Search

Purpose: Nuclear grade is an important indicator of the biological behaviour of ductal carcinoma in situ (DCIS). De-escalation of treatment has been suggested for low-grade DCIS. Our aim is to estimate the relative rate of progression of DCIS by nuclear grade by analysing the distribution of nuclear grade by detection at initial or subsequent screening. Methods: We asked International Cancer Screening Network sites to complete, based on their screening and clinical databases, an aggregated data file on DCIS detection, diagnosis and treatment. Results: Eleven screening programs reported 5068 screen-detected pure DCIS in nearly 7 million screening tests in women 50–69 years of age. For all programs combined, low-grade DCIS were 20.1% (range 11.4–31.8%) of graded DCIS, intermediate grade 31.0% and high grade 48.9%. Detection rates decreased more steeply from initial to subsequent screening in low compared to high-grade DCIS: the ratios of subsequent to initial detection rates were 0.39 for low grade, 0.51 for intermediate grade, and 0.75 for high grade (p < 0.001). Conclusions: These results suggest that the duration of the preclinical detectable phase is longer for low than for high-grade DCIS. The findings from this large multi-centre, international study emphasize that the management of low-grade DCIS should be carefully scrutinized in order to minimize overtreatment of screen-detected slow-growing or indolent lesions. The high variation by site in the proportion of low grade suggests that further pathology standardization and training would be beneficial. [ABSTRACT FROM AUTHOR]

Background Increased knowledge of breast cancer risk factors provides opportunities to shift from a one-size-fits-all screening programme to a personalised approach, where screening and prevention is based on a woman's risk of developing breast cancer. However, potential implementation of this new paradigm could present considerable challenges which the present review aims to explore. Methods Bibliographic databases were searched to identify studies evaluating potential implications of the implementation of personalised risk-based screening and primary prevention for breast cancer. Identified themes were evaluated using thematic analysis. Results The search strategy identified 5699 unique publications, of which 59 were selected for inclusion. Significant changes in policy and practice are warranted. The organisation of breast cancer screening spans several healthcare delivery systems and clinical settings. Feasibility of implementation depends on how healthcare is funded and arranged, and potentially varies between countries. Piloting risk assessment and prevention counselling in primary care settings has highlighted implications relating to the need for extensive additional training on risk (communication) and prevention, impact on workflow, and professionals' personal discomfort breaching the topic with women. Additionally, gaps in risk estimation, psychological, ethical and legal consequences will need to be addressed. Conclusion The present review identified considerable unresolved issues and challenges. Potential implementation will require a more complex framework, in which a country's healthcare regulations, resources, and preferences related to screening and prevention services are taken into account. However, with the insights gained from the present overview, countries expecting to implement risk-based screening and prevention can start to inventory and address the issues that were identified. [ABSTRACT FROM AUTHOR]

Background: Breast density is known to affect breast cancer risk and screening sensitivity, but it may also be associated with breast cancer survival. The interpretation of results from previous studies on breast density and survival is complicated by the association between detection mode and survival. Here, we studied the effect of breast density on breast cancer-specific survival for different detection modes (screen-detected, interval ≤ 24 or > 24 months, non-participant).Methods: Data from the Nijmegen (Dutch) breast cancer screening programme were used. Women diagnosed with invasive breast cancer between 1975 and 2011 were included. Breast density was assessed visually, based on a dichotomized Wolfe scale: 'fatty breasts' (≤25%) and 'dense breasts' (> 25%). Cox proportional hazard regression was used to obtain hazard ratios (HR).Results: We identified 2742 eligible women, with a breast pattern available for 2233 women. A diagnosis of interval cancer (HR 2.06, 95% CI 1.62-2.61) led to a significantly increased risk of breast cancer death compared with screen-detected cancer. No significant cause-specific survival difference between women with dense and fatty breasts was observed (HR 0.94, 95% CI 0.77-1.15). The hazard was only higher for women with dense breasts among interval cancers ≤24 m (HR 1.07, 95% CI 0.74-1.56). The hazard appeared to be lower for women with dense breasts than for women with fatty breasts among screen-detected (HR 0.77, 95% CI 0.53-1.11) and interval cancers > 24 m (HR 0.80, 95% CI 0.53-1.20). None of the effects were statistically significant.Conclusions: Detection mode is strongly associated with breast cancer death. No clear association is apparent between breast density and breast cancer death, regardless of detection mode. [ABSTRACT FROM AUTHOR]

