- Without question, a brain tumor is one
of the most frightening diagnoses you can face. Not only must you confront
mortality, but also the knowledge that the slide toward death may be accompanied
by something equally terrifying: the loss of self as cancer takes over
the organ responsible above all for who you are.
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- Each year, the number of people who face
such a diagnosis is increasing. Since the early 1970s, the incidence of
cancerous tumors that start in the brain has steadily crept upward -- increasing
by more than 1 percent a year, according to a National Cancer Institute
(NCI) registry.
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- The increase has been far more dramatic
in adults age 65 older. Since 1980, incidence rates for malignant tumors
beginning in the brain have increased by 2.5 percent a year, according
to the NCI registry. The increases become even more apparent among older
people. Since 1973, malignant brain tumors increased more than 200 percent
for those 75 to 79; 300 percent in the 80-to 84-year-old group, and more
than 500 percent for those 85 and older.
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- Even to an untrained eye, the statistics
are astounding. To doctors, the numbers and possible explanations for them
are the subject of controversy. Not even the question of whether brain
tumors really are occurring more frequently has been settled. Many attribute
the increases to better diagnostic technology and an aging population.
Others, however, are exploring the possibility of whether there's something
in the environment playing a role.
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- "The final chapter is not yet written,"
said Dr. Ed Creagan, a Mayo Clinic oncologist. "Ongoing studies are
clearly necessary to help clarify this important question."
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- Outlook grim
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- Physicians refer to cancerous tumors
that originate in the brain as "primary" tumors. The word "primary"
is used to distinguish these tumors from cancers that start elsewhere and
spread to the brain.
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- Although primary malignant brain tumors
account for less than 2 percent of new cancer cases, according to the American
Cancer Society (ACS), they include some of the deadliest types of cancer.
One common type, glioblastoma multiforme, can double its size every 10
to 11 days.
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- The cancer-fighting arsenal of surgery,
radiation and chemotherapy has had limited success against primary malignant
tumors, according to the ACS. Although treatments have improved, survival
rates remain grim.
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- That's one reason, experts say, that
dozens of studies have looked more closely at why the numbers are rising.
Potential suspects that have been all but ruled out include cellular phones,
electromagnetic fields and the sweetener aspartame (Nutrasweet).
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- "There's a lot of interest in this,"
said Dr. Philip Lowry, a Mayo Clinic physician who recently published a
study of brain tumors in elderly patients at four Twin Cities hospitals.
"I think one reason is that the outcomes are generally still so poor
in the face of what appear to be rapidly increasing rates."
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- Artifact of technology?
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- One of the likeliest explanations, according
to experts, is a term more commonly associated with museums and archaeological
digs: artifact. The word, with its connotation of finding something after
searching and sifting, describes how many physicians regard statistics
showing increased incidence.
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- Until recent decades, many physicians
believe, brain tumors may have been misdiagnosed as dementia or stroke
because medicine didn't have the capability to detect many brain tumors.
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- In the 1970s, however, technology began
to change that. Computed tomography (CT) scans, which use X-rays to create
a three-dimensional image, became widely available and a valuable tool
in diagnosing brain tumors. Magnetic resonance imaging (MRI) scanning,
another powerful diagnostic tool, became widely available in the 1980s.
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- Many experts believe that the increasing
incidence is an artifact "dug up" by CT and MRI scans, and they
point out that the increase has occurred during the years when these technologies
have came into use.
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- "We are diagnosing cases more frequently,
not because the numbers are actually increasing, but because we have in
hand a safe technology to diagnose the problem," Mayo's Creagan said.
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- Living longer
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- Dr. Walter Hall, a University of Minnesota
neurosurgeon, also said much of the increase can be explained as an artifact
of better technology.
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- Hall said more people have access to
MRI and CT scans and the medical care necessary to diagnose brain tumors.
But he also said he believes that the aging population in the United States
and around the world may play a role. Because of better health care and
better health behavior, people are living longer than their predecessors,
he said.
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- Cancer primarily affects older people,
he said. It may be that many people who have brain tumors today would not
have developed them had they lived years ago, because they would not have
lived long enough.
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- "We are not predetermined to live
forever," Hall said. "If at age 70, you got a pretty good set
of heart and lungs, you've done the right things and haven't beaten up
your body, the only thing left . . . is cancer."
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- Not all physicians agree that the increased
incidence is simply an artifact of better technology.
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- Lowry, who became interested in brain
tumors after several acquaintances developed them, said that although CT
and MRI scans may explain the increases in the 1970s and 1980s, some physicians
believe that they can't account for the continued increases shown in the
1990s.
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- Lowry's article, published in the July
1998 issue of Archives of Neurology, investigated brain tumor symptoms
in the elderly. "It found that while the elderly patients had different
symptoms, they appeared to be diagnosed as promptly or even earlier than
younger patients," Lowry said.
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- Physicians who wrote an editorial accompanying
the study said Lowry's findings suggested that the increase couldn't be
explained only as an artifact.
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- "It seems that after the 1980s,
brain imaging ceases to have artifactual contributions to the increased
incidence of brain cancer," wrote Dr. Hassan M. Fathallah-Shaykh and
Donald D. McIntire, of the University of Texas Southwestern Medical Center.
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- Other explanations
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- Most experts concede that there may be
other not-yet-understood factors that are playing a role in the increase.
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- "For a long time, we thought that
the increases weren't meaningful, that they were the results of the improved
diagnostic technology. But more recently, some are are looking at this
and saying there's something else happening," said Dr. Eric Flores,
a University of Minnesota neurosurgeon. "While there are many schools
of thought, the bottom line is that it's very hard to figure out exactly
what is going on."
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- Studies of possible environmental agents
-- such as cell phones and electromagnetic fields -- haven't established
links between the agents and brain tumors, experts say. Other possibilities
studied and dismissed include diet, viruses, brain injury, hormones, alcohol
and smoking. And although there are dozens of Internet sites blaming aspartame
for brain tumors and other problems, experts say it's not likely that the
sweetener is responsible for the increased incidence.
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- Hall, of the University of Minnesota,
said the incidence began increasing before aspartame was used widely. And,
he noted, aspartame's influence also would show up a distinctive way: Aspartame
is consumed mostly in diet soda, which women drink more of than men. If
aspartame influenced incidence rates, more women than men would have brain
tumors.
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- Yet, Hall said, "the incidence is
the same in both genders."
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- Top priority
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- Despite differences of opinion, physicians
agree on the need not only to find an explanation for the increase, but
to develop better weapons to fight brain tumors.
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- "The bigger issue is: How do we
treat primary malignant brain tumors? How do we get better outcomes?"
Flores said. "That has to be the No. 1 priority."
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