Breast Cancer Screening Program Research Articles

Beyond a decade: a comparative study of 15-year survival rates in screen-detected vs. symptomatic breast cancer patients in Hungary

BackgroundBreast cancer is the leading cancer in women globally. Despite decreasing mortality rates, largely due to early detection and modern treatment, the effectiveness of screening on long-term survival outcomes remains unclear.AimsThis study evaluates the 15-year survival outcomes of a national breast cancer screening program initiated in Hungary in 2002.MethodsUsing a prospectively maintained patient database, the study included individuals from the first 6 years of the program who underwent surgery for histologically confirmed breast cancer and had available follow-up information. Patients were categorized based on the method of breast cancer detection into two groups: those diagnosed during or 2 years after the population-based screening exam (Group A), and those who self-detected or sought medical attention for symptoms (Group B).ResultsOf the 309 patients who underwent breast cancer surgery, 208 were screen-detected (Group A) and 101 were symptomatic (Group B). The 15-year overall survival was 75.0% for Group A and 76.2% for Group B (p = 0.927). The 15-year disease-specific survival was 85.6% and 81.2% (p = 0.249), respectively. A statistically not significant positive trend in disease-free survival was observed in Group A (81.7% vs. 75.2%; p = 0.144).ConclusionsThe study underscores the importance of extended follow-up periods in evaluating the outcomes of breast cancer screening programs. While the screening program may not significantly enhance overall survival rates, it has demonstrated a reduction in the mastectomy rate and could potentially extend periods of disease-free survival. These findings contribute to the ongoing discourse about the long-term benefits of breast cancer screening programs.

The Influence of Age Limitation of the German Breast Cancer-Screening Program on Female Patients Older Than 69 Years: A Single-Institutional Retrospective Study

Background: The breast cancer-screening program is defined as including women between 50 and 69 years old and aims to detect breast cancer in its early stages, which improves the survival outcome. The aim of this study is to explore the differences between female cancer patients at ages between 50 and 69 years old and those older than 69 years regarding the initial tumor stage, method of tumor detection, and conducted oncological treatment. Methods: Between January 2017 and August 2020, we recruited all breast cancer female patients older than 69 years old who were diagnosed with breast cancer and planned to receive radiotherapy. A similar sample size of female patients between 50 and 69 years old, who were presented to receive radiotherapy at the defined time of the study, was used as a reference group to be compared with the study group. Results: We identified 132 female patients older than 69 years with breast cancer, who were presented in our department to receive radiotherapy. The control group was represented by 131 female patients at the ages between 50 and 69 years old. The most common stage detected at the time of diagnosis in both groups was stage IA which represented 29% of the study group and 41% of the controlled group. The incidence of Stage IV is significantly higher in the study group (9%) in comparison to the control group (0.8%). Conclusion: Stage IA is the most common tumor stage detected among female patients older than 69 years as well as those involved in the breast cancer-screening program. The incidence of metastatic disease is significantly higher among patients not involved in the screening program.

Application of SHAP for Explainable Machine Learning on Age-Based Subgrouping Mammography Questionnaire Data for Positive Mammography Prediction and Risk Factor Identification.

Mammography is considered the gold standard for breast cancer screening. Multiple risk factors that affect breast cancer development have been identified; however, there is an ongoing debate regarding the significance of these factors. Machine learning (ML) models and Shapley Additive Explanation (SHAP) methodology can rank risk factors and provide explanatory model results. This study used ML algorithms with SHAP to analyze the risk factors between two different age groups and evaluate the impact of each factor in predicting positive mammography. The ML model was built using data from the risk factor questionnaires of women participating in a breast cancer screening program from 2017 to 2021. Three ML models, least absolute shrinkage and selection operator (lasso) logistic regression, extreme gradient boosting (XGBoost), and random forest (RF), were applied. RF generated the best performance. The SHAP values were then applied to the RF model for further analysis. The model identified age at menarche, education level, parity, breast self-examination, and BMI as the top five significant risk factors affecting mammography outcomes. The differences between age groups ranked by reproductive lifespan and BMI were higher in the younger and older age groups, respectively. The use of SHAP frameworks allows us to understand the relationships between risk factors and generate individualized risk factor rankings. This study provides avenues for further research and individualized medicine.

