Mammography reduces breast cancer mortality in women aged 40–49 years
MedWire News: Annual mammography screening of women in their forties leads to a reduction in breast cancer mortality, show the results of the largest study to date among women in this age group.
In 1986, the Swedish National Board of Health and Welfare issued guidelines recommending that county councils invite women for mammography screening from the age of 40 years, explain Barbro Numan Hellquist (Umeå University, Sweden) and colleagues in the journal Cancer.
However, councils with a lack of resources were recommended to focus on women aged 50 years and older, say the researchers. As a result, approximately 50% of the Swedish counties invited women for screening from age 40 years, and the remaining counties invited women aged 50 years and older.
This unique situation has allowed Hellquist and team to study the effectiveness of mammography screening in more than 600,000 women younger than 50 years of age.
The researchers compared breast cancer mortality among women who were invited to screening at age 40 to 49 years between 1986 and 2005 (study group) with women in the same age group during the same period who were not invited to screening (control group).
After a mean follow-up of 16 years, there were 803 breast cancer deaths and 1238 breast cancer deaths in the control group.
The researchers calculated that breast cancer mortality was a significant 26% lower among women who were invited to screening compared with those who were not. Furthermore, invitees who actually attended mammography screening had a 29% lower breast cancer mortality rate than those who were not invited to screening.
They found that 1252 women would need to be screened during a 10-year period (corresponding to approximately six mammography episodes) to save one life.
"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," said Carol Lee, Chair of the American College of Radiology Breast Imaging Commission.
"There is no excuse not to recommend that average-risk women begin annual screening mammography at age 40."
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By Laura Dean