People
With Blood Cancers Living Longer With New Therapies
September Is Leukemia, Lymphoma, And Myeloma
Awareness Month
For blood cancers such as
leukemia, lymphoma, and myeloma, chemotherapy has been the first line
of defense until recently.
But new "molecularly targeted drugs"
now are being hailed as precise and powerful weapons against cancers
that are notoriously hard to treat. This new therapy attacks diseased
cells directly and produces fewer side effects in the process.
"Unlike solid tumors, where surgery
can be used to remove the tumor at an early stage and the patient might
not be treated with anything else, we can't do that in blood cancers,"
explains Alan Kinniburgh, vice president of research at the Leukemia
& Lymphoma Society (LLS).
"This was the first place chemotherapy was brought
to bear and was successful," he says. "We're now at a point
from where in 1960 about 4 percent survived longer than five years and
now 85 percent do," Mr. Kinniburgh says.
To push beyond that 85 percent mark, researchers are
pouring their energy into the development of these molecularly targeted
drugs.
To heighten awareness of these developments,
the LLS is observing September as Leukemia,
Lymphoma, and Myeloma Awareness Month.
Leukemia refers to cancer of the bone marrow and blood
cells. The two major categories are myelogenous and lymphocytic. Each
of these can be further subdivided into acute (with a rapid onset and
progression) and chronic (which develops and progresses more slowly).
Lymphomas are cancers that arise when lymphocytes -
a type of white blood cell - become malignant. The two main types of
lymphoma are Hodgkin's and non-Hodgkin's.
Myeloma affects the plasma cells (white blood cells
found primarily in the bone marrow) and interferes with the body's immune
system.
The cause of these cancers is uncertain, although they
are thought to arise when a single cell with a genetic flaw starts replicating
uncontrollably.
Targeted
Drugs Equate With Success
While chemotherapy and other conventional
treatments are still being used, the breakthroughs are coming as a result
of molecularly targeted drug therapy.
"We've really spent a lot of time in the last couple
of decades finding altered genes in cancer and now we're actually starting
to develop molecular-targeted therapy to go after these altered genes,"
says Dr. Donald Small, of the Johns Hopkins University School of Medicine.
Specifically, scientists are looking at a class of frequently
mutated genes called tyrosine kinases, which seem to be involved in
many of the blood cancers, Dr. Small says.
Chronic myeloid leukemia, or CML, for instance, involves
a genetic flaw in one of these genes that produces an abnormal protein.
This triggers a signal that pushes cells to start reproducing.
A new drug, Gleevec®, goes inside the abnormal protein
and commands it to stop sending the signal. Because the drug is so finely
targeted, it has few side effects. Gleevec® now appears to be emerging
as the drug of choice for CML, Dr. Small says.
Similarly promising research is taking place with acute
myelogenous leukemia, or AML, a disease whose cure rate hovers at 20
percent to 30 percent.
"We really need new types of therapies and it may
well be that, when chemo (chemotherapy) is combined with some of the
targeted therapies, we could see a big impact," Dr. Small says.
Dr. Small and other researchers around the country are
currently conducting trials with new molecularly targeted drugs that
inhibit another tyrosine kinase gene, this one called FLT-3.
"There are patients who are having responses,"
Dr. Small reports.
In the case of AML, however, more than one drug will
probably be needed to affect the multiple genes that are at fault.
"In chronic phase CML, it's probably a single gene,
so it's a lot easier to target; you're basically hitting the whole disease,"
Dr. Small says. "In AML, there are probably three or four or more
altered genes."
Other
New Therapies Take Hold
Chemotherapy and radiation have both been
around for half a century but can entail significant side effects.
"They kill growing cells and they kill the fastest
first and that's fine, but it's kind of a blunt instrument when it's
used," Mr. Kinniburgh says.
A newer approach is called immunotherapy, also targeted
but not usually considered molecularly targeted. This involves developing
antibodies that attack part of the cell surface, causing the cell to
die. These are also called monoclonal antibodies.
And vaccines could help the patient's own immune system
fight off blood cancer. No vaccines are yet approved, though some are
in advanced clinical trials.
Many patients also need bone marrow transplants, which
seek to replace a person's depleted healthy blood-forming cells with
another person's.
"It's kind of a hybrid system of using someone
else's immune system to reconstitute your own immune system after very
vigorous chemo (chemotherapy) and/or radiation," Mr. Kinniburgh
explains. "You just have to watch out for those cells attacking
the body because there are differences. It kills patients every day."
Finally, there have been some recent reports that postmenopausal
women who take aspirin regularly may have a lower incidence of acute
leukemias.
Mostly, though, the world is moving in the direction
of highly targeted treatments.
"Over time it will be more and more designer-type
therapy," Dr. Small says. "Eventually, it may turn out that
a patient comes in with a certain type of tumor, we take cells, see
what genes are altered and pull compound A for this mutation and compound
C for that one. It will be very, very specific and very much designer-type
therapy."
Always consult your physician for more information.
Online
Resources
American
Cancer Society
American
Heart Association
Centers
for Disease Control and Prevention (CDC)
Leukemia
& Lymphoma Society
National
Institutes of Health (NIH)
National
Women's Health Information Center
US
Department of Heath and Human Services
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September 2003
In
This Issue:
People
With Blood Cancers Living Longer With New Therapies
Targeted
Drugs Equate With Success
Other
New Therapies Take Hold
Substance
in Tomatoes Aids in Heart Disease Prevention
Online
Resources
Other
Resources:
Find
a St. John's Mercy Physician
St.
John's Mercy Center for New Health Options
Mental
Health Information
St.
John's Mercy Classes and Programs
Substance
in Tomatoes Aids in Heart Disease Prevention
Just
one serving a day of tomato-based foods such as pizza or tomato
sauce could lower your risk for heart disease by as much as 30
percent, contends a new Harvard University study.
"The results are
pretty enticing," says study author Dr. Howard Sesso, of
the Harvard School of Public Health and Brigham and Women's Hospital
in Boston. "They're encouraging enough for us to do more
studies."
The findings appear
in the Journal of Nutrition.
Dr. Sesso and his colleagues
reviewed the diets of approximately 40,000 women from the ongoing
Women's Health Study, which was begun 11 years ago to follow women
who, at the time, were free from cancer and cardiovascular disease.
The researchers controlled
for factors such as age, family history, smoking status, and other
health indicators.
They found that women
who consumed seven or more servings of tomato-based foods a week
- including tomato juice, tomatoes, tomato sauce, or pizza - had
a nearly 30 percent reduction in risk for cardiovascular disease
compared with women who ate less than one and one-half servings
a week.
The study was sparked
by research that has shown a connection between an increase in
the diet of the antioxidant lycopene and a reduction in risk for
prostate cancer, Dr. Sesso says.
Since tomatoes are a
rich source of lycopene, he and his colleagues were interested
to learn if the same antioxidant qualities, when eaten in tomatoes,
might also lower heart disease risk.
Interestingly, however,
when the researchers tabulated the result, the lycopene intake
itself was not significantly associated with reduced heart disease
risk.
However, when they looked
at food intake, as measured by self-reported servings, there was
a clear cardiovascular benefit for those who consumed the tomato-based
products on a regular basis.
"Our study suggests
preliminary evidence that consuming a number of servings of tomato-based
foods per week