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Otto S.J.,Rotterdam University | Fracheboud J.,Rotterdam University | Verbeek A.L.M.,Radboud University Nijmegen | Boer R.,Rotterdam University | And 5 more authors.
Cancer Epidemiology Biomarkers and Prevention | Year: 2012

Background: Because the efficacy of mammography screening had been shown in randomized controlled trials, the focus has turned on its effectiveness within the daily practice. Using individual data of women invited to screening, we conducted a case-control study to assess the effectiveness of the Dutch population-based program of mammography screening. Methods: Cases were women who died from breast cancer between 1995 and 2003 and were closely matched to five controls on year of birth, year of first invitation, and number of invitations before case's diagnosis. ORs and 95% confidence intervals (CI) for the association between attending either of three screening examinations prior to diagnosis and the risk of breast cancer death were calculated using conditional logistic regression and corrected for self-selection bias. Results: We included 755 cases and 3,739 matched controls. Among the cases, 29.8% was screen-detected, 34.3% interval-detected, and 35.9% never-screened. About 29.5% of the never-screened cases had stage IV tumor compared with 5.3% of the screen-detected and 15.1% of the interval-detected cases. The OR (95% CIs), all ages (49-75 years), was 0.51 (0.40-0.66) and for the age groups 50-69, 50-75, and 70-75 years were 0.61 (0.47-0.79), 0.52 (CI 0.41-0.67), and 0.16 (0.09-0.29), respectively. Conclusion: The study provides evidence for a beneficial effect of early detection by mammography screening in reducing the risk of breast cancer death among women invited to and who attended the screening. Impact: This is the first case-control study that accurately accounts for equal screening opportunity for both cases and matched controls by number of invitations before case's diagnosis. ©2011 American Association for Cancer Research. Source

Van Luijt P.A.,Erasmus MC | Fracheboud J.,Erasmus MC | Heijnsdijk E.A.M.,Erasmus MC | Den Heeten G.J.,National Expert and Training Center for Breast Cancer Screening | De Koning H.J.,Erasmus MC
European Journal of Cancer | Year: 2013

Purpose To critically evaluate and confirm previous results regarding the diagnostic accuracy of digital mammography screening (DM), compared to screen-film mammography (SFM) in the whole Dutch screening programme, in the period of 2004-2010, during which a full transition from SFM to DM was made. Materials and methods 1.5 million DM and 4.6 million SFM were read in the Dutch national breast cancer screening programme in the period of 2004-2010. We evaluated recall rate, detection rate, positive predictive value and tumour-size distribution for younger and older women, for first time participants and women having a timely subsequent screen. We compared DM screens read by radiologists reading DM and SFM (DM-group) to SFM screens read by these radiologists (SFM-group) and to SFM screens read by radiologists reading only SFM (SFMonly-group). Results Recall rate was 2.0% (95% confidence interval (C.I.): 2.0; 2.1) in the DM-group, compared to 1.6% (95% C.I.: 1.6; 1.6) in the SFM-group and 1.6% (95% C.I.: 1.5; 1.6) in the SFM only-group. The overall detection rates were 5.9/1000 screens (95% C.I.: 5.7; 6.0) in the DM-group, 5.1/1000 screens (95% C.I.: 5.0; 5.2) in the SFM-group and 5.0/1000 screens (95% C.I.: 5.0; 5.1) in the SFM only-group. Detection rate rose most markedly in younger women (age 49-54) from 4.0/1000 screens to 5.1/1000 screens (p-value < 0.001). Positive predictive value (PPV) in DM rose from 18.4% (95% C.I.: 14.6; 23.1) in 2004 to 32.5% (95% C.I.: 31.7; 33.2) in 2010. Detection rate rose in SFM-group from 5.0/1000 screens (95% C.I.: 4.7; 5.3) in 2004 to 5.5/1000 screens (95% C.I.: 5.2; 5.7) in 2010. Detection rate in DM-group rose mostly due to ductal carcinoma in situ (DCIS) detection especially in younger women/first screens. The proportion of T1a tumours was significantly higher in DM-group; otherwise size distribution did not change significantly for invasive carcinoma. Recall rates were variable between different screening regions. Conclusion In accordance to previous, smaller, studies, we can confirm that DM has a higher detection rate compared to SFM, at the cost of a higher recall rate and lower PPV. More DCIS and a higher fraction of very small tumours were detected with DM, which has positive consequences for the stage shift as a result of mass screening. © 2013 Elsevier Ltd. All rights reserved. Source

Kallenberg M.G.J.,Radboud University Nijmegen | Van Gils C.H.,University Utrecht | Lokate M.,University Utrecht | Den Heeten G.J.,National Expert and Training Center for Breast Cancer Screening | Karssemeijer N.,Radboud University Nijmegen
Physics in Medicine and Biology | Year: 2012

For the acquisition of a mammogram, a breast is compressed between a compression paddle and a support table. When compression is applied with a flexible compression paddle, the upper plate may be tilted, which results in variation in breast thickness from the chest wall to the breast margin. Paddle tilt has been recognized as a major problem in volumetric breast density estimation methods. In previous work, we developed a fully automatic method to correct the image for the effect of compression paddle tilt. In this study, we investigated in three experiments the effect of paddle tilt and its correction on volumetric breast density estimation. Results showed that paddle tilt considerably affected accuracy of volumetric breast density estimation, but that effect could be reduced by tilt correction. By applying tilt correction, a significant increase in correspondence between mammographic density estimates and measurements on MRI was established. We argue that in volumetric breast density estimation, tilt correction is both feasible and essential when mammographic images are acquired with a flexible compression paddle. © 2012 Institute of Physics and Engineering in Medicine. Source

