Screening Mammograms in Older Women: Annual or Biennial?

Controversy continues to surround recommendations about screening mammography intervals. Investigators prospectively collected data from 1999 through 2006 on women aged 66 to 89 at baseline who received screening mammograms in five U.S. regions in which mammography records could be linked with Medicare claims data.

Of 140,000 women, invasive breast cancer or ductal carcinoma in situ (either screen-detected or interval-detected) was diagnosed in nearly 3000. The percentage of invasive tumors with adverse characteristics (stage IIb or higher, size >20 mm, or positive lymph nodes) was similar among women receiving annual and biennial screens and did not vary significantly with respect to comorbidity scores. The 10-year cumulative likelihood of …