Screening mammography in older women: the balance between appropriate use and overuse

Abstract

263 ISSN 1758-1923 10.2217/BMT.13.24 © 2013 Future Medicine Ltd Breast Cancer Manage. (2013) 2(4), 263–265 The incidence of female breast cancer gen‐ erally increases with age, with a median age of 61 years at the time of diagnosis. Women aged 65 years and older comprise approximately 35% of incident breast can‐ cer cases and 57% of breast cancer deaths [1]. The likelihood of death from breast cancer increases with advanced stage and larger tumor size at diagnosis. An impor‐ tant strategy to reduce such deaths is to screen asymptomatic women with mam‐ mography in order to detect and treat breast cancer in its preclinical stage and improve survival. However, ubiquitous mammographic screening among older women may not confer the expected ben‐ efit, but instead may result in unintended harms. For example, there is at least a 4‐year lag between screen‐detected breast cancer and onset of clinical symptoms for women aged 65–74 years [2]. Mammo‐ graphy trials found no survival difference between screened and unscreened women before 7 years of follow‐up for women aged 65–74 years [3]. In older women with lim‐ ited life expectancy, the delayed screening benefit does not have sufficient time to emerge because of competing risks. In fact, such women may be exposed to immediate physical and psychological harms caused by false‐positive results, invasive diagnostic tests, and overdiagnosis and overtreatment of breast cancer that otherwise would not have been diagnosed and treated in their lifetime [4,5]. High‐quality screening mam‐ mography services need to strike a balance between appropriate use and overuse; that is, they must screen older women who have a long enough life expectancy to benefit and avoid screening those with limited life expectancy. Both underuse and overuse of screen‐ ing mammography are evident among older women. Current cancer screening guidelines generally set age limits in their recommendations. For example, the US Preventive Services Task Force recom‐ mends regular screening mammography for women aged 50–74 years and individu‐ alized screening decisions for those aged 75 years and older [6]. It was estimated that, among women aged 75–90 years, approxi‐ mately 80% had an estimated life expec‐ tancy of 7 or more years and 60% had a life expectancy of 10 or more years [7,8]. With the rapid growth of the aging population, the proportion of such healthy, very old persons is expected to increase accordingly.