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Mammograms: To screen
or not to screen?
The mammography debate rages on, newly fueled by results from a Canadian
trial published in the Sept. 3, 2002, Annals of Internal Medicine.
The Canadian National Breast Screening Study (CNBSS) is the first trial
designed specifically to assess screening mammography in women ages 40–49.
In the early 1980s, the CNBSS recruited 50,430 women in this age group
with no history of breast cancer. Half were assigned to receive annual
mammograms; the other half, to receive “usual care,” meaning
that mammograms were done only if a patient’s doctor recommended
After an average of 13 years, there were 105 breast cancer deaths in
the mammography group and 108 in the usual care group — not statistically
significant difference. The researchers concluded that mammograms are
not justified for breast cancer screening in women under age 50.
Critics of the CNBSS trial said the data came from older technology,
before improved imaging was available. The women who took part enrolled
20 years ago, when mammography images were less clear and radiologists
weren’t as proficient at reading them.
But the American Cancer Society, the Centers for Disease Control and
Prevention, and the National Cancer Institute advise women to get annual
mammograms starting at age 40.
To further muddy the waters, the same issue of Annals of Internal
Medicine that carried the CNBSS results published new guidelines
for breast cancer screening from the U.S. Preventive Services Task
Force (USPSTF). The USPSTF is a panel of health experts that analyzes
published research and makes suggestions about preventive health care.
The group recommends having a mammogram every one to two years, starting
at age 40. The authors assert that there is no convincing evidence to
support the theory that starting annual screening at age 40 exposes women
to undue harm, with minimal chances of finding cancer.
On the other hand, if mammograms can find breast cancer, why not start
at age 40? For one, the screening test may adversely affect some women.
False-positive results (which flag a problem when none exists) can lead
to anxiety and further testing.
In defense of its recommendations, however, the USPSTF says that anxiety
usually disintegrates after cancer is ruled out. And even when it doesn’t
go away, anxiety doesn’t seem to discourage women from continuing
their screening regimen.
If you have a family history of breast cancer or other risk factors,
it makes sense to start mammograms at age 40 (perhaps earlier, depending
upon your level of risk). For everyone else, a discussion with your doctor
is the most sensible first step. If she or he feels annual mammograms
are unnecessary for you, and you’re comfortable with the decision,
waiting until you’re 50 should be fine.
November 2002 Update
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New Cancer Prevention Guidelines
While some risk factors for developing cancer, such as family history,
can not be changed, there are ways for people to reduce their chances.
The American Cancer Society (ACS) recently released new dietary and physical
activity guidelines for cancer prevention.
One of the most basic tenets of a healthy diet is eating plenty of fruits
and vegetables. The ACS recommends eating no less than 5 servings of
a variety of fruits and vegetables every day. Many people have heard
of antioxidants but aren't sure exactly what they are or what they do.
Antioxidant nutrients (such as vitamin C, vitamin E, and carotenoids)
protect the body against the tissue damage that occurs as a result of
normal metabolism. Because such damage is associated with increased cancer
risk, the antioxidant nutrients are thought to protect against cancer.
Studies suggest that people who eat more vegetables and fruits, which
are rich sources of these antioxidants, have a lower risk for some types
of cancer, but studies of antioxidant supplements have not yet shown
a reduction in cancer risk.
Choosing whole grains over processed (refined) grains and sugars will
also help, so stick to whole grain rice, bread, pasta, and cereals. Also,
limit your red meat intake. When you do eat it, choose the way you cook
it carefully. While adequate cooking is necessary to kill harmful microorganisms
in meat, some research suggests that frying, broiling, or grilling it
at very high temperatures creates chemicals that might increase cancer
risk. Braising, steaming, and poaching meats cuts down on the production
of these chemicals.
Drinking too much alcohol is an established cause of cancers of the
mouth, throat, liver, and breast. Therefore, the ACS recommends limiting
alcoholic consumption to 2 drinks per day for men and 1 drink per day
The ACS also reminds people to remember that "low fat" or "fat
free" snacks like cakes and cookies are often high in calories.
High sugar intake can lead to obesity and elevated insulin levels, conditions
that increase cancer risk.
Physical activity is also an important component in the prevention of
cancer. Adults should engage in moderate-to-vigorous activity (walking,
leisurely bicycling, running, swimming) for 30 minutes or more at least
5 days a week.
Simple additions to your daily routine such as taking the stairs instead
of the elevator, taking 10-minute exercise breaks at work, and walking
to visit co-workers instead of emailing them are simple ways to increase
your activity level.
An unhealthy diet and lack of exercise can lead to weight gain and obesity,
conditions that are associated with developing cancers of the breast,
colon, endometrium, esophagus, gallbladder, pancreas, and kidney.
In addition to the general guidelines set forth by the ACS, there are
also answers to frequently asked questions about the rumored or theoretical
relationships between cancer and such substances as aspartame, beta-carotene,
calcium, coffee, fish oils, fluorides, folic acid, saccharin, and tea.
The ACS suggests that public, private, and community organizations create
environments that support the adoption and maintenance of these healthful
eating and physical activity behaviors. People should have access to
healthful foods in schools, at work sites, and when on daily outings
in their town or city.
For a copy of the complete set of guidelines, call the American Cancer
Society at 1-800-ACS-2345.
April 2002 Update
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Surgery for GERD
In recent years, people suffering from severe, chronic
heartburn that cant be controlled with medications have turned
to surgery with hopes for permanent relief and the prevention of esophageal
cancer. But the results of a recent study that assessed the well being
of patients a decade after they had surgery question its benefits.
