Investigations of this method takes a team of scientists at
Ben-Gurion University and Soroka Medical Center in Israel.
The new method, which is still in development would
facilitate the diagnosis of cancer in its early stages through an infrared
device that radiates the fluid.
The irradiation results show the presence of malignant
cells, that during the initial stages of the disease are affected organs
separated from reaching the bloodstream.
Through a simple blood test could diagnose cancer in its
early stages in order to apply the respective treatment.
One of the advantages of the new method is the ease with
which the research is conducted, which will extend its use to a large number of
medical centers and hospitals.
The first clinical trials, which included more than 200
volunteers with lung cancer and ovarian cancer, were successful: in 90% of
cases the diagnosis was correct.
The goal is to expand the area of use of the device for
diagnosing an increased number of cancers.
What nobody tells you about cancer tests
If these tests can find cancer early, why some experts say
that sometimes cause more harm than good?
Read this before you make your next mammogram, PSA
measurement or colonoscopy.
Suzanne Bull was always afraid of getting cancer.
In part, his fear was because he lived in Marin County
(California), where the incidence of breast cancer is one of the largest in the
United States.
He was so determined to avoid that ate well, exercised and
each year was a mammogram.
In 2008, at age 54, received the news he feared most: an
ultrasensitive digital mammogram showed a suspicious lump in her left breast
and a biopsy confirmed it was malignant.
Luckily, the surgeon said, had discovered in time: it was a
ductal carcinoma in situ (DCIS), that is, cancer still limited inside a milk
duct, and according to the doctor maybe stay there because no DCIS often
becomes invasive.
Everything sounded good, Suzanne account until the
specialist said there was no way of knowing whether the tumor was of the type
that evolves slow, safe, or invasive.
Prescribed surgical removal of the breast lump, and also
advised to undergo radiation therapy and treatment with the drug tamoxifen.
After two weeks of anguish, Suzanne decided on surgery and
radiotherapy.
"I had to do what he could to stop the disease,"
he says.
Today, after two normal mammograms, feels very fortunate:
"I am glad to have had access to digital mammography, because cancer
detected much earlier."
Incredibly, some researchers believe that Suzanne had no
luck.
According to them, annual mammography is much less effective
than they usually believe women to reduce the risk of death from breast cancer,
and often leads to unnecessary treatment, especially in the case of DCIS.
As for the measurement of prostate specific antigen (PSA) in
men, these researchers say it may be more harmful than helpful in men without
symptoms of prostate cancer.
And other common means of cancer detection will inspire the
same confidence.
This view differs markedly from the campaigns of the
American Society for Cancer Control (SELC) and even the federal government of
that country, according to which detect and treat malignant tumors as soon as
possible is the most effective way to prevent deaths cancer.
Still, are increasingly dissident scientists (members of
prestigious institutions, authors of studies in respected medical journals) for
whom it is time to rethink our approach to cancer diagnosis.
So I believe that screening studies reveal many small
cancers that would never cause discomfort.
"The consequence is that cancer is diagnosed tens of
thousands of patients never develop the disease," says Dr. H. Gilbert
Welch, a specialist in cancer diagnosis and codirector of the Outcomes Study
Group Medical Center Veterans Administration in Vermont.
"Issued diagnosis, most people treated, and we know
that it can hurt."
Tamoxifen, used for breast cancer, promotes clot formation
in the lungs and remove operations for prostate cancer cause impotence in 60
percent of cases.
Screening tests themselves have risks: up to 0.5 percent of
those who undergo a colonoscopy suffer serious complications such as bleeding
and perforation of the colon.
Most people who are diagnosed with cancer definitely see
these risks in the price you pay for not dying from the disease.
"The reality is not so simple," says Welch.
The diagnostics are very effective to reveal tumors that
would never bother us, but not in time to discover the most lethal cancers and
faster development.
"The power of diagnostic studies to reduce the risk of
death has been exaggerated," said Dr. Floyd Fowler, president of the
Foundation for Informed Decision Making in Health, a nonprofit organization in
Boston.
