Results from a Swedish study involving more than 1 million women showed
that women aged 40 to 49 years who underwent mammography were less likely to
die of breast cancer compared with women who were not screened.
Håkan Jonsson, PhD, associate professor of cancer epidemiology at
Sweden’s Umeå University, revealed the results of the Swedish
Mammography Screening in Young Women Cohort Study in a press conference leading
up to the 2010 American Society of Clinical Oncology Breast Cancer Symposium.
Although physicians agree on the value of mammograms for women aged 50
years and older, the effect of screening in younger women is still open for
debate. The Swedish government in 1986 mandated screenings for women aged 50 to
69 years but left the decision to screen younger women up to individual
To test the effectiveness of mammography on breast cancer mortality in
younger women, Jonsson and colleagues analyzed disease-specific deaths in
counties where women aged 40 to 49 years were invited to screening and in
counties where those women were not invited to screening.
Researchers used 1970 to 1985, the period just before mammography became
mandatory in older women, as a reference. There were 4.8 million person-years
and 607 breast cancer deaths in the experimental group during the reference
period and 6.3 million person-years and 846 breast cancer deaths in the control
At an average follow-up of 16 years, Jonsson and colleagues found a 26%
decrease in mortality in counties where younger women were invited to screening
compared with the control group. Disease-specific mortality decreased 29% for
women who underwent screening.
“We saw a significant reduction from mammographic screening in
women aged 40 to 49,” Jonsson said. “The number of women between ages
40 and 49 needed to be invited to screening to save one life was an estimated
1,250.” — by Jason Harris
For more information:
- Jonsson H. Paper #67. Effectiveness of population-based service
screening with mammography for women age 40 to 49. Presented at the 2010 ASCO
Breast Cancer Symposium; Oct. 1-3, 2010; Alexandria, Va.
This study adds to our knowledge of mammography’s performance in
this age group. Many women age 40 to 49 want unambiguous recommendations
regarding whether to undergo mammography. While the optimal scheduling of
regular mammograms continues to be discussed, the critical message is that all
women, beginning at age 40, should speak with their doctors about mammography
to understand the potential benefits and risk of the test, and to determine
what is best for them as individuals.
— Jennifer C. Obel, MD
professor, Medical Oncology, NorthShore University HealthSystem