Evaluation of the implementation of screening programs for early detection of breast and cervical cancer in the Gomel region

Objective. Conduct a comprehensive assessment of the indicators of screening programs for early detection of breast and cervical cancer in the Gomel region.Materials and methods. A total of 7,611 first-time detected cases of breast cancer and 1,370 cases of cervical cancer in the Gomel region were analyzed for the period 2012-2022 (according to Belarusian Cancer Registry). The results of examination of 105130 participants of the screening program for early detection of breast cancer and 70258 participants of the screening program for early detection of cervical cancer were analyzed.Results. During the period 2017-2022, due to screening, 12% of cases of breast cancer were detected from the total number of newly diagnosed malignant breast pathologies. From 2018 to 2022, the proportion of newly detected cases of cervical cancer within the screening program increased from 0.83% to 2.61%, which indicates that the introduction of the screening program contributes to an increase in the detection of precancerous conditions of the cervix.Conclusions. The screening program for breast cancer and cervical cancer has shown its effectiveness in detecting new cases of malignant neoplasms of these localizations. An important result of the screening conducted in the Gomel region is the fact that the observed trend towards a decrease in the detection of breast cancer and cervical cancer in the early stages does not give any cause for optimism, as this is evidence of a deterioration in the structure of the detected pathology.

Factors Influencing Iranian Women's Participation in Breast Cancer Screening Programs: A Systematic Review

Background: Breast cancer screening programs are one of the most important methods for the early detection of breast cancer in women. Several studies have been conducted to identify factors affecting breast cancer screening behaviors among Iranian women. This study is conducted to systematically review the factors influencing women’s participation in breast cancer screening programs in Iran.
 Methods: Papers were collected by using the keywords breast, mammary, screening, early detection, diagnosis*, examination, testing, and Iran from various English-language databases, including PubMed, Scopus, Web of Science, and databases in Persian language including SID and Magiran. The search was limited to the title and abstract of papers published between January 1, 2000, and May 1, 2021. A narrative synthesis was performed to summarize findings of the obtained papers.
 Results: In this study, 1345 papers were initially found and, after screening the title, abstract, and full-text, 39 papers were selected. Most of them were cross-sectional (n= 28). Results indicated that socioeconomic factors, individual characteristics, recommendation of health workers, knowledge, Islamic beliefs, support by family, and activities of the Iranian government are frequently mentioned as contributing factors and can be applied to increase participation of Iranian women in breast cancer screening.
 Conclusion: The results demonstrate that lack of knowledge and a positive attitude towards breast cancer screening is a major problem regarding Iranian women's non-participation in the screening programs. Therefore, the need for regular implementation of the national screening program in the country, providing appropriate educational methods to increase women's awareness, removing barriers and improving women's access to health care providers should be the priorities of the Iranian health system to prevent breast cancer.

Awareness on breast cancer among females at Bharatpur metropolitan, Chitwan, Nepal

Introduction: Breast cancer is the most frequently diagnosed cancer in the world and second most common malignancy among Nepalese women with high prevalence. Countries with lower level of resources like Nepal, prevention of breast cancer is more important. The objective of the study was to find out the level of awareness on breast cancer among female at Bharatpur Metropolitan, Nepal. Methods: An analytical cross- sectional study was conducted among 263 female of Bharatpur Metropolitan city, Nepal. Non probability purposive sampling technique was used for data collection. Data was entered and analyzed by using SPSS-20, p-value <0.05 was considered as statistically significant. Results: The mean±SD of age was found 34.40±11.42 years. Study showed that 61.2% (with 95% CI as 55.32-67.1%) had good awareness on risk factors, 60.5% (with 95% CI as 54.54-66.36) had good awareness on warning sign and symptoms and only 44.5% (with 95% CI as 38.48-50.49) had good awareness on screening and prevention. Overall level of awareness on breast cancer was found poor (50.2%). The mean+SD of overall awareness of the respondents on breast cancer was 15.51±2.84. Statistical significant association was found between overall level of awareness and respondents’ education (p=0.039), husband education (p=0.011) and occupation (p=0.046) of the respondents. Conclusions: More than half of the respondents has poor level of awareness on breast cancer among women in Bharatpur, Chitwan, Nepal. Better health awareness among women in the community, breast cancer screening programmes and national policies to establish effective cancer literacy programs would cause a favorable and positive clinical picture in the country.

