can detect some breast cancers when they are
small, before they have spread and become
incurable. Treatment for breast cancer is more
effective if breast cancer is found when it is
small and localized. There are differences in the
benefits of mammograms according to age.
50 to 69 years old: There is good evidence
that mammograms decrease deaths from breast
cancer in women aged 50 to 69 years if breast
cancer is adequately treated after discovery by a
mammogram. Studies found fewer breast cancer
deaths in women aged 50 to 69 years who received
routine mammograms compared to women who did not
receive routine mammograms.
10,000 women 50 years old, 260 will die of breast
cancer in the next 20 years. If all 10,000 women
get routine mammograms over the next 20 years, 37
breast cancer deaths may be prevented. This means
for women aged 50 and older, mammograms prevent
one breast cancer death for every 270 women
screened regularly for 20 years.
Women 40 to 49:
There is some evidence that mammograms may decrease
deaths from breast cancer in women in their forties. In
studies involving thousands of women, there were fewer
deaths from breast cancer in those who got routine
mammograms than in those who did not, but this benefit
only appeared ten years after screening began.
Among 10,000 women 40
years old, 37 will die of breast cancer in the next 10
years. If all 10,000 women get routine mammograms over
the next 10 years, 4 breast cancer deaths may be
prevented. This means for women in their forties,
mammograms prevent one breast cancer death for every
2,500 women screened regularly for 10 years.
Salzmann P, Kerlikowske K, Phillips K. Cost-effectiveness
of extending screening mammography guidelines to include
women 40-49 years old. Ann Intern Med 1997;127:955-65.
Berry, D.A. Benefits and risks of
screening mammography for women in their forties: a statistical appraisal. J
Natl Cancer Inst 1998;90:1431-1439.