How to fool cancer tests
The idea that testing can be useless or, worse, harmful,
maybe you think nonsense: after all, smaller cancers are easier to remove,
carry less risk of spread to other parts of the body, and this spread
(metastasis) depends largely malignancy.
It is certainly possible that a localized tumor mate: the
brain, for example, can wreak havoc if they grow healthy tissue compressed
against the skull.
Still, most life-threatening cancers only when some cells
break off and travel through the blood or lymph to another part of the body.
When this occurs, removal of the tumor and no cure, and no
more aggressive chemotherapy can kill malignant cells wandering.
Doctors believed that a tumor must reach a certain size
before they can metastasize, but today we know that is not always true, said
Dr. Barnett S. Kramer, associate director for disease prevention at the
National Institutes of Health in the United States.
"Some tumors spread quickly," when they consist of
a few million cells; seem much, but at this stage are less than the end point
of this paragraph, undersized for detecting most of the diagnostic tests.
Once you grow enough to appear on a test, and have spread.
The reverse of the coin is that many trials will never
reveal cancers that discomfort and can be left untreated.
This contradicts almost everything we thought we knew the
cancer, Kramer explains, because our knowledge is based on serious tumors.
If you compare the wide variety of cancers with an iceberg,
causing the symptoms represent only the portion above water, and for most of
history were the only ones who learned something.
Diagnostic studies allow us to see underwater and discover
even asymptomatic tumors.
We assume that eventually causing symptoms, but there is
increasing evidence that not always the case.
For example, in autopsies on American women of all ages who
died from causes other than breast cancer, found that nearly nine percent had
undiagnosed DCIS.
In Denmark, where mammography is not as common, autopsies
midlife women revealed that 39 percent had breast cancer undetected.
A 1989 study, Welch added, showed that 60 percent of men
over 60 have prostate cancer without knowing it, but only three percent of male
mortality due to this cause.
Therefore, screening for cancers give alarm or otherwise
unimportant to heal alone (since there spontaneously disappear).
It was suspected that Brandon Connor, now seven years old,
had cancer before birth.
The pregnancy was difficult and his mother, Kristin, a
lawyer for 35 years in Atlanta, was subject to frequent ultrasounds.
One of them revealed what looked like a tumor in the fetal
spine.
The tentative diagnosis was neuroblastoma, a cancer of the
nervous system.
Neuroblastoma can be of two types, one fatal, but without a
biopsy (very risky under the circumstances) it was impossible to know whether
it was this cancer, and less of what type.
The Connor chose to see if the tumor grew.
Physicians predicted that, in the best case, be reduced
during the first year of life of children. Not so.
After two years since Brandon had undergone more than 12
MRIs.
Eventually the doctors advised the intervention Connor, but
the day before the operation the surgeon asked one last scan, and neuroblastoma
had disappeared.
"We could not believe it," says Kristin.
Today
doctors know that many neuroblastomas heal spontaneously in the first years of
life.
"People told us we gave thanks to God that ultrasound
would have detected," says Kristin, but remembering the years of anguish
clarifies: "In retrospect, it seems rather a curse."
Side effects of diagnosis
Leave aside the fact that cancer treatment is an unnecessary
expense.
"Many oncologists know that some of his patients have
suffered serious side effects and even died because of a treatment that may not
be needed," says Dr. William C. Black, professor of radiology at
Dartmouth-Hitchcock Medical Center. Certainly no one intentionally prescribe
unnecessary treatments, but as is often difficult to determine whether or not a
patient requires care, we prefer to err on before default.
Take the case of George Brown, who was diagnosed with
prostate cancer in 2008, when he was 75 and still practiced as a lawyer in
Denver.
Your doctor prescribed Lupron to block the secretion of
testosterone, a hormone that many prostate cancers need to grow.
"I did not know that the Lupron is a chemical
castration" he recalls. '
I fell into extreme depression, I came bouts of cold and
heat, crying for everything. "
Radiation damaged her rectum and urinary and fecal
incontinence occurred.
Soon you will have to take another testosterone blocker.
Nevertheless, Brown believes that treatment saved his life,
which unfortunately can not be confirmed in cases such as yours.
