Screening mammography detected cancers: Sensitivity of a computer-aided detection system applied to full-field digital mammograms

Purpose: To retrospectively evaluate the sensitivity of the performance of a computer-aided detection ( CAD) system applied to full-field digital mammograms for detection of breast cancers in a screening group, with histologic findings as the reference standard. Materials and Methods: This study had institutional review board approval, and patient informed consent was waived. A commercially available CAD system was applied to the digital mammograms of 103 women ( mean age, 51 years; range, 35 - 69 years) with 103 breast cancers detected with screening. Sensitivity values of the CAD system according to mammographic appearance, breast composition, and histologic findings were analyzed. Normal mammograms from 100 women ( mean age, 54 years; age range, 35 - 75 years) with no mammographic and clinical abnormality during 2- year follow- up were used to determine false- positive CAD system marks. Differences between the cancer detection rates in fatty and dense breasts for the CAD system were compared by using the X-2 test. Results: The CAD system correctly marked 99 ( 96.1%) of 103 breast cancers. The CAD system marked all 44 breast cancers that manifested as microcalcifications only, all 23 breast cancers that manifested as a mass with microcalcifications, and 32 ( 89%) of 36 lesions that appeared as a mass only. The sensitivity of the CAD system in the fatty breast group was 95% ( 59 of 62) and in the dense breast group was 98% ( 40 of 41) ( P = .537). The CAD system correctly marked all 31 lesions of ductal carcinoma in situ ( DCIS), all 22 lesions of invasive ductal carcinoma with DCIS, the single invasive lobular carcinoma lesion, and 45 ( 92%) of 49 lesions of invasive ductal carcinoma. On normal mammograms, the mean number of false-positive marks per patient was 1.80 ( range, 0 - 10 marks; median, 1 mark). Conclusion: The CAD system can correctly mark most (96.1%) asymptomatic breast cancers detected with digital mammographic screening, with acceptable false- positive marks (1.80 per patient). (c) RSNA, 2007.