Janet D. Allan, Ph.D., R.N., C.S. is the Vice-Chair,
U.S. Preventive Services Task Force. She has been Dean and Professor,
School of Nursing, University of Texas Health Science Center at San Antonio
since 1997. She previously worked in various executive positions within
Family Nurse Practitioner Programs and has also been awarded a number
of training grants in primary care.
Mammography For Women 40 And Over
Women age 40 and over should get a mammogram every one to two years. That
recommendation comes from the US Preventive Services Task Force, an independent,
private-sector panel of experts in prevention and primary care that is sponsored
by the federal Agency for Healthcare Research and Quality (AHRQ).
But women have been hearing a lot of news reports about mammography lately,
and many seem to contradict each other. With all these different reports about
the value of mammography, what does this newest recommendation mean?
First, here are the facts:
- After lung cancer, breast cancer is the second leading cause of cancer-related
death, and the most common cancer among American women.
- Last year an estimated 192,200 women were diagnosed with breast cancer.
Twenty percent of those women died from it.
And most importantly,
- Early detection saves the lives of women at every age.
Let's identify women's risk factors, beginning in their 40s, and then discuss
the benefits of mammography as well as the potential risks. After that, we'll
examine some of the reasons for the confusion, and then discuss how women 40
and older can decide when to have a mammogram and how often.
Who is at Risk?
If you have a sister or mother (or other close relative) who has had breast
cancer or if a previous breast biopsy showed an irregular pattern of cell growth,
you are at increased risk compared to other women your age.
What is Mammography?
It is an X-ray of the breast to screen for abnormalities that may indicate
What are the Benefits?
Regular mammography can reduce your chance of dying from breast cancer. In
making its recommendation, the Task Force found fair evidence for women in their
40s that getting a mammogram every 1-2 years could reduce their chances of dying
from breast cancer by about 20 to 25 percent over a 10-year period. For older
women, the evidence is even stronger.
What are the Risks?
One way that a mammogram may cause harm is the psychological anxiety of a "false-positive,"
i.e., a screening mammogram that appears to show an abnormality. The vast majority
(80-90%) of abnormal mammograms turn out be false alarms in women who don't
have cancer. Many false-positives can be resolved with follow-up mammography,
but some will require breast biopsy (usually performed by sticking a needle
into the breast) to determine whether cancer is present. Some experts view
the over-diagnosis of ductal carcinoma in situ (DCIS) as a potential harm of
mammography. Additional problems include the costs and time that these extra
What About Clinical Examination or Self-Examination of the Breast?
The Task Force also noted that there is insufficient evidence to recommend
for or against routine clinical breast examination alone as a screening tool
for breast cancer and insufficient evidence to recommend for or against routine
teaching or performing routine breast self-examination. While these techniques
detect some additional cancers, there was not enough evidence to determine whether
they reduced deaths from breast cancer.
How Do I Decide?
Like other cancer screening tests, the majority of abnormal mammograms turn
out to be false-positives or normal exams. Because women under 50 have denser
breasts and because there are fewer incidences of breast cancer in women under
age 50, there's a greater likelihood of false-positives. On the other hand,
because some tumors tend to grow more quickly in women before menopause, it
is that much more important to catch a tumor early. As women get older, the
benefits of regular mammograms increase and the chance of false-positive tests
Deciding at what age the potential benefits of mammography justify the potential
harm generated by a false-positive is an individual choice -- one a woman should
make by talking with her clinician.
Why the Conflicting Reports About Mammography's Value?
The debate began last year when a Danish article looking at previous work on
mammography found certain limitations. It was this part of the Danish review
that immediately made headlines. What didn't get reported was what limitations
meant in "scientific language."
These researchers had found problems or flaws in the way the studies were conducted.
This led them to discount the results of 6 of the 8 major studies of mammography.
The USPSTF, in examining the review of the Danish scientists (as well as other
studies with similar issues) found many of the same limitations or flaws but
concluded that these limitations were unlikely to account for the observed benefits
(or lack of benefits) from screening mammography. Taken together, the Task
Force felt the studies provided consistent evidence that mammograms reduced
deaths from breast cancer.
In other words, the underlying message was the same: Early detection reduces
deaths from breast cancer.
What Should I Do?
Determine- discuss - decide.
Determine what your own personal values are about testing and the potential
Discuss the benefits and risks of mammography at your age, family history,
other risk factors and your personal preferences.
Decide when to have a first mammogram and then how often to have them
For a fact sheet and other information about this recommendation, go to www.ahrq.gov/clinic/3rduspstf/breastcancer/,
or contact the AHRQ Publications Clearinghouse at 1-800-358-9295, or email at
Created: 7/30/2002  - Janet D. Allan, Ph.D., R.N., C.S.