Digital mammos better than film for younger women

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Women with dense breasts, who are pre- or perimenopausal, or who are younger than age 50 may benefit from digital mammograms, according to results from a recent trial published in the February 2008 issue of Radiology.

Etta Pisano, MD, professor of radiology and biomedical engineering, chief of breast imaging at the University of North Carolina School of Medicine in Chapel Hill, and co-author of the study, said that a digital mammogram will produce more accurate findings than a film mammogram.

The study sought to retrospectively compare the accuracy of digital versus film mammography in population subgroups of the Digital Mammographic Imaging Screening Trial (DMIST), defined by combinations of age, menopausal status, and breast density, by using either biopsy results or follow-up information as the reference standard, Pisano said. DMIST included women who underwent both digital and film screening mammography.

Areas under the receiver operating characteristic curve (AUCs) for each modality were compared within each subgroup evaluated (age < 50 vs. 50–64 vs. ≥65 years), dense vs. nondense breasts at mammography, and pre- or perimenopausal vs. postmenopausal status for the two younger age cohorts [10 new subgroups in total]) while controlling for multiple comparisons (P < .002 indicated a significant difference).

All DMIST cancers were evaluated with respect to mammographic detection method, mammographic lesion type, digital machine type, mammographic and pathologic size and diagnosis, existence of prior mammographic study at time of interpretation, months since prior mammographic study and compressed breast thickness. Of the 49,528 women enrolled, breast cancer status was determined for 42,760 women, who were chosen for the study.

According to the results, pre- or perimenopausal women younger than 50 years who had dense breasts at film mammography comprised the only subgroup for which digital mammography was significantly better than film (AUCs, 0.79 vs. 0.54). Breast Imaging Reporting and Data System–based sensitivity in this subgroup was 0.59 for digital and 0.27 for film mammography. AUCs were not significantly different in any of the other subgroups. For women aged 65 years or older with fatty breasts, the AUC showed a nonsignificant tendency toward film being better than digital mammography (AUCs, 0.88 vs. 0.70).

Pisano and colleagues concluded from the study that “digital mammography performed significantly better than film for pre- and perimenopausal women younger than 50 years with dense breasts, but film tended non-significantly to perform better for women aged 65 years or older with fatty breasts.”