The present findings, which appear in the December 9th issue of the Lancet, are consistent with what has been seen in other studies.

The study involved 160,921 young women who were randomized to undergo annual mammographic screening starting at age 40 or 50. The trial was conducted at 23 National Health Service breast-screening units in England, Wales, and Scotland.

After a mean follow-up of 10.7 years, mammographic screening starting at age 40 rather than 50 was associated with a 17% reduction in breast cancer mortality, but this did not reach statistical significance, lead author Dr. Sue M. Moss, from the Institute of Cancer Research in Sutton, U.K., and colleagues note.

After adjusting for nonattendance at the first mammographic screening session, earlier screening appeared to cut breast cancer mortality by 24% but this too was not statistically significant.

"Future follow-up of this trial will provide more information about the full effect of screening in this age-group," Dr. Moss' team concludes. "There is a need for research to identify more accurately, perhaps by modelling, the benefit of commencing screening at different ages below 50 years."

In a related commentary, Dr. Benjamin Djulbegovic, from the University of South Florida in Tampa, and Dr. Gary H. Lyman, from the University of Rochester Medical Center in New York, comment that "although the best estimates of harms from screening mammography seem to be less than the benefits, they remain too uncertain to conclude with a high level of confidence that screening mammography (in young women) is associated with a net benefit."

Last Updated: 2006-12-07 18:30:14 -0400 (Reuters Health)

Lancet 2006;368:2035-2037,2053-2060.

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