Determinants of cancer screenings participation in Queensland: a scoping review.

Introduction Cancer screening programmes for cervical, breast, and colorectal cancer have successfully reduced mortality rates among target groups. However, a large proportion of women and men are unscreened. Aim This review aims to provide an overview of the literature regarding the determinants of cancer screening participation among target groups in Queensland. Methods Electronic databases were searched for studies on determinants of cancer screening participation in Queensland. Retrieved studies were screened, and eligible articles were selected for data extraction. Both peer-reviewed and grey literature studies were included. The determinants of cancer screening participation were classified according to the I-Change model. Results Sixteen out of 75 articles were selected and analysed. Information factors, such as the lack of tailored strategies, determined cancer screening participation. Age, gender, cultural beliefs, fear and past experiences were the most reported predisposing factors to cancer screening participation. Lack of knowledge, misconceptions, low awareness, timely access to service, privacy and confidentiality were mainly reported awareness and motivation factors. Encouragement from health professionals, providing more information and interactions with communities would result in different effects on cancer screening participation among the target groups. Discussion The I-Change model is a valuable tool in mapping the current determinants of cancer screening participation programs. Further research may be needed to fully understand the barriers and facilitators of cancer screening programs.

Breast Cancer in Brazil: Screening Program and Surgical Approach

Breast cancer is the most common female cancer, and Screening mammography is a current strategy that reduces mortality among women. In Brazil, more recent data show an increasing number of mammograms but unequal geographic access to the exam nationwide. Breast surgery is essential to the current oncological treatment and management of breast cancer. Conservative breast techniques have been established as an effective treatment option; however, mastectomies are still widely used in Brazil. The increase in breast cancer screening programs nationwide should increase the number of breast-conserving surgeries over total mastectomies. However, these expectations may be compromised in developing countries such as Brazil, where there are relevant discrepancies in the public health system.

Utilisation and Predictors of Breast Self-Examination among Female Nurses in a Tertiary Medical Centre in North Central Nigeria

The incidence of breast cancer is increasing in many underdeveloped nations and constituted a major public health burden. Despite this, most breast cancer patients in many underdeveloped nations present with late diseases when few options of treatment are available. Early detection through screening remains the main means of improving breast cancer outcomes. Nurses are a group of healthcare professionals and are thus expected to advocate for breast cancer screening programs. This study was conducted to determine the extent of utilisation and predictors of the practice of breast self-examination among nurses in a tertiary health care centre. The study prospectively surveyed 189 nurses on knowledge and practice of breast self-examination (BSE) using a stratified random sampling technique. Data were obtained through a pretested self-administered structured questionnaire. The mean age of the respondents was 41.44 (±5.66) years. Sixty-seven (35.4%) of the respondents practiced BSE of which only 31.3% practiced it monthly as recommended. Family history of breast cancer (p<0.001), age greater than 50 (p<0.001), post-menopausal women (p<0.001), and posting in surgical-related wards (p<0.001) were significantly associated with the practice of BSE. The practice of BSE among the respondents was poor and the few who practiced it lacked the correct technique. The teaching of BSE should be encouraged at nursing schools with an emphasis on practice and techniques. We also suggest a need for continued nursing education. Keywords: Breast self-examination, utilisation, predictors, nurses, breast cancer, screening.

Functional forms of socio-territorial inequities in breast cancer screening – A French cross-sectional study using hierarchical generalised additive models

To reduce the breast cancer burden, the French National Organised Breast Cancer Screening Programme (FNOBCSP) was implemented in 2004. The recommended participation rate has never been achieved and socio-territorial inequities in participation have been reported on several occasions. We investigated the functional forms and consistency of the relationships between neighbourhood deprivation, travel time to the nearest accredited radiology centre and screening uptake. We used two-level hierarchical generalised additive models in 8 types of territories classified by socio-demographic and economic factors. The first level was 368,201 women aged 50–72 invited to the 2013–2014 screening campaign in metropolitan France. They were nested in 41 départements, the level of organisation of the FNOBCSP. The effect of travel time showed two main patterns: it was either linear (with participation decreasing as travel time increased) or participation first increased with increasing travel time to a peak around 5–15 min and decreased afterward. In nearly all types and départements, the probability of participation decreased linearly with increasing deprivation. Territorial inequities in participation were more context-dependent and complex than social inequities. Inequities in participation represent a loss of opportunity for individuals who already have the worst cancer outcomes. Evidence-based public health policies are needed to increase the effectiveness and equity of breast cancer screening.