Objective As breast cancer growth rate is associated with menopause, most screening programmes target mainly women aged 50–74. We studied the association between age at diagnosis and growth rate in this screening-specific age range. Methods We used data from breast cancer patients diagnosed in the screening programme in Nijmegen, the Netherlands. The data were restricted to the screening rounds when analogue mammography was used in both the screening and clinical setting. Growth rate expressed as tumour volume doubling time was based on increasing tumour size in longitudinal series of mammograms. Estimates were based on (a) tumours showing at least two measurable shadows, (b) tumours showing a shadow at detection only (left censored), and (c) tumours showing no growth (right-censored observation). All 293 tumours were consecutively diagnosed invasive ductal breast cancers in participants of the Nijmegen screening programme in the period 2000–2007. Results Depending on the assumptions made on tumour margins and mammographic density, the relation of volume doubling time with age non-significantly varies from a decrease of 3.3% to an increase of 1.4% for each year increase in age at diagnosis (all P-values ≥ 0.18). Applying left censoring on indistinct tumours, the geometric mean volume doubling time was 191 days (95% confidence interval 158–230). Conclusion We found no significant change in growth rate with age in women diagnosed with invasive ductal breast cancer in the screening age range 50–74. This outcome does not support differential screening intervals by age based solely on breast cancer growth rate for this particular group. [ABSTRACT FROM AUTHOR]

Purpose: Our purpose was to compare mammographic positioning quality of new (NR) versus experienced screening radiographers (ER) in the Netherlands.Methods and Materials: Before starting to work in breast screening, NR must complete an education programme including a theoretical course (four days), practical training (six weeks), and a portfolio-review of 50 mammographic screening examinations performed by the radiographer. Furthermore, Dutch screening has an extensive system of quality assurance, including an audit-review of positioning quality of mammograms by ER. We analysed 13,520 portfolio views (NR) and 14,896 audit views (ER) based on pre-specified criteria, e.g., depiction of inframammary angle.Results: Overall positioning was more adequate for NR than ER (CC views: 97% versus 86%, p = 0.00; MLO views: 92% versus 84%, p = 0.00). NR scored better for most of the CC-criteria and showed, for instance, less folds (inadequate: 10% versus 16%, p = 0.00). In contrast, NR encountered more difficulties for MLO views in, for example, depiction of infra-mammary angle (inadequate: 38% versus 34%, p = 0.00). Overall, mammograms from NR were more often considered adequate, because of less severe errors.Conclusion: NR perform better than ER in overall positioning technique. These results stress the need for continuous monitoring and training in breast screening programmes to keep positioning skills up to date.Key Points: • We evaluated positioning quality of new and experienced Dutch screening radiographers. • New radiographers outperform their experienced colleagues in mammographic positioning quality. • New radiographers make less severe errors compared to experienced colleagues. • There is a need for a continuous individual monitoring and feedback system. [ABSTRACT FROM AUTHOR]

