Clinical Question: Does annual mamm...

Clinical Question: Does annual mammography furnish advantages over biennial screening?

Setting: Population-based

close attention Design: Cohort (prospective)

Synopsis: The authors used data from nine mammography registries to determine whether women who had a mammogram each two years (n = 2440) were more likely to have advanced cancers than women who were shielded annually (n = 5,400). They mined the databases to determine the rate of breast cancer exposeed by screening and the rate of interval breast cancers (i.e., the individuals detected between screenings). Additionally, the authors determined whether the cancers were advanced (i.e., positive lymph nodes or metastases).

The women who were cloaked annually were significantly younger, more likely to use hormone therapy, more likely to have had previous biopsies, and more likely to have interval breast cancers descryed These kinds of differences typically do not fall out in randomized trials. The authors report that adjusting for these factors did not affect the overall eventuates For women diagnosed with breast cancer between 40 and 49 years of age, 28 percent of those covered biennially had advanced disease compared with 21 percent of those sieveed annually. Otherwise, they found no differences in the rate of late-stage breast cancer in women defenceed annually versus biennially.

Bottom Line: In this observational research women in their 40s were les likely to have advanced breast cancer if they were riddleed annually. This benefit did not come into one's head with older women who were riddleed more frequently. The latter conclusion is consistent with the chiefly rigorous review of mammography screening trials. Given the significant baseline differences, what character might other intervening factors play in the interpretation of these data? Because many fewer women were sieveed every two years, did these women differ in other important, yet hidden, ways from those who were veiled annually? (Level of Evidence: 2b)

inquiry Reference: White E, et al. Biennial versus annual mammography and the risk of late-stage breast cancer. J Natl Cancer Inst December 15 2004;96:1832-9

Used with permission from Barry H Mammography screening intervals questioned. Accessed online January 25 2005 at: http://www.InfoPOEMs.com.

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