IMPACT OF COVID-19 ON BREAST CANCER SCREENING PROGRAM (BCSP) IN INDIA

In the past three years, covid-19 viruses have spread rapidly worldwide, while low and middle-income countries were affected mostly so far. Emergency limits were imposed due to the rapid infection and significant mortality rates. Only emergency medical treatments are available during these shutdowns and lockdowns in India. All non-emergency treatments, such as Breast Cancer Screening Program (BCSP), have been temporarily halted due to the huge number of deaths caused by coronavirus. However, the ability of BC screening programs to improve survival rates while lowering mortality rates has been well demonstrated. Suspension may result in poorer outcomes for patients with BC. In this regard, early detection and treatment are critical for increased survival and long-term quality of life. Thus, we have taken breast cancer patients' data for the last six years i.e. from 2016 to 2021 in India to properly evaluate and analyze for our research. Assessing recent results for various features from, modeled evaluations can aid pandemic responses. Besides that, we proposed a novel method that implements the EDA technique to graphically represent BC patients' data. This experiment was done using Python programming language on Jupyter 6.4.3 platform. We found the sudden rise of BC patients from lakhs to millions in 2019. This signifies the deadly coronavirus has greatly affected people during the pandemic days when people are more serious about this virus rather than screening their breasts.

IMPACT OF COVID-19 ON BREAST CANCER SCREENING PROGRAM (BCSP) IN INDIA

In the past three years, covid-19 viruses have spread rapidly worldwide, while low and middle-income countries were affected mostly so far. Emergency limits were imposed due to the rapid infection and significant mortality rates. Only emergency medical treatments are available during these shutdowns and lockdowns in India. All non-emergency treatments, such as Breast Cancer Screening Program (BCSP), have been temporarily halted due to the huge number of deaths caused by coronavirus. However, the ability of BC screening programs to improve survival rates while lowering mortality rates has been well demonstrated. Suspension may result in poorer outcomes for patients with BC. In this regard, early detection and treatment are critical for increased survival and long-term quality of life. Thus, we have taken breast cancer patients' data for the last six years i.e. from 2016 to 2021 in India to properly evaluate and analyze for our research. Assessing recent results for various features from, modeled evaluations can aid pandemic responses. Besides that, we proposed a novel method that implements the EDA technique to graphically represent BC patients' data. This experiment was done using Python programming language on Jupyter 6.4.3 platform. We found the sudden rise of BC patients from lakhs to millions in 2019. This signifies the deadly coronavirus has greatly affected people during the pandemic days when people are more serious about this virus rather than screening their breasts.

Artificial Intelligence Applications in Breast Imaging: Current Status and Future Directions.

Attempts to use computers to aid in the detection of breast malignancies date back more than 20 years. Despite significant interest and investment, this has historically led to minimal or no significant improvement in performance and outcomes with traditional computer-aided detection. However, recent advances in artificial intelligence and machine learning are now starting to deliver on the promise of improved performance. There are at present more than 20 FDA-approved AI applications for breast imaging, but adoption and utilization are widely variable and low overall. Breast imaging is unique and has aspects that create both opportunities and challenges for AI development and implementation. Breast cancer screening programs worldwide rely on screening mammography to reduce the morbidity and mortality of breast cancer, and many of the most exciting research projects and available AI applications focus on cancer detection for mammography. There are, however, multiple additional potential applications for AI in breast imaging, including decision support, risk assessment, breast density quantitation, workflow and triage, quality evaluation, response to neoadjuvant chemotherapy assessment, and image enhancement. In this review the current status, availability, and future directions of investigation of these applications are discussed, as well as the opportunities and barriers to more widespread utilization.

Approximate Bayesian computation for the natural history of breast cancer, with application to data from a Milan cohort study.

