October 5, 2010 — A landmark breast cancer screening study of women 40-49 years of age, published online in Cancer, has proven that annual mammography screening of women in their 40s reduces the breast cancer death rate in these women by nearly 30 percent. The results of the largest study ever conducted on women in this age group confirm that the use of the age of 50 as a threshold for breast cancer screening is scientifically unfounded. Women should begin getting annual mammograms at age 40.
“This study, which looked at the performance of screening mammography as it is actually used, rather than relying on mathematical modeling, shows without a doubt that mammography decreases deaths from breast cancer in women aged 40-49 by nearly one third. There is no excuse not to recommend that average risk women begin annual screening mammography at age 40,” said Carol H. Lee, M.D., chair of the American College of Radiology breast imaging commission.
In November of 2009, the United States Preventive Services Task Force (USPSTF) ignored published data showing a similar death rate reduction to this landmark trial and withdrew support for screening women 40-49. This study is more robust and based on real-world numbers, and proves that the benefit is nearly twice that of the USPSTF estimate of 15 percent.
The Swedish trial followed more than 600,000 women for 16 years. The number of breast cancer deaths among the women in the study who did not receive mammograms was twice as high as those who underwent screening.
For more information: http://onlinelibrary.wiley.com/doi/10.1002/cncr.25650/abstract
April 15, 2026 