Objectives: Differences in breast density between populations may explain part of the variation in regional breast cancer screening performance. This study aimed to determine whether regional differences in breast density distribution are present in the Dutch screening population.Methods: As part of the DENSE trial, mammographic density was measured using a fully-automated volumetric method. The regions in our study were based on the geographic coverage of 14 reading units representing a large part of the Netherlands. General linear models were used.Results: Four hundred eighty-five thousand and twenty-one screening participants with a median age of 60 years were included (2013-2014). The proportion of women with heterogeneously or extremely dense breasts ranged from 32.5% to 45.7% between regions. Mean percent dense volume varied between 6.51% (95% confidence interval [CI]: 6.46-6.55) and 7.68% (95% CI: 7.66-7.71). Age differences could not explain the variation. Socio-economic status (SES) was positively associated with volumetric density in all analyses (low SES: 6.95% vs. high SES: 7.63%; p trend  < 0.0001), whereas a potential association between urbanisation and breast density only became apparent after SES adjustment.Conclusion: There appears to be geographic variation in mammographic density in the Netherlands, emphasizing the importance of including breast density as parameter in the evaluation of screening performance.Key Points: • Mammographic density may affect regional breast cancer screening performance. • Volumetric breast density varies across screening areas. • SES is positively associated with breast density. • Implications of volumetric breast density differences need to be studied further. [ABSTRACT FROM AUTHOR]

Objectives: Our aim was to retrospectively evaluate the results of all audits performed in the past and to assess their value in the quality assurance of the Dutch breast cancer screening programme.Methods: The audit team of the Dutch Reference Centre for Screening (LRCB) conducts triennial audits of all 17 reading units. During audits, screening outcomes like recall rates and detection rates are assessed and a radiological review is performed. This study investigates and compares the results of four audit series: 1996-2000, 2001-2005, 2003-2007 and 2010-2013.Results: The analysis shows increased recall rates (from 0.66%, 1.07%, 1.22% to 1.58%), increased detection rates (from 3.3, 4.5, 4.8 to 5.4 per 1000) and increased sensitivity (from 64.5%, 68.7%, 70.5% to 71.6%), over the four audit series. The percentage of 'missed cancers' among interval cancers and advanced screen-detected cancers did not change (p = 0.4).Conclusions: Our audits not only provide an opportunity for assessing screening outcomes, but also provide moments of self-reflection with peers. For radiologists, an accurate understanding of their performance is essential to identify points of improvement. We therefore recommend a radiological review of screening examinations and immediate feedback as part of an audit.Key Points: • Radiological review and immediate feedback are recommended as part of an audit. • For breast screening radiologists, audits provide moments of self-reflection with peers. • Radiological review of screening examinations provides insights in recall behaviour. • Accurate understanding of radiologists' performance is essential to identify points of improvement. [ABSTRACT FROM AUTHOR]

Purpose: To study the feasibility of a task‐based framework composed of an anthropomorphic breast phantom and mathematical model observers (MOs) for the evaluation of system‐processed mammographic images. Methods: A prototype anthropomorphic breast phantom with inserted gold discs of 0.1 mm and 0.25 mm diameter was imaged with two digital mammography systems (system A and B) at four different dose levels. From the acquired processed and unprocessed images, signal‐present and signal‐absent regions of interest (ROIs) were extracted. The ROIs were evaluated by a non‐pre‐whitening MO with eye filter (NPWE) and by three human observers in a two‐alternative forced‐choice experiment. We compared the human and the MO performance on a simple detection task of the calcification‐like discs in ROIs with and without postprocessing. Proportion of correct responses of the human (PCH) and NPWE (PCNPWE) experiments was calculated and the correlation between the two was analyzed using a mixed‐effect regression model. Correlation results including the goodness of fit (r2) of PCH and PCNPWE for all different parameters investigated were evaluated to determine whether NPWE MO can be used to predict human observer performance. Results: PCH and PCNPWE increased with dose for all conditions investigated (signal size, processing status, and different system). In case of the 0.1 mm discs, for system A, r2 between PCH with PCNPWE was 0.81. For system B, r2 was 0.93. In case of the 0.25 mm discs, r2 in system A was 0.79 and for system B, r2 was 0.82. For the combined parameters investigated, and after excluding the 0.1 mm discs on system A because the results were influenced by aliasing, the overall r2 was 0.81. Image processing did not affect the detectability of calcification‐like signals. No significant difference (P > 0.05) was found between the predicted PCH(pred) by the MO and the PCH for all different conditions. Conclusions: The framework seems promising to be used in objective image quality assessment. It was found to be relatively robust for the range of parameters investigated. However, further optimization of the anthropomorphic breast phantom and investigation of other MOs for a broader range of image quality assessment tasks is needed. [ABSTRACT FROM AUTHOR]