We explore models for the natural history of breast cancer, where the main events of interest are the start of asymptomatic detectability of the disease (through screening) and the time of symptomatic detection (through symptoms). We develop several parametric specifications based on a cure rate structure, and present the results of the analysis of data collected as part of a motivating study from Milan. Participants in the study were part of a regional breast cancer screening program, and their ten-year trajectories were obtained from administrative data available from the Italian national health care system. We first present a tractable model for which we develop the likelihood contributions of the observed trajectories and perform maximum likelihood inference on the latent process. Likelihood based inference is not feasible for more flexible models, and we implement approximate Bayesian computation (ABC) for inference. Issues that arise from the use of ABC for model choice and parameter estimation are discussed, including the problem of choosing appropriate summary statistics. The estimated parameters of the underlying disease process allow for the study of the effect of different examination schedules (age range and frequency of screening examinations) on a population of asymptomatic subjects.

Attendance characteristics of the breast and colorectal cancer screening programmes in a highly urbanised region of the Netherlands: a retrospective observational study

ObjectivesThroughout Europe, many countries offer population-based cancer screening programmes (CSPs). In the Netherlands, two implemented CSPs are targeting people of 50 years and older, aiming at breast cancer (BC) and...

The impact of Covid-19 pandemic on breast cancer multidisciplinary management at the Vall d'Hebron University Hospital.

e18782 Background: The impact of breast cancer screening program interruption, restrictions and delays on diagnostic exams and access to primary care due to COVID-19 is not fully understood. We report our experience on breast cancer (BC) multidisciplinary management during 2020 in a Spanish COVID-19 reference centre, and the largest hospital in Catalonia. Methods: Cohort analysis of 2020 newly BC diagnosis, as compared to 2019 and 2018 period. Results: Overall, 54% less women were called to participate on the breast screening program and only 54% of those have accepted to take part of the program during March to May 2020 (lockdown period), as compared to 76% of acceptance in 2018/2019. Consequently, during the lockdown period there was a 38% reduction on breast oncologic surgeries and a 49% decrease on first medical oncology visits vs the same period of 2018/2019. Nevertheless, time from diagnosis to first oncologic treatment was similar between study periods. Stage IV BC diagnosis has doubled in 2020 representing 9.8% vs 4.2% and 4.8% in 2018 and 2019 respectively (p < 0.001). Medical oncologists’ decision on dose dense (dd) or weekly paclitaxel chemotherapy exposure have not changed in 2020 vs 2019. Conclusions: COVID-19 pandemic has had a strong impact on screening programs, with the double of patients being diagnosed at advanced stage in 2020, as compared to the two previous years.

The effect of attendance in the Dutch breast cancer screening program on breast tumor characteristics among migrant women.

In general, migrant women have a lower breast cancer (BC) incidence rate and higher BC mortality than autochthonous women. Further, migrant women show lower participation in the national BC screening program. To further investigate those aspects, we aimed to determine differences in incidence and tumor characteristics between autochthonous and migrant BC patients in Rotterdam, the Netherlands. We selected women diagnosed with BC in Rotterdam during 2012-2015 from the Netherlands Cancer Registry. Incidence rates were calculated by migrant status (i.e., women with or without migration background). Multivariable analyses revealed adjusted odds ratios (OR) and 95% confidence intervals (CI) on the association between migration status and patient and tumor characteristics, additionally stratified by screening attendance (yes/no). In total 1372 autochthonous and 450 migrant BC patients were included for analysis. BC incidence was lower among migrants than among autochthonous women. Overall, migrant women were younger at BC diagnosis (53 vs. 64 years, p<0.001), and had higher risks of positive lymph nodes (OR 1.76, 95% CI 1.33-2.33) and high grade tumors (OR 1.35, 95% CI 1.04-1.75). Especially non-screened migrant women had higher risk of positive nodes (OR 2.73, 95% CI 1.43-5.21). Among the subgroup of screened women, we observed no significant differences between migrant and autochthonous patients. Migrant women have lower BC incidence than autochthonous women, but diagnosis was more often at younger age and with unfavorable tumor characteristics. Attending the screening program strongly reduces the latter. Therefore, promotion of participation in the screening program is recommended.

