"CADEAT": considerations on the use of CAD (computer-aided diagnosis) in mammography

Is single reading with computer-aided detection (CAD) as good as double reading in mammography screening? A systematic review

BACKGROUND

In accordance with European guidelines, mammography screening comprises independent readings by two breast radiologists (double reading). CAD (computer-aided detection) has been suggested to complement or replace one of the two readers (single reading + CAD).The aim of this systematic review is to address the following question: Is the reading of mammographic x-ray images by a single breast radiologist together with CAD at least as accurate as double reading?

METHODS

The electronic literature search included the databases Pub Med, EMBASE and The Cochrane Library. Two independent reviewers assessed abstracts and full-text articles.

RESULTS

1049 abstracts were identified, of which 996 were excluded with reference to inclusion and exclusion criteria; 53 full-text articles were assessed for eligibility. Finally, four articles were included in the qualitative analysis, and one in a GRADE synthesis.

CONCLUSIONS

The scientific evidence is insufficient to determine whether the accuracy of single reading + CAD is at least equivalent to that obtained in standard practice, i.e. double reading where two breast radiologists independently read the mammographic images.

Breast cancer: missed interval and screening-detected cancer at full-field digital mammography and screen-film mammography-- results from a retrospective review

PURPOSE

To compare the percentages and mammographic features of cancers missed at full-field digital mammography (FFDM) and screen-film mammography (SFM) in women who participated in the Norwegian Breast Cancer Screening Program in 2002-2008.

MATERIALS AND METHODS

Social Science Data Services approval was obtained; the requirement for informed consent was waived. Cases were all the interval and screening-detected cancers from 35 127 FFDM and 52 444 SFM examinations in two Norwegian counties. Prior and diagnostic FFDM examinations of 49 interval and 86 screening-detected breast cancers were reviewed by four breast radiologists and compared with a review of SFM examinations of 81 interval and 123 screening-detected cancers. Cancers were classified as missed or true, mammographic features were described, percentages were compared by using the χ(2) or Fisher exact test, and 95% confidence intervals (CIs) were calculated.

RESULTS

The percentages of interval and screening-detected cancers missed at FFDM and SFM did not differ significantly. (interval cancers missed: 33% [16 of 49] at FFDM vs 30% [24 of 81] at SFM [P = .868]; screening-detected cancers missed: 20% [17 of 86] at FFDM vs 21% [26 of 123] at SFM [P = .946]). Asymmetry was present in 27% (95% CI: 13.3%, 45.5%) of prior mammograms of cancers missed at FFDM and 10% (95% CI: 3.3%, 21.8%) of those missed at SFM (P = .070). Calcifications were observed in 18% (95% CI: 7.0%, 35.5%) of the cancers missed at FFDM and 34% (95% CI: 21.2%, 48.8%) of those missed at SFM (P = .185). Average mammographic tumor size of missed cancers manifesting as masses was 10.4 mm at FFDM and 13.6 mm at SFM (P = .036).

CONCLUSION

The use of FFDM has not reduced the challenge of missed cancers. Cancers missed at FFDM tend to have different mammographic features than those missed at SFM.

CAD e mamografia: por que usar esta ferramenta?

A mamografia representa o melhor método de detecção precoce do câncer de mama, porém cerca de 10% a 30% das lesões mamárias são perdidas no rastreamento, devido a limitações próprias dos observadores humanos. A detecção auxiliada por computador (computer-aided detection - CAD) é uma tecnologia relativamente nova que tem sido implementada em alguns serviços de mamografia, com o intuito de prover uma dupla leitura. Estudos clínicos têm demonstrado que o CAD aumenta a sensibilidade de detecção do câncer da mama, por radiologistas, em até 21%. Um sistema CAD é útil em situações em que exista alta variabilidade interobservador, falta de observadores treinados, ou na impossibilidade de se realizar a dupla leitura com dois ou mais radiologistas. O objetivo desta revisão está baseado na necessidade de atualizar a comunidade médica acerca desta ferramenta, como um método auxiliar, quantitativo, não operador-dependente, e que visa a melhorar a qualidade do diagnóstico do câncer de mama.