Benefits and Harms of Screening Mammography by Comorbidity and Age: A Qualitative Synthesis of Observational Studies and Decision Analyses

We conducted a systematic review to assess the quality and limitations of published studies examining benefits and harms of screening mammography in relation to comorbidity and age. We searched MEDLINE and EMBASE from January 1980 through June 2013 for studies that examined benefits or harms of screening mammography in women aged 65 years or older in relation to comorbidity. For each study, we extracted data regarding setting, design, quality, screening schedule, measure of comorbidity, and estimates of benefits and/or harms. We reviewed 1760 titles, identifying 7 articles that met the inclusion criteria: prospective cohort (two studies), retrospective cohort (two studies), and decision analyses (three studies). No randomized controlled trials were identified. At least one measure of life expectancy or reduction in the risk of breast cancer death as a marker of benefit was examined in four studies, whereas three studies addressed the harms of screening mammography, including false-positive results. Both cohort studies and decision analyses showed that screening benefits decreased with increasing age and comorbidity burden. The limited evidence currently available suggests that, apart from older women with severe comorbidity, women 65 and older may experience improvements in life expectancy from screening. Given the potential for harm, it is unclear whether the magnitude of the benefit is sufficient to warrant regular screening. Women, clinicians and policymakers should consider these factors in deciding whether continue screening.