Evaluating a Comprehensive and Cost-Effective Accelerated Breast Health Curriculum in Guyana for Healthcare Providers

The incidence and mortality rate of breast cancer continues to rise in Guyana. One key factor contributing to this issue is that Guyana does not have a national breast cancer screening program nor the resources or infrastructure to support one. As a result, it is important to consider cost-effective solutions that can promote the early detection of breast cancer. The literature suggests a promising intervention could address gaps in frontline healthcare providers' knowledge and understanding of breast health. Providers who receive dedicated curricular training in breast health in conjunction with learning the clinical breast exam (CBE) and ultrasound tend to show an increase in their early detection rates. With this in mind, we sought to evaluate an existing breast health curriculum in Georgetown, Guyana, by measuring provider fund of knowledge before and after the intervention. Over 1 week, sixty-two participants, mostly nursing students, were divided into two groups. Each group participated in the two-and-a-half-day course. Participants were given a pretest assessment and then went through an intensive 8-module course complete with CBE training and ultrasound demonstration before taking a posttest. We found that while only one of the sixty-two participants passed the initial pretest assessment, forty of the sixty-two participants passed the posttest. Statistical analysis showed that the difference in test scores between the pretest and the posttest was statistically significant. While more studies are needed, these findings suggest that focusing on the breast health knowledge of providers in Guyana and other similar countries may be a highly effective yet cost-friendly intervention that could significantly improve early detection rates and ease the breast cancer disease burden.

A brief intervention for improving alcohol literacy and reducing harmful alcohol use by women attending a breast screening service: a randomised controlled trial.

To assess the effectiveness of a brief alcohol intervention for improving awareness of alcohol as a breast cancer risk factor, improving alcohol literacy, and reducing alcohol consumption by women attending routine breast screening. Single-site, double-blinded randomised controlled trial. Maroondah BreastScreen (Eastern Health, Melbourne), part of the national breast cancer screening program. Women aged 40 years or more, with or without a history of breast cancer and reporting any alcohol consumption, who attended the clinic for routine mammography during 5February - 27 August 2021. Active arm: animation including brief alcohol intervention (four minutes) and lifestyle health promotion (three minutes). lifestyle health promotion only. Change in proportion of women who identified alcohol use as a clear risk factor for breast cancer (scaled response measure). The mean age of the 557 participants was 60.3 years (standard deviation, 7.7 years; range, 40-87 years); 455 had recently consumed alcohol (82%). The proportions of participants aware that alcohol use increased the risk of breast cancer were larger at four weeks than at baseline for both the active intervention (65% v 20%; odds ratio [OR], 41; 95% confidence interval [CI], 18-97) and control arms of the study (38% v 20%; OR, 4.9; 95% CI, 2.8-8.8), but the change over time was greater for the active intervention arm (arm × time: P < 0.001). Alcohol literacy also increased to a greater extent in the active than the control arm, but alcohol consumption did not significantly change in either arm. A tailored brief alcohol intervention for women attending breast screening was effective for improving awareness of the increased breast cancer risk associated with alcohol use and alcohol literacy more broadly. Such interventions are particularly important given the rising prevalence of risky drinking among middle-aged and older women and evidence that even very light alcohol consumption increases breast cancer risk. ClinicalTrials.gov, NCT04715516 (prospective; 20January 2021).

Screening outcome for interpretation by the first and second reader in a population-based mammographic screening program with independent double reading.

Double reading of screening mammograms is associated with a higher rate of screen-detected cancer than single reading, but different strategies exist regarding reader pairing and blinding. Knowledge about these aspects is important when considering strategies for future use of artificial intelligence in mammographic screening. To investigate screening outcome, histopathological tumor characteristics, and mammographic features stratified by the first and the second reader in a population based screening program for breast cancer. The study sample consisted of data from 3,499,048 screening examinations from 834,691 women performed during 1996-2018 in BreastScreen Norway. All examinations were interpreted independently by two radiologists, 272 in total. We analyzed interpretation score, recall, and cancer detection, as well as histopathological tumor characteristics and mammographic features of the cancers, stratified by the first and second readers. For Reader 1, the rate of positive interpretations was 4.8%, recall 2.3%, and cancer detection 0.5%. The corresponding percentages for Reader 2 were 4.9%, 2.5%, and 0.5% (P < 0.05 compared with Reader 1). No statistical difference was observed for histopathological tumor characteristics or mammographic features when stratified by Readers 1 and 2. Recall and cancer detection were statistically higher and histopathological tumor characteristics less favorable for cases detected after concordant positive compared with discordant interpretations. Despite reaching statistical significance, mainly due to the large study sample, we consider the differences in interpretation scores, recall, and cancer detection between the first and second readers to be clinically negligible. For practical and clinical purposes, double reading in BreastScreen Norway is independent.