Annual screening mammography results in a greater reduction in mortality compared to biennial screening [8]. In women 40 to 84 years of age, annual screening reduces mortality by 40%, compared to a 32% reduction for biennial screening [32]. With regular screening, interval breast cancers do occur with a higher frequency in women undergoing biennial or triennial screening compared to annual screening. The sensitivity of mammography is decreased in some groups of women, including those with dense breasts [40]. Dense breast tissue decreases the sensitivity of mammography [26] and is an independent risk factor for developing breast cancer [27]. Compared to average breast density (near the threshold between heterogeneously dense and scattered areas of fibroglandular density), the relative risks for developing breast cancer are 1.2 for heterogeneously dense and 2.1 for extremely dense breasts [28]. Some health care providers may therefore consider women with extremely dense breasts to no longer be average risk. Given the limitations of mammography and to minimize interval cancers, supplemental screening modalities have been investigated in women at intermediate risk. Because screening mammography decreases breast cancer mortality, screening mammography or screening DBT is still performed in women undergoing supplemental screening studies [3,8,35]. Rather than supplementing screening mammography with additional imaging modalities, some have suggested limiting women offered screening mammography based upon individual patient risk assessed by various risk models, breast density, or genetic information such as single-nucleotide polymorphisms. However, the randomized controlled trials demonstrating mortality reduction and most large-scale observational studies enrolled women based upon age and geographic location, not individual patient risk factors.
Female Breast Cancer Screening. Annual screening mammography results in a greater reduction in mortality compared to biennial screening [8]. In women 40 to 84 years of age, annual screening reduces mortality by 40%, compared to a 32% reduction for biennial screening [32]. With regular screening, interval breast cancers do occur with a higher frequency in women undergoing biennial or triennial screening compared to annual screening. The sensitivity of mammography is decreased in some groups of women, including those with dense breasts [40]. Dense breast tissue decreases the sensitivity of mammography [26] and is an independent risk factor for developing breast cancer [27]. Compared to average breast density (near the threshold between heterogeneously dense and scattered areas of fibroglandular density), the relative risks for developing breast cancer are 1.2 for heterogeneously dense and 2.1 for extremely dense breasts [28]. Some health care providers may therefore consider women with extremely dense breasts to no longer be average risk. Given the limitations of mammography and to minimize interval cancers, supplemental screening modalities have been investigated in women at intermediate risk. Because screening mammography decreases breast cancer mortality, screening mammography or screening DBT is still performed in women undergoing supplemental screening studies [3,8,35]. Rather than supplementing screening mammography with additional imaging modalities, some have suggested limiting women offered screening mammography based upon individual patient risk assessed by various risk models, breast density, or genetic information such as single-nucleotide polymorphisms. However, the randomized controlled trials demonstrating mortality reduction and most large-scale observational studies enrolled women based upon age and geographic location, not individual patient risk factors.