The truth is that most men who are diagnosed with this
cancer are subjected to invasive treatments, although statistics indicate that
many could safely opt for a "watchful waiting": observe the evolution
of cancer Ape measurements, and treat only if it starts to grow rapidly.
Diagnosis saves lives?
For many people, even serious side effects such as those
suffered Brown would be worth if the risk of dying from cancer was reduced: do
not forget that this is the purpose of testing.
However, only the Pap ever has. According to the SELC,
between 1955 and 1992 this test fell 74 percent mortality from cervical cancer,
which has continued to decline from year to year.
No other test has achieved so much.
It is unclear whether the measurement of Ape has significantly
reduced mortality from prostate cancer.
Between 1975 and 2005 (latest year for which figures are
available), mortality decreased from 31 to 24.6 per 100,000 men.
Although a significant drop, many experts doubt be
attributed entirely to the test, especially if one considers the result of a
"natural experiment" occurred in Seattle (Washington), and in the
state of Connecticut in the late eighties.
Between 1988 and 1990 Medicare patients in Seattle turned
five times more than those of Connecticut Ape measurement, and also underwent
most to surgery and radiotherapy for prostate cancer.
However, a follow-up to 1997 conducted revealed that
prostate cancer mortality was equal in both groups.
"Measuring your APE seems sensible, but it is
ineffective," said Dr. Nortin M. Hadler, professor of medicine at the
University of North Carolina and author of a book on overtreatment.
The use of mammography is also lower than assumed many
patients and many physicians.
Although its effectiveness has been hotly debated, a careful
analysis in 2005 indicated that only reduced by 15 percent mortality from
breast cancer, says Kramer.
In other words, a woman of 60 who have a mammogram every
year reduced from 0.7 to 0.6 percent their risk of dying from this cancer in
the next decade.
Colonoscopy (colon observation with an endoscope) also
allows the doctor to remove polyps (growths that can become cancerous) it
finds.
The most favorable calculations indicate that this technique
reduces mortality from colon cancer by up to 60 percent, but do not know for
sure for lack of study.
The reduction seems huge, until you consider that the risk
of dying from colorectal cancer is quite small: in women, 2.1 percent, and 2.3
percent in men.
Reduce by 60 percent the risk of 2.3 percent means that it
decreases to 0.9 percent: an undeniable benefit, but perhaps not large enough
to offset the disadvantages.
Tests done or not?
The answer depends on many factors, including your age, do
you suffer diseases and health aspect of what you value most.
Dr. Dennis Fryback committee comprised of the United States
Preventive Services, an expert panel convened by the government of that country
to issue recommendations on screening tests.
Although the committee advises people aged 50 to 75 years
performed a colonoscopy every 10 years, Fryback, 61, believes that if the test
is unnecessary.
Review and, among other things, because he has no family
history of colon cancer. If it did, your risk of suffering would be greater, as
is your chance to benefit from the test.
He also knows that to have this test must take laxatives
during the previous day to clean the colon, the procedure poses the risk of perforation,
and that this risk increases with age.
Fryback weighed the potential reduction in the risk of dying
from colon cancer, and other diseases.
In 2008 he suffered a heart attack and dies of suspected
heart before a colon polyp might threaten his life.
For him, colonoscopy is "a very expensive lottery
ticket.
Maybe earn some time, but most likely will not win anything.
"
By analyzing your chances, Fryback has the advantage of
being an expert in making medical decisions.
Laymen know much less health statistics, but there are
documents (brochures, videos, interactive Internet programs and other support
for the patient's decision-making) that can help us choose the most convenient
option.
Some include interviews with cancer survivors and people
considering whether to undergo screening.
Using aids decision making has not been widespread, but some
medical centers and insurers and offer.
Suzanne Bull turned to one form of DVD before deciding to
undergo radiation therapy for breast cancer. "Show me much good," he
says.
Researchers and doctors hope to develop better screening
tests, able to distinguish between cancers that should be treated and those
not.
Meanwhile, say, the decision to undergo studies should be
based on the values of the person and their ability to cope with uncertainty.
"We are more afraid of dying of a disease that doctors
too scrupulous hands," concluded Black.
To submit to testing we run two risks.
0 comments:
Post a Comment