2933. Assessment of Cancers Detected by Digital Breast Tomosynthesis: Comparison by Patient Age and Breast Density
Authors * Denotes Presenting Author
  1. Jaskiran Grewal *; Yale School of Medicine
  2. Maryam Etesami; Yale School of Medicine
  3. Liane Philpotts; Yale School of Medicine
Although digital breast tomosynthesis (DBT) has been shown to have advantages in reducing false positive recalls in screening mammography, the increase in cancers detected compared with digital mammography (DM) has been more variable. Breast density is a major factor limiting the sensitivity of mammography. The types of cancers detected in DBT screening is an area needing more investigation. The purpose of this study was to assess the subtypes of cancers detected over 10 years of DBT screening by the important variable of breast density.

Materials and Methods:
A retrospective search of electronic medical records from a tertiary academic hospital and 3 satellite facilities identified breast cancers with over a decade of screening DBT mammography (examinations August 1, 2011 through July 31, 2021). Data collected included comprehensive demographic, imaging (including breast density) and pathology information. Invasive cancers 2 cm or larger, HER2-positive or triple-negative tumors > 10 mm, one or more positive axillary nodes or distant organ spread were considered advanced cancers.

A total of 1265 cancers were detected by DBT (for a cancer detection rate of 5.3 per 1000). Of the cancers detected, 454 (36%) were in women with dense tissue and 811 (64%) in nondense. The ratio of invasive to in situ cancers were similar in both groups: dense 76%:24% (347:107) versus nondense 77%:23 (621:190). Importantly, the rate of advanced cancers was similar in both groups: 113/347 (32.56%) versus 202/621 (32.52%), respectively. Rates of advanced cancers were similar for each density subgroup (A,B,C,D) for all except the extremely dense category: A, 16/47 (34%), B 190/572 (33%), C 108/329 (33%), D 4/18 (22%), possibly due to low numbers.

DBT detects similar subtypes of breast cancers regardless of breast density with a similar rate of advanced cancers found in dense and nondense tissue. This supports the use of DBT technology in mammography screening for all women.