Mammography: Integrating 2D, 3D May Improve Cancer Detection

Troy Brown

April 24, 2013

Integrated 2-dimensional (2D) and 3D mammography may improve breast cancer detection and reduce the number of false-positive recalls, according to a prospective comparative study of 7292 women.

Nehmat Houssami, MBBS, PhD, an associate professor and principal research fellow in the Screening and Test Evaluation Program at the School of Public Health, Sydney Medical School, University of Sydney, Australia, and colleagues present their findings in an article published online April 25 in the Lancet.

The study included asymptomatic women aged 48 years or older who were screened from August 2011 to June 2012 in Trento and Verona, Italy. Screen-reading was done in 2 sequential phases: 2D only and integrated 2D and 3D mammography. Participants were recalled on the basis of positive mammography at either of the screen reads.

The researchers include data for 7294 screens because 2 participants had bilateral cancer. Overall, the investigators found 59 breast cancers (52 invasive cancers and 7 ductal carcinoma in situ cancers) in 57 women. Of the 59 cancers, the investigators saw 39 by both 2D and integrated 2D and 3D screening. They uncovered another 20 cancers by integrated 2D and 3D screening only (P < .0001).

The researchers detected cancer at rates of 5.3 cancers per 1000 screens (95% confidence interval [CI], 3.8 - 7.3) with 2D only and 8.1 cancers per 1000 screens (95% CI, 6.2 - 10.4) with integrated 2D and 3D screening. Integrated 2D and 3D mammography had an incremental cancer detection rate of 2.7 cancers per 1000 screens (95% CI, 1.7 - 4.2), or 33.9% (95% CI, 22.1% - 47.4%) of the cancers identified in the study population. The incremental cancer detection rate was similar in low-density vs high-density groups (2.8 per 1000 vs 2.5 per 1000; P = .84).

There were fewer false-positive screens with integrated 2D and 3D screening. False-positive recalls occurred in 395 screens (5.5%; 95% CI, 5.0% - 6.0%). Of those, 181 were seen with both screen reads, whereas 141 were seen with 2D only compared with 73 were seen with integrated 2D and 3D mammography only (P < .0001).

Using positive integrated 2D and 3D screening as a condition to recall, the researchers estimate that the false-positive rate would have been 3.5% (95% CI, 3.1% - 4.0%) and could have potentially prevented 68 of the 395 false-positives (17.2%; 95% CI 13.6% - 21.3%) without any missed cancers, according to the researchers.

"It's important to begin collecting this data and this information, because we need to have this in order to intelligently incorporate new technology into our clinical algorithm," said Carol H. Lee, MD, an attending radiologist at Memorial Sloan-Kettering Cancer Center in New York City, in a telephone interview with Medscape Medical News. Dr. Lee was not involved in the study.

"There are still lots of questions about who might be best served by this...what is going to be its impact on breast cancer mortality?" Dr. Lee added.

Stefano Ciatto, PhD, from the UO Senologia Clinica e Screening Mammografico, Department of Diagnostics, Azienda Provinciale Servizi Sanitari, Trento, and the Centro di Prevenzione Senologica, Marzana, Verona, Italy, is listed as the primary author. Dr. Ciatto died in May 2012, and Dr. Houssami is described as representing the researchers in a news release. Dr. Houssami receives research support from a National Breast Cancer Foundation Practitioner Fellowship and has received travel support from Hologic to attend a collaborators' meeting. Most of the researchers received assistance from Hologic in the form of tomosynthesis technology and technical support for the duration of the study, as well as travel support to attend collaborators' meetings. One coauthor receives research support from Australia's National Health and Medical Research Council programme to the Screening & Test Evaluation Program. Dr. Lee has disclosed no relevant financial relationships.

Lancet. Published online April 25, 2013.