Implications of Overdiagnosis: Impact on Screening Mammography Practices

Abstract

This review article explores the issue of overdiagnosis in screening mammography. Overdiagnosis is the screen detection of a breast cancer, histologically confirmed, that might not otherwise become clinically apparent during the lifetime of the patient. While screening mammography is an imperfect tool, it remains the best tool we have to diagnose breast cancer early, before a patient is symptomatic and at a time when chances of survival and options for treatment are most favorable. In 2015, an estimated 231,840 new cases of breast cancer (excluding ductal carcinoma in situ) will be diagnosed in the United States, and some 40,290 women will die. Despite these data, screening mammography for women ages 40-69 has contributed to a substantial reduction in breast cancer mortality, and organized screening programs have led to a shift from late-stage diagnosis to early-stage detection. Current estimates of overdiagnosis in screening mammography vary widely, from 0% to upwards of 30% of diagnosed cancers. This range reflects the fact that measuring overdiagnosis is not a straightforward calculation, but usually one based on different sets of assumptions and often biased by methodological flaws. The recent development of tomosynthesis, which creates high-resolution, three-dimensional images, has increased breast cancer detection while reducing false recalls. Because the greatest harm of overdiagnosis is overtreatment, the key goal should not be less diagnosis but better treatment decision tools. (Population Health Management 2015;18:S3-S11)

How Can Advanced Imaging Be Used to Mitigate Potential Breast Cancer Overdiagnosis?

“…This effort will likely require a combination of advanced imaging and molecular markers to help physicians differentiate life-threatening tumors that need treatment from those less aggressive cancers that may be followed or treated less aggressively. 22 One area of active investigation is the combined use of multiparametric MRI and tumor molecular biomarkers to improve management of low-grade DCIS with the goal of reducing overtreatment of low-risk lesions.…”

Plasma lipidomics profiling identified lipid biomarkers in distinguishing early-stage breast cancer from benign lesions

“…The rate of over-diagnosis of breast cancer in screening mammography is wide, from 0% to upwards of 30% [3]. Women with abnormal screening mammograms undergo additional expensive magnetic resonance imaging (MRI) and tissue sampling (by fine-needle aspiration, core biopsy, or excisional biopsy).…”

Women’s Awareness of and Responses to Messages About Breast Cancer Overdiagnosis and Overtreatment

“…2 Overdiagnosis typically gives rise to overtreatment, defined as the unnecessary use of tests and treatments. Although it is difficult to pinpoint just how common cancer overdiagnosis is—its prevalence must be estimated indirectly, based on the results of large-scale screening programs and population studies 3 —there is growing expert consensus that the phenomenon is real and may require a reevaluation of aggressive screening strategies. For example, a recent Danish study estimated that one-third of breast cancers detected by mammography represent overdiagnosis.…”