Good morning, Senator. I am Richard Klausner, Director of the
National Cancer Institute.
I am here to talk about mammography screening for women ages
40-49. I want to thank
you for your interest in this important issue. Two weeks ago, a
conference was held at the
NIH that brought together experts in all aspects of mammography
and an independent
consensus panel to address the often confusing and sometimes
contentious debate that
surrounds the question of the age at which a woman should begin
regular mammography.
On behalf of the NCI, I had asked ,or the conference In response
to reports of new data,
primarily from Sweden, that addresses the great gap in our
knowledge concerning, the
potential benefit of population screening of women age 40-49 and,
as hoped, the
conference successfully stimulated the presentation and
discussion of new and updated
data.
From a scientific point of view, the value of any screening test
used in a healthy population
depends on the incidence of the disease, the mortality associated
with that incidence as
well as on the performance characteristics, shortcomings, and
risks of the screening
procedure. A woman's risk of breast cancer does not suddenly
change at a particular age
but gradually and steadily rises. It is not surprising therefore
that the value of widespread
screening follows a similar pattern. There is general agreement
that the population of
women between the ages of 50-69 benefits from regular
mammography. While breast
cancer does occur in very young women, there is general agreement
that, because of its low
incidence in this population, screening for all women in their
20's or,.10's is not warranted.
So we are left with the issue of women age 40 to 49. As a woman
enters her forties, she is
beginning to move from a time when regular population screening
is not warranted to one
where it is proven to be beneficial. The question is where that
line is crossed. Is it age 40?
Age 42? Age 46? Or Age 50?
Rather than concluding that there is only one right answer to the
question, the Panel
concluded that each woman should make an informed decision in the
transition decade of
her forties that is the right answer for her. Despite some press
accounts, I stated at the end
of the conference that I agreed with this conclusion of the
Panel. My concern was with the
balance and tone of the discussion in the Panel's draft, report.
It is my opinion that the
draft report of the Panel overly minimizes the benefits and
overly emphasizes the risks for
this population. A balanced statement of the pros and cons of
screening is essential for a
woman to make an informed decision whether to initiate regular
mammography in her
forties.
Do we now have evidence that would support a woman's decision if
she decides to begin
screening mammography in her forties? The best data we have is
from 8 randomized
clinical trials involving about 180,000 women, including the 5
Swedish studies. Few trials
have enough instances of death from breast cancer to achieve
statistical significance, but
analyzed all together, by a procedure called meta-analysis, there
is about a 15 percent
reduction in mortality. The meta-analysis included eight
randomized clinical trials that
were conducted over the past 30 years from the United States,
Sweden, Canada and Great
Britain. I would be happy to discuss the interpretation of them
studies in the question
period. What does this mean to an individual woman? In general,
a woman in her forties
has a 1 in 66 chance of being diagnosed with breast cancer and
about I chance in 190 of
dying of breast cancer that develops in that decade. A 15
percent reduction would lower
these odds of dying to about 1 in 220.
What does this mean? This year, over 30,000 women in their
forties will be diagnosed
with breast cancer and a 15 percent reduction in mortality would
mean over 1600 lives
saved. This year, about 27,000 women in their fifties will be
diagnosed with breast cancer
and over 3300 lives would be predicted to be saved via
mammographic screening in that
age group.
Why would a woman choose not to have a mammogram? What are the
limitations, and
downsides of mammography? The first relates to false positives
and the medical
procedures involved in follow-up of the false positives. If
women were to receive yearly
mammograms for 10 years, it is estimated that as many as 30
percent of all women will
have an apparent abnormality detected. An estimated one-fourth
of these result in biopsies
and, for women in their 40's, only about one-fourth. of these
biopsies will prove to be
cancer. In other words, most abnormal mammograms do not signify
cancer. Beyond false
positives, mammography may miss up to 25 percent of breast cancer
in young women, a
percentage that falls to 10-15 percent in older women (i.e.,
women over age 50).
What about the risks of radiation? This is a theoretical
concern, but it is based largely on
exposure to very high doses of radiation and in much younger
women. While the risks of
radiation should net be completely dismissed, there is no direct
evidence that exposure of
women in their 40's to the levels of radiation used in
mammography causes breast cancer
or poses any other health risk.
Where then do we go from here?
The National Cancer Advisory Board will discuss the issue of
screening mammography of
women in their forties in order to provide guidance to the NCI
concerning how we move
forward with information, education and research. We must
provide information to every
woman and her physician or caregiver and to ensure that such
information is accurate,
current and user-friendly.
The NCI has long funded vigorous programs in digital mammography,
in image analysis,
and in non-ionizing approaches to cancer imaging such as
ultrasound, MRI, optic scanning,
microwaves and other technologies. Dr. Blumenthal will describe
some of these efforts in
her opening statement.
The NCI will continue its long-standing commitment to support
research in new
modalities, of imaging and molecular detection, and we must
strive to enhance the value
and reduce the limitations and problems of current mammography.
The NCI, CDC and
DoD are supporting the Breast Cancer Surveillance Consortium, a
national mammographic
screening, and outcome database which, by the year 2000, will
include over 1.8 million
screened women and provide valuable data to improve the practice,
interpretation, delivery
and follow-up of mammography in this country.
Mammography is not a cure for breast cancer. Better screening
methods will not ever
replace the need to find real preventions and curative therapies.
Mammography has an
important place in our current approach to breast cancer, but we
tend to overestimate its
benefits. We must remember that 70 percent of breast cancer
deaths in women over 50
will still occur even with regular mammography. We must be
relentless in our search for a
cure.
Women deserve to active and educated participants in their own
health care decisions, and
we cannot produce certainty where it doesn't yet exist.
Physicians and scientists must be
active partners with consumers to use both the best evidence and
the best judgment to help
each woman reach a decision that is right for her. Based on
current evidence, we must
inform women about the pros and cons for initiating screening in
their forties. We must be
wholeheartedly committed to helping each woman weigh these pros
and cons as a critical
part of her health care.
Thank you. I would be pleased to answer any questions.
