The recent article by Carter et al. titled “Insights Into Breast Cancer Screening: A Computer Simulation of Two Contemporary Screening Strategies” [1] completely ignores the screening strategy shown to maximize benefits, that of annual mammography screening starting at 40 years old [2]. The authors conclude that the American Cancer Society (ACS) hybrid protocol is preferred to the U.S. Preventive Services Task Force (USPSTF) biennial protocol in most of their scenarios, a finding that is not surprising given that the ACS protocol is a more intensive screening protocol compared with that of the USPSTF. Not including the annual screening regimen recommended by the National Comprehensive Cancer Network, the American College of Radiology, and the Society of Breast Imaging is a major omission, particularly for a publication in a radiology journal.

The authors place a high degree of emphasis on overdiagnosis in their article, from introduction to discussion. First, the magnitude of overdiagnosis can only be estimated, not measured, with estimates varying widely depending on whether key confounding variables are taken into account. Whereas the authors use ranges of values in other aspects of their models, overdiagnosis is given a fixed rate. The high estimate of 30% chosen by the authors is based on studies that do not adjust for key confounding variables, whereas studies that make such adjustments estimate that overdiagnosis occurs in less than 10% of cases [3]. More importantly, overdiagnosis is not a valid reason to recommend biennial versus annual screening or to delay start of screening until 50 years old because changing the age to start screening and changing screening intervals have absolutely no impact on overdiagnosis. Cancers identified at screening mammography neither disappear nor regress if untreated [4]. Therefore, if a 40-year-old woman harboring an overdiagnosed cancer delays the start of screening until she is 45 or 50 years old, the overdiagnosed cancer will simply be found 5 or 10 years later. Similarly, an overdiagnosed cancer found at annual screening will still be found 1 year later if screening is biennial. Thus, age of onset and frequency of screening do not impact the amount of overdiagnosis [4]. As such, overdiagnosis should not be a factor in formulating age-of-onset and screening-interval guidelines.

Women need to consider the balance of benefits and risks when deciding on a screening strategy to follow. Annual screening mammography starting at 40 years old is not only a mainstream screening strategy but also the strategy that maximizes breast cancer mortality reduction, life years gained, and the opportunity to receive less invasive, less toxic breast cancer treatment [2], the very benefits sought and highly valued by women who choose to be screened.