Insights from the Breast Cancer Screening Trials: How Screening Affects the Natural History of Breast Cancer and Implications for Evaluating Service Screening Programs |
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Authors: | László Tabár MD Amy Ming‐Fang Yen PhD Wendy Yi‐Ying Wu PhD Sam Li‐Sheng Chen PhD Sherry Yueh‐Hsia Chiu PhD Jean Ching‐Yuan Fann PhD May Mei‐Sheng Ku PhD Robert A Smith PhD Stephen W Duffy MSc Tony Hsiu‐Hsi Chen PhD |
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Affiliation: | 1. Department of Mammography, Central Hospital, Falun, Sweden;2. School of Oral Hygiene, Taipei Medical University, Taipei, Taiwan;3. Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan;4. Department and Graduate Institute of Health Care Management, Chang Gung University, Taoyuan, Taiwan;5. Department of Health Industry Management, College of Healthcare Management, Kainan University, Taoyuan, Taiwan;6. American Cancer Society, Atlanta, Georgia;7. Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK |
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Abstract: | It is desirable to have a strategy for evaluation of breast cancer service screening programs years before the long‐term breast cancer mortality data are available. Since successful mammography screening has a significant impact on two components of the TNM (tumor size, node status, presence or absence of distant metastases) classification system, tumor size and node status, we investigated the effect of the randomized breast screening trials on incidence of advanced stage disease and on the subsequent breast cancer death rate. In the trials that achieved a 20% or greater reduction in advanced stage disease, there was an average breast cancer mortality reduction of 28% among women invited to screening (attenders and nonattenders combined). In the trials that achieved a reduction in advanced stage disease of less than 10%, there was no reduction in breast cancer mortality among women invited to screening. This study provides evidence that the average mortality reduction in all the trials underestimates the true mortality reduction, and that substantially greater breast cancer mortality reductions can be expected in screening programs that are effective in reducing advanced stage breast cancer. In addition, monitoring the incidence of advanced stage breast cancer in an ongoing screening program can provide a sensitive and early indicator of the subsequent mortality from the disease. |
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Keywords: | advanced stage breast cancer early detection mortality screening |
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