Broeders M.J.M.,National Expert and Training Center for Breast Cancer Screening | Broeders M.J.M.,Radboud University Nijmegen | Den Heeten G.J.,National Expert and Training Center for Breast Cancer Screening | Den Heeten G.J.,Radboud University Nijmegen
Medical Physics | Year: 2013

Purpose: In x-ray mammography, flattening of the breast improves image quality and reduces absorbed dose. Current mammographic compression guidelines are based on applying a standardized force to each breast. Because breast size is not taken into consideration, this approach leads to large variations in applied pressure (force applied per unit contact area). It is the authors' hypothesis that a pressure-controlled compression protocol, which takes contact area into account, (1) improves standardization across the population in terms of physiological conditions in the compressed breast (blood pressure), and (2) reduces discomfort and pain, particularly the number of severe pain complaints, (3) with limited effects on image quality and absorbed glandular dose (AGD). Methods: A prospective observational study including 291 craniocaudal (CC) and 299 mediolateral oblique (MLO) breast compressions in 196 women following the authors' hospital's standard compression protocol with 18 decanewton (daN) target force was performed. Breast thickness, applied force, area of contact between breast and compression paddle, and mean pressure were recorded during the entire compression. Pain scores before and after breast compressions were obtained using an 11-point numerical rating scale (NRS). Scores of 7 and higher were considered to indicate severe pain. The authors analyzed differences between the CC and MLO compressions, correlation coefficients (ρ) between compression parameters, and odds-ratios (OR) for all parameters as possible predictors for experiencing severe pain using multivariate logistic regression. The observed data were used in two models to estimate what breast thickness, required force, and pain score would be for pressure-controlled compression protocols with target pressures ranging from 4 to 28 kilopascal (kPa). For a selection of 79 mammograms having a 10% or more thickness difference with respect to the prior mammogram, the authors performed a retrospective observer study to assess whether such thickness differences have significant effects on image quality or AGD. Results: In a standard 18 daN force-controlled compression protocol, the authors observed an average pressure of 21.3 kPa ± 54% standard deviation for CC compressions and 14.2 kPa ± 32% for MLO compressions. Women with smaller breasts endured higher pressures and experienced more pain, as indicated by a significant negative correlation (ρ = -0.19, p < 0.01) between contact area and pain score. Multivariate regression showed that contact area is a strong and significant predictor for severe pain (ORNRS≥7 CC =0.10/dm2, p < 0.05), as is the case with any pain already present before compression (ORNRS≥7 CC =1.61 per NRS-point, p < 0.05). Model estimations showed that mammographic breast compression with a standardized pressure of 10 kPa, corresponding with normal arterial blood pressure, may significantly reduce the number of severe pain complaints with an average increase in breast thickness of 9% for small breasts and 2% for large breasts. For an average 16.5% thickness difference in prior-current mammogram pairs, the authors found no differences in image quality and AGD Conclusions: Model estimations and an observer study showed that pressure-controlled mammographic compression protocols may improve standardization and reduce discomfort with limited effects on image quality and AGD. © 2013 American Association of Physicists in Medicine. Source

Bluekens A.M.J.,National Expert and Training Center for Breast Cancer Screening | Holland R.,National Expert and Training Center for Breast Cancer Screening | Karssemeijer N.,Radboud University Nijmegen | Broeders M.J.M.,National Expert and Training Center for Breast Cancer Screening | And 2 more authors.
Radiology | Year: 2012

Purpose: To compare screen-film mammography with digital mammography in a breast cancer screening program, with a focus on the clinical relevance of detected cancers. Materials and Methods: The study was approved by the regional medical ethics review board. Informed consent was not required. Before the nationwide transition to digital mammography in the Dutch biennial screening program, the performance of digital mammography was studied in three screening regions. For initial screening examinations, mediolateral oblique and craniocaudal views were obtained of each breast. In subsequent examinations, the mediolateral oblique view was standard. A craniocaudal view was added if indicated. Screening outcomes obtained with screen-film mammography and digital mammography, including radiologic and pathologic characteristics, were compared for initial and subsequent examinations. Results: A total of 1198493 screening examinations were performed between 2003 and 2007. Recall was indicated in 18896 cases (screen-film mammography: 2.6% at initial examinations, 1.3% at subsequent examinations; digital mammography: 4.4% at initial examinations, 2.1% at subsequent examinations; P < .001 for both). Breast cancer was diagnosed in 6410 women (detection rate per 1000 women with screen-film mammography: 5.6 at initial examinations, 5.2 at subsequent examinations; detection rate per 1000 women with digital mammography: 6.8 at initial examinations, 6.1 at subsequent examinations; P = .02 and P < .001, respectively). Digital mammography depicted significantly more ductal carcinoma in situ (DCIS) lesions, irrespective of screening round. Invasive carcinoma was detected significantly more often in subsequent examinations, particularly when associated with microcalcifications (P = .047). The distribution of the histopathologic differentiation grades for DCIS and invasive carcinoma were similar with both modalities. However, with digital mammography more high-grade DCIS lesions were detected at subsequent examinations (P = .013). Conclusion: In a population-based breast screening program, the performance of digital mammography in the detection of DCIS and invasive carcinoma was substantially better than that of screen-film mammography. There is no sign of an increase in detection of low-grade DCIS lesions-indicative of possible overdiagnosis-with digital breast cancer screening. Rather, digital mammography appears to add to the detection of high-grade DCIS. © RSNA, 2012. Source

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