS

The ACS commissioned a systematic evidence review of the breast cancer screening literature to inform the update and a supplemental analysis of mammography registry data to address questions related to the screening interval. Formulation of recommendations was based on the quality of the evidence and judgment (incorporating values and preferences) about the balance of benefits and harms.

EVIDENCE SYNTHESIS

Screening mammography in women aged 40 to 69 years is associated with a reduction in breast cancer deaths across a range of study designs, and inferential evidence supports breast cancer screening for women 70 years and older who are in good health. Estimates of the cumulative lifetime risk of false-positive examination results are greater if screening begins at younger ages because of the greater number of mammograms, as well as the higher recall rate in younger women. The quality of the evidence for overdiagnosis is not sufficient to estimate a lifetime risk with confidence. Analysis examining the screening interval demonstrates more favorable tumor characteristics when premenopausal women are screened annually vs biennially. Evidence does not support routine clinical breast examination as a screening method for women at average risk.

RECOMMENDATIONS

The ACS recommends that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years (strong recommendation). Women aged 45 to 54 years should be screened annually (qualified recommendation). Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually (qualified recommendation). Women should have the opportunity to begin annual screening between the ages of 40 and 44 years (qualified recommendation). Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer (qualified recommendation). The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age (qualified recommendation).

CONCLUSIONS AND RELEVANCE

These updated ACS guidelines provide evidence-based recommendations for breast cancer screening for women at average risk of breast cancer. These recommendations should be considered by physicians and women in discussions about breast cancer screening.

The value of modern mammography screening in the control of breast cancer: understanding the underpinnings of the current debates

Since the introduction of mammography screening, debates about the value of screening have endured and been contentious. Recent reviews of the randomized controlled trials reach different conclusions about the absolute benefit of screening, as do evaluations of population trends in breast cancer mortality and the evaluations of service screening. Conclusions about the value of screening commonly are expressed in terms of the balance of benefits and harms, which can differ greatly even when derived seemingly from the same data. It can be shown when different estimates are adjusted to a common screening and follow-up scenario, differences in balance sheet estimates diminish substantially. The strong evidence of benefit associated with exposure to modern mammography screening suggests that it is time to move beyond the randomized controlled trial estimates of benefit and consider policy decisions on the basis of benefits and harms estimated from the evaluation of current screening programs.

European breast cancer service screening outcomes: a first balance sheet of the benefits and harms

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.

Interval cancer rates in the Irish national breast screening programme

OBJECTIVE

To compare interval cancer rates from the Irish breast screening programme, BreastCheck, for the period 2000-2007 with those from other European countries.

METHODS

Data from BreastCheck was linked to National Cancer Registry breast cancer registrations, to calculate numbers of women screened, screen-detected cancers, and interval cancers, by year of screening, in the first and second years after screening, and by initial or subsequent screen. Estimated underlying cancer incidence from the period 1996-1999 inclusive was used to calculate proportionate incidence. We calculated the interval cancer ratio as an alternative measure of the burden of interval cancers.

RESULTS

There were 372,658 screening records for 178,147 women in the period 2000-2007. The overall interval rate was 9.6 per 10,000 screens. In the first year after screening, the interval cancer rate was 5.8 per 10,000 screens and this increased to 13.4 in the second year after screening. The screen detection rate for the period was 53.6 per 10,000 screened for all screens combined. Initial screens produced a higher detection rate at 66.9 per 10,000 screened compared with subsequent screens with a screen-detected rate of 41.4 per 10,000 screens.

CONCLUSION

Interval breast cancer rates for the first years of the programme are within acceptable limits and are comparable with those in other European programmes. Nationwide roll-out together with the adoption of digital mammography may have an impact on interval cancer rates in future years.

[Access to early breast cancer diagnosis in the Brazilian Unified National Health System: an analysis of data from the Health Information System]

The recent reduction in breast cancer mortality in high-income countries resulted from improvements in early detection and treatment. Breast cancer is the most common cancer in Brazilian women. Since 2004, the government has recommended annual clinical breast examination for women aged ≥ 40 years and biannual mammograms for those aged 50-69. This article investigates the degree of implementation of these guidelines using data from the Brazilian Unified National Health System for 2010 according to major geographic region and age group. The findings showed low national mammogram coverage in the target population (32% in the 50-59-year group; 25% from 60 to 69 years). The percentage of women with abnormal radiological findings who underwent biopsy was also low (27% for 50-59 years; 63% for 60-69 years). The number of breast cancer surgeries exceeded the number of cases detected by mammography but was well below the estimated number of incident breast cancer cases in 2010. There are striking regional inequalities in access to early detection and surgery, being the lowest access in the North Region and the highest in the South Region.

Mammography screening in three Finnish residential areas: comprehensive population-based study of breast cancer incidence and incidence-based mortality 1976-2009

BACKGROUND

The aim of this study was to evaluate the effectiveness of a large-scale screening programme for breast cancer (BC) in Turku, Finland. Incidence and incidence-based mortality (IBM) figures were compared with the areas applying different screening policies.

METHODS

Deaths and person-time of women aged 40-84 were assessed for the period 1976-1986 (prescreening era) and the periods 1987-1997 and 1998-2009 (screening periods) using incidence and IBM by age at diagnosis and at death. There was a total of 40.7 million women-years, 83 497 invasive BCs obtained from the Finnish Cancer Registry; 17 508 BC deaths were linked with the data from Statistics Finland.

RESULTS

In Turku, a significant (> 20%) reduction in IBM occurred during 1987-2009 among women aged 60-74 years at diagnosis compared with Helsinki (IBMRR: 0.75, 95% CI: 0.57-1.00), and in women aged 75-84 years at death compared with the rest of Finland (IBMRR: 0.72, 95% CI: 0.53-0.96).

CONCLUSIONS

The wide mammography screening programme in Turku was effective in decreasing BC mortality in the elderly age groups. These results support the implementation of BC screening from age 50 up to 74 years.