Purpose Model observers (MOs) are of interest in the field of medical imaging to assess image quality. However, before procedures using MOs can be proposed in quality control guidelines for mammography systems, we need to know whether MOs are sensitive to changes in image quality and correlations in background structure. Therefore, as a proof of principle, in this study human and model observer (MO) performance are compared for the detection of calcification-like objects using different background structures and image quality levels of unprocessed mammography images. Method Three different phantoms, homogeneous polymethyl methacrylate, BR3D slabs with swirled patterns (CIRS, Norfolk, VA, USA), and a prototype anthropomorphic breast phantom (Institute of Medical Physics and Radiation Protection, Technische Hochschule Mittelhessen, Germany) were imaged on an Amulet Innovality (FujiFilm, Tokyo, Japan) mammographic X-ray unit. Because the complexities of the structures of these three phantoms were different and not optimized to match the characteristics of real mammographic images, image processing was not applied in this study. In addition, real mammograms were acquired on the same system. Regions of interest (ROIs) were extracted from each image. In half of the ROIs, a 0.25-mm diameter disk was inserted at four different contrast levels to represent a calcification-like object. Each ROI was then modified, so four image qualities relevant for mammography were simulated. The signal-present and signal-absent ROIs were evaluated by a non-pre-whitening model observer with eye filter (NPWE) and a channelized Hotelling observer (CHO) using dense difference of Gaussian channels. The ROIs were also evaluated by human observers in a two alternative forced choice experiment. Detectability results for the human and model observer experiments were correlated using a mixed-effect regression model. Threshold disk contrasts for human and predicted human observer performance based on the NPWE MO and CHO were estimated. Results Global trends in threshold contrast were similar for the different background structures, but absolute contrast threshold levels differed. Contrast thresholds tended to be lower in ROIs from simple phantoms compared with ROIs from real mammographic images. The correlation between human and model observer performance was not affected by the range of image quality levels studied. Conclusions The correlation between human and model observer performance does not depend on image quality. This is a promising outcome for the use of model observers in image quality analysis and allows for subsequent research toward the development of MO-based quality control procedures and guidelines. [ABSTRACT FROM AUTHOR]

Background: Overdiagnosis is the main harm of cancer screening programs but is difficult to quantify. This review aims to evaluate existing approaches to estimate the magnitude of overdiagnosis in cancer screening in order to gain insight into the strengths and limitations of these approaches and to provide researchers with guidance to obtain reliable estimates of overdiagnosis in cancer screening.Methods: A systematic review was done of primary research studies in PubMed that were published before January 1, 2016, and quantified overdiagnosis in breast cancer screening. The studies meeting inclusion criteria were then categorized by their methods to adjust for lead time and to obtain an unscreened reference population. For each approach, we provide an overview of the data required, assumptions made, limitations, and strengths.Results: A total of 442 studies were identified in the initial search. Forty studies met the inclusion criteria for the qualitative review. We grouped the approaches to adjust for lead time in two main categories: the lead time approach and the excess incidence approach. The lead time approach was further subdivided into the mean lead time approach, lead time distribution approach, and natural history modeling. The excess incidence approach was subdivided into the cumulative incidence approach and early vs late-stage cancer approach. The approaches used to obtain an unscreened reference population were grouped into the following categories: control group of a randomized controlled trial, nonattenders, control region, extrapolation of a prescreening trend, uninvited groups, adjustment for the effect of screening, and natural history modeling.Conclusions: Each approach to adjust for lead time and obtain an unscreened reference population has its own strengths and limitations, which should be taken into consideration when estimating overdiagnosis. [ABSTRACT FROM AUTHOR]