Abstract
Differentiating which screen-detected breast cancers have no detrimental health effect versus those that will progress to a more advanced stage is not possible. There is no consistent method for predicting which untreated cancers would be lethal or increase in size rapidly, or the converse. More advanced stage at diagnosis of clinically detected cancers versus mammogram-detected cancers results in more aggressive surgery, chemotherapy, and radiation therapy, with a lower 5-year survival [ 1 Malmgren J.A. Parikh J. Atwood M.K. Kaplan H.G. Impact of mammography detection on the course of breast cancer in women aged 40-49 years. Radiology. 2012; 262: 797-806 Crossref PubMed Scopus (74) Google Scholar ]. Earlier stage cancer at diagnosis correlates with reduced breast cancer mortality [ 2 Saadatmand S. Bretveld R. Siesling S. Tilanus-Linthorst M.M. Influence of tumour stage at breast cancer detection on survival in modern times: population based study in 173,797 patients. BMJ. 2015; 351: h4901 Crossref PubMed Scopus (214) Google Scholar ]. This study demonstrates that a program based on annual mammography beginning at the age of 40 results in a smaller percentage of higher-stage cancers and resultant lower estimated mortality, versus programs based on less-frequent screening intervals and starting at a later age. Demonstration of Classic Screening Biases, Not Additional Benefit of Annual Over Biennial ScreeningJournal of the American College of RadiologyVol. 15Issue 10PreviewWe support the need to carefully evaluate different starting and stopping ages and different intervals for programs of screening mammography. Dr Patel’s analysis, however, is fatally flawed by classic screening biases—length bias, the extreme of which is called overdiagnosis bias, and lead time bias. These biases have long been known to invalidate comparisons of 5-year survival rates between screened and unscreened women [1-4]. Taking the complement of 5-year survival, by subtraction from 100% to produce 5-year mortalities, does nothing to overcome these biases. Full-Text PDF
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