Heartburn, also known as gastroesophageal reflux disease (GERD), occurs
when the opening between the esophagus and stomach relaxes spontaneously,
allowing acidic gastric juices to flow into the esophagus and cause irritation.
Medications for GERD include antacids, proton pump inhibitors that decrease
the amount of acid produced, and drugs that increase the tightness of
the esophageal. Surgery, an option usually reserved for hard-to-treat
GERD, involves folding the top of the stomach around the end of the esophagus
to create a tighter opening. This procedure has become more popular with
the development of minimally invasive techniques.
A study from the late 1980s of 247 heartburn patients found surgery was
better than medication at controlling symptoms. However, ten years later
a follow-up study of 239 of the original patients found many of the patients
who underwent surgery still suffered from heartburn. Though their symptoms
were less intense than those who received medication in the original
study, 62% of the surgical patients still took antireflux medication
regularly (compared to 92% of the medical patients).
The study also found that surgery failed to significantly decrease the
risk for esophageal cancer compared to treatment with medication. Chronic
heartburn is a risk factor for this cancer. However, the small size of
the study combined with the low incidence of esophageal cancer did not
rule out the possibility of a difference. A more surprising result of
the study showed surgical patients were more likely to die than patients
on medication. These deaths were not related to the surgery, but close
to half (48%) were related to heart disease. The researchers were unprepared
for this result and therefore have no data to explain this finding.
The results of this study suggest that while surgery may do a better
job at controlling the symptoms of heartburn, it doesnt eliminate
the need for medication or decrease cancer risk. In general, surgery
should be seen as an option of last resort for those patients whose symptoms
are hard to treat with medication.
June 2001 Update
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Walking for Women: A Great Step Toward Fitness
Ask any doctor for his or her advice for healthy living and you'll find
exercise a part of the prescription. However, it is one that patients
must "fill" themselves and that can be tough. The most recent guidelines
from the Centers for Disease Control and Prevention, the American College
of Sports Medicine, and the Surgeon General's report recommend that individuals
get at least 30 minutes of moderate-intensity activity on most (ideally
all) days of the week. Yet 60% of Americans don't regularly engage in
physical exercise at all.
Harvard Medical School researchers recently compared the effects of brisk
walking with more vigorous forms of exercise, specifically in women.
For this report, study investigators followed 72,488 women participating
in the Nurses' Health Study for 11 years. At the start of the study in
1986, these women were all between the ages of 40 and 65 and had no known
heart disease or cancer. They completed regular, detailed questionnaires
about their physical activity.
Researchers found that vigorous exercise and brisk walking reduces the
risk of heart attack for women by roughly the same amount. The bottom
line is that brisk walking for three or more hours per week can reduce
a woman's risk of cardiovascular disease by 30%-40%. Women who walk for
a longer time or combine walking with other vigorous physical activity
can expect to reduce their risk of heart disease even more. So women
don't have to sign up for aerobics or train for a marathon to substantially
reduce their heart disease risk. A good start is putting one foot in
front of the other at a good pace. For more information on exercise and
fitness, see page 51 of the Family Health Guide.
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Vitamin C: How Much Is Enough?
Vitamin C is touted as a potential weapon in combating
a range of illnesses, from the common cold to cancer and heart disease.
No one believes that taking vitamin C supplements in moderate doses presents
any danger, and foods rich in vitamin C (fruits and vegetables) offer
real health benefits. But could consuming large amounts of vitamin C
supplements be too much of a good thing?
Despite some theoretical dangers, vitamin C appears to have very few
toxic effects. However, at very high doses, vitamin C can indeed cause
problems. Diarrhea and abdominal bloating can result from taking several
grams at once a tactic that has been advocated by some for preventing
and treating the common cold.
Studies show that high doses of vitamin C could lead to over-absorption
of iron, which could potentially damage the heart, liver, and other organs.
Too much vitamin C may also contribute to kidney stones or give false-positive
readings on blood-stool tests. Such events occur rarely if ever, so these
really are minor concerns. But, even if people are not endangering themselves
much by taking large amounts of vitamin C, research suggests that they
are not helping themselves either. Studies of dietary patterns show that
people who get an average of 200 mg of vitamin C per day from fruits
and vegetables have a lower risk of cancer especially cancers
of the mouth, esophagus, stomach, colon, and lung. Five servings of fruits
and vegetables a day are enough to provide this much vitamin C. In research
trials, consuming more vitamin C has not led to a detectable increase
in health benefits. As for heart disease, there is evidence that marked
vitamin C deficiency is associated with an increased risk of cardiovascular
problems, but there is no proof that taking supplements offers additional
benefits over those offered by a diet that includes the recommended amounts
of fruits and vegetables.
Experts from the National Institutes of Health recently reviewed the
evidence on this topic and concluded that, ideally, people should try
to get their vitamin C from eating five servings of fruits and vegetables
daily. Taking more than one gram (1,000 milligrams) of vitamin C per
day should be discouraged because of the small, yet real, possibility
of adverse effects. These recommendations do not mean that people who
are taking vitamin C supplements or a multivitamin pill should stop,
particularly if they just can't manage to eat enough fruits and vegetables.
However, there is no reason to take high doses of vitamin C, and there
may even be a small possibility of harm. For more information on vitamins
and minerals, see page 43 of the Family Health Guide.
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