Myths, Hopes, and Facts About Breast Cancer
For: The Gold Standard, March 2002
Breast cancer is the disease that women fear most,
according to many surveys—and the subject of scores of magazine
articles, TV shows, websites, and books. Women trying to keep up
have to weed through a pile of information, misleading and confusing
statements, and deliberate misinformation (such as the Internet
rumors that antiperspirants and underwire bras cause breast cancer:
they don't). Here's what people are saying, and asking.
Stress and breast cancer: cause and effect?
There's no evidence that emotional upset or severe
stress (temporary or chronic) causes breast cancer, or causes it
to recur after treatment. Or indeed that personality or attitude
has any relation to breast cancer. This is a myth—and a heavily
promoted myth. True or not, a recent study in Psycho-Oncology
reports that a high percentage (42%) of women who had survived breast
cancer by at least two years believed stress was to blame for the
cancer. About 26% blamed genetics (a better guess), and 25% the
environment (surprisingly little is known about this).
The researchers concluded that doctors should ask
their patients what they think about the causes of breast cancer.
It might be comforting for a woman to learn that her emotions did
not "give" her breast cancer.
Women whose cancer had not recurred were asked what
they thought had kept them healthy. An even higher proportion (60%)
attributed their survival to a positive attitude. They cited good
diets, exercise, stress reduction, luck, and taking tamoxifen, among
other things. Indeed, doctors do think that what's called a "fighting
spirit" can boost a woman's chances of survival.
In other words, you don't give yourself breast cancer.
But a positive attitude, including a willingness to comply with
treatment, may indeed help you get well.
Mammograms: outmoded?
In spite of what you may have read, mammography is
still the gold standard for detecting breast cancer, and it's likely
to remain the gold standard for some time. This comes from a new
detailed report from the Institute of Medicine, part of the National
Academy of Sciences. A committee appointed by the Institute and
headed by Dr. Joyce Lashof (Associate Chair of our Editorial Board)
reviewed the evidence and found that mammograms have reduced the
mortality rate from breast cancer by one third in women aged 55
to 70.
And a subsequent study in the journal Cancer
claimed even greater benefits. In Sweden, where 85% of women age
40 to 69 get the test, the death rate from breast cancer among women
having mammograms was two-thirds less than that of women who didn't
get screened. This was not a controlled study, and may have over-estimated
the benefit. Still, it adds support for mammograms. While they don't
prevent breast cancer, they can detect it at early, treatable stages,
which is why the mortality rate has dropped.
Our recommendations still hold: all women should begin
having annual mammograms at age 50. Women at higher risk for breast
cancer, in consultation with their physicians, may need to start
mammography at 40 (see WELLNESS LETTER, August 2000).
New screening tests are also coming into use. Here
are three that may one day be widely used in addition to conventional
mammography:
Full-field digital mammography:
a very similar process for the woman, but it uses electronic detectors
and produces digital images that can be easily stored. So far it
doesn't look any more accurate than regular mammograms, and it's
more costly. But it may prove to be a better tool for women with
dense breasts.
Magnetic resonance imaging
(MRI): widely used already, but not to detect breast cancer.
MRI, which uses a magnetic field to create an image, may be useful
for detecting less common forms of breast cancer, and for women
with dense breasts. As the technology improves, its usefulness for
detecting breast cancer may also improve.
Ductal lavage: a very
thin catheter is inserted into the milk ducts, where most cancers
originate, and cells are extracted. It's FDA-approved as an adjunct
to mammography and already in use for high-risk women. It might
one day be useful for detecting precancerous cells and thus allow
for preventive treatment—in much the same way that a Pap test
can detect potential cancers of the cervix. But ductal lavage has
drawbacks—in particular, too many false positives—and
is not ready for wide use.
Other methods are already in use: ultrasound is a
useful adjunct to mammography (see WELLNESS LETTER, July 1999);
and genetic testing can help some high-risk women make treatment
decisions. Some new scanning techniques are still in the developmental
stage. And new biological knowledge (that is, understanding of the
nature of tumors and potential markers that may reveal the presence
of tumors) will help in diagnosis as well as treatment.
While mammography is not perfect, it is still the
best of the tests. And don't forget regular breast exams by a professional,
as well as the monthly breast exams you do yourself.
Older women: not at risk?
The idea that breast cancer is a young woman's disease
is untrue, and may have arisen from many articles in women's magazines
about young women with breast cancer. In fact, breast cancer risk
rises dramatically with age. A recent study of Canadian women aged
50 to 75 found, however, that women aged 70 to 75 were less likely
to get mammograms. The reasons for this were complex: fear of the
test and of results played a role, but so did the mistaken idea
that older women are less susceptible to breast cancer. Fatalism
stopped some women: "If I get it, I get it—no point worrying."
This is not a constructive way to think about your health.
Women who get regular blood pressure checks, exercise,
and don't smoke are more likely to get mammograms, whatever their
age, according to research. It makes sense
to take good care of yourself in all the ways you can—which
includes getting regular mammograms—into your seventies and
eighties and beyond.
Breast cancer prevention: exercise and diet?
If you're keen on taking care of yourself, you want
to know how to prevent breast cancer. Will a good diet help? Exercise?
Avoiding alcohol? Unfortunately, it's been hard to pinpoint any
way to prevent breast cancer.
High-fat diets were long suspected of raising breast
cancer risk, and this link has been much studied. But there seems
to be no connection, although a diet high in animal fats is harmful
in other ways. Surely, scientists thought, eating lots of fruits
and vegetables protects against breast cancer. But while such a
diet is a very good idea, there's no certainty it protects against
breast cancer.
As for exercise, there is some indication that getting
regular exercise over a lifetime
is protective—but the evidence is not strong. Perhaps exercise
is beneficial because it helps control weight (obesity increases
the risk of breast cancer). Like eating fruits and vegetables, getting
regular exercise is an excellent idea for other reasons, whatever
its effect on breast cancer risk.
Some studies have found that alcohol increases the
risk of breast cancer—but others have found no increased risk
except in heavy drinkers. It's far from certain. Moderate drinking—one
drink a day for women—does lower the risk of heart disease
(see WELLNESS LETTER, August 1997).
Remember this: The causes of breast cancer remain essentially unknown. Genetics and estrogen levels over a lifetime no doubt play the major roles.
UC Berkeley Wellness Letter, July 2001
