This article appeared in the New Zealand Herald in 2005.
Breast cancer awareness month ended yesterday. The Sky Tower was
bathed in pink throughout October. Radio and newspapers exhorted
women to have mammograms. There were gala evenings to raise funds
for research and free public seminars.
Breast cancer has indeed achieved celebrity status. Faced with the
barrage of publicity it is not surprising that most women
overestimate their personal risk of getting breast cancer.
Fortunately 90 per cent will never get it and only a third of those
diagnosed will die from it. We are told that over 2000 new cases
are diagnosed annually and 622 women die each year. This is indeed
a concern but unpublicised is the fact that 546 women die from lung
cancer and a further 563 from bowel cancer annually. Cancer kills
7620 New Zealanders each year, of whom 622 have breast cancer.
These statistics are only a small part of our overall health
catastrophe. Ischaemic heart disease, smoking-related illness,
diabetes, obesity and other preventable diseases are wreaking
havoc.
Few women are aware they have a far greater chance of dying from
heart disease (2704 deaths) or a stroke (1620 deaths) than breast
cancer. Overzealous campaigning for breast cancer awareness skews
funding and prevention initiatives.
Women are advised that there is little that they can do to prevent
breast cancer and that early detection with screening mammograms is
their best protection.
A widely shown ad informs women that "a mammogram is the best way
to make sure you stay well and healthy for your whanau."
If we step back for a moment it becomes apparent that there is much
more that can be done to stay well and healthy than simply having a
mammogram. Some of these measures may also specifically reduce the
risk of breast cancer.
More young women are smoking at a time when the overall incidence
of smoking is declining. While the cause of breast cancer remains
unclear, smoking is clearly implicated in lung cancer.
The smoke-free workplace legislation acknowledges the harmful
effects of cigarettes. Why stop here? Why not a month-long campaign
highlighting lung cancer? The Government could ban the import of
cigarettes if it chose. It seems hard to justify spending $40
million a year on mammographic screening while not taking such a
measure to deal with an equally deadly killer.
Many researchers suspect a link between pesticides, herbicides and
cancer. This has been difficult to prove and is consequently
dismissed by many as irrelevant. It makes sense, however, to treat
chemicals carefully. We need to invest more in evaluating the
safety of chemical products, plastics and electromagnetic radiation
in industry, agriculture and the home.
Moderate to heavy alcohol intake has been linked to a number of
cancers as well as breast cancer. Reducing alcohol intake would be
a sensible precaution.
Diet is one of the most important lifestyle factors and has been
estimated to account for up to 80 per cent of cancers of the colon,
breast and prostate. More women (4324 a year) die from ischaemic
heart disease and strokes than from cancer.
We know that smoking, obesity and inactivity play a major role in
these conditions. If women are concerned enough about their health
to endure the discomfort and anxiety associated with mammograms
then, rationally, that effort should include initiatives to lose
weight, stop smoking, exercise regularly and eat healthily. There
is encouraging evidence that weight loss and reduced alcohol
consumption may specifically reduce breast cancer risk.
It is misleading to let a woman who is overweight and a heavy
smoker believe that simply having a mammogram is the most important
step she can take to stay well.
Women overestimate what mammograms can achieve and are not aware of
the limitations and associated risks. These unrealistic
expectations can result in a sense of betrayal when breast cancer
develops despite regular mammograms, sometimes over many years.
While many medical investigations require some type of informed
consent, women attending for screening mammograms are seldom
provided with objective information on the risks and benefits.
Diagnostic tests are used to assess a problem such as a lump that
has been found and, in this setting, a mammogram may be very
helpful. Screening mammography, by contrast, involves x-raying an
entire healthy population with no symptoms with the aim of
detecting cancers before they are big enough to feel.
If you are one of the 10 per cent of women destined to get breast
cancer then a screening mammogram may detect it at an early stage
where optimal treatment may reduce your risk of dying. That makes
you a winner. If, however, you are one of the 90 per cent who is
never going to get breast cancer, then screening will involve
unnecessary x-rays for more than 25 years of your life.
Along the way there is a reasonable chance that you will end up
having extra tests to investigate changes that are not cancerous
and this may even involve surgery.
Unfortunately we have no crystal ball to tell which group you
belong to as the majority of women with breast cancer have no
identifiable risk factors.
The benefit of screening mammography comes from improved survival
associated with early treatment. Advocates claim a 45 per cent
reduction in the risk of dying from breast cancer in the screened
population aged 65 to 69, a 30 per cent reduction for women aged 50
to 65 and a 20 per cent reduction for women 45 to 49.
If this is correct, an average 30 per cent reduction in mortality
means that more than 400 out of the 600 deaths recorded annually
will still occur despite optimal screening.
Most information on screening states categorically that trials have
proved that it saves lives. Many would be surprised to learn that
there is some controversy regarding the validity of these
results.
New Zealand has never conducted a trial to test the efficacy of
screening in our environment and we base our decisions on overseas
results. The original trials were conducted more than 20 years ago
and were poorly designed by modern standards. They have been
subject to various reviews and, while enthusiasts claim conclusive
evidence of benefit, one should be aware that the experts do not
agree on how many lives may be saved.
It is important to realise that mammograms do not detect all
cancers. Some 10 to 15 per cent of breast cancers will not show up
on a mammogram and in women 40 to 50 years of age with dense breast
tissue, this miss rate may be as high as 25 per cent. These are
called false negative results.
Some cancers will develop in the time between screening mammograms.
Some women are lulled into a false sense of security precisely
because they may have had a normal mammogram in the last few
months.
The use of young celebrities to promote breast cancer awareness
campaigns can create the misleading impression that women in their
20s and 30s should be having screening mammograms. While there is
heated debate about the benefits for women aged between 40 and 49,
not even the most avid enthusiasts recommend routine screening in
average-risk women younger than 40. As a breast surgeon I witness
the tragic consequences of breast cancer on a daily basis. No
effort should be spared to reduce the impact of this disease. But
women are entitled to balanced information before proceeding with
screening mammography. It is patronising to assume that this might
be seen to cause confusion and discourage participation.
The fight against breast cancer cannot be won in isolation, nor by
simply extending mammographic screening. If we are to rise to the
challenge presented by current disease statistics, then we need to
direct our energies and resources to risk reduction and primary
prevention of all degenerative and malignant disease.
These initiatives will almost certainly require a radical and
unpopular shift in how we manage industry, our environment and
personal lifestyles.
There is much that can be done and no better time to start than the
present.
* Trevor Smith is a breast surgeon at the Ascot Hospital in
Auckland