Study shows mammography not tied to ca mortality decrease. (At Odds with Federal Recommendation).

Intensive breast cancer screening, including mammography and instructions on self-examination, did not reduce breast cancer-related mortality in women aged 40-49 in up to 16 years of follow-up, the most recent results of the Canadian National Breast Screening Study-1 show.

These latest findings are similar to those reported at 7- and 10-year follow-up from the same randomized, controlled trial, but are at odds with those from other studies on which the U.S. Preventive Services Task Force based its own screening recommendations earlier this year.

In February, the task force recommended screening mammography every 1-2 years in women aged 40-49, as well as in older women. The decision to recommend screening in the 40-49 age group was based on what the task force considered "fair" evidence from a metaanalysis of eight randomized, controlled studies. That analysis suggested that screening mammography beginning at age 40 significantly reduces breast cancer mortality among women.

For the Canadian study, 50,430 volunteers aged 40-49 with no previous breast cancer diagnosis and no mammography screening in the previous 12 months underwent physical breast examination and received instruction on proper self-examination. They were then randomized to receive, for 45 years, either annual mammography and physical breast examination along with instructions to perform routine breast self-examination or the usual community care, including annual follow-up.

At 11-16 years of follow-up (mean of 13 years), 105 breast cancer deaths had occurred in the mammography group, and 108 occurred in the usual care group. Invasive breast cancer occurred in 592 women in the mammography group and 552 women in the usual care group. These differences were not statistically significant, Dr. Anthony B. Miller of the University of Toronto and his colleagues reported (Ann. Intern. Med. 137[5, part ...