A true screening environment for review of interval breast cancers: pilot study to reduce bias.

PURPOSE: To retrospectively assess the feasibility of an uninformed review process to evaluate interval breast cancers and to compare the number of false-negative cancers detected at uninformed review with the number detected at standard informed review. MATERIALS AND METHODS: Institutional review board approval was obtained for this retrospective study, and informed consent was waived. Mammograms showing interval cancer were included in the daily work of radiologists in a high-volume screening center. Each of three experienced radiologists read studies in the normal screening environment, without knowledge that identifiers had been changed to conceal the fact that studies were not current (ie, uninformed review). Results were compared with the standard review procedure, in which mammograms showing interval cancers were mixed with normal mammograms and read in a panel of 17-20 interval cancers per 80 normal studies by radiologists who were aware that they were participating in a review process (ie, informed review). RESULTS: Of 21 interval cancers, six (29%) were interpreted as positive more often by the informed radiologists than by the uninformed radiologists. For 14 (67%) cancers, there was no difference in detection rate between the two groups, and one cancer (5%) was seen by one of the uninformed radiologists but by none of the informed radiologists. The screening environment review process was found to be feasible at the low volumes tested. CONCLUSION: The number of false-negative cancers was higher in the informed review than in the uninformed review. This result suggests that bias exists with the informed review process.

Invasive lobular carcinoma of the breast: mammographic characteristics and computer-aided detection.

PURPOSE: To characterize the mammographic appearance of invasive lobular carcinoma in a large series of screening-detected consecutive breast cancers and to evaluate the ability of a computer-aided detection system to mark these carcinomas. MATERIALS AND METHODS: Investigators used the Breast Imaging Reporting and Data System lexicon to characterize lesions as part of a retrospective review of 90 screening mammographic examinations that led to biopsy-proved diagnosis of 94 invasive lobular carcinoma lesions. The 40 available prior mammographic examinations (obtained 9-24 months earlier) were also reviewed to characterize any visible findings. The results of a computer-aided detection analysis were compared with the images, and the sensitivity of the algorithm was calculated for correct detection of the lesions. RESULTS: Fifty-six (60%) of 94 lesions manifested as masses, of which 40 (71%) were described as irregular and spiculated; 20 (21%) of 94, as architectural distortions; and the remainder, 18 (20%), as either asymmetric densities or calcifications. On the screening mammograms showing biopsy-proved cancers, the sensitivity of the computer-aided detection system was 86 (91%) of 94 lesions. Thirty-one of the 40 prior mammograms showed retrospectively visible findings, and 24 (77%) of 31 were marked by the computer-aided detection system. CONCLUSION: Spiculated masses and architectural distortions are the predominant appearances of invasive lobular carcinoma, and a computer-aided detection system correctly marked a high percentage of invasive lobular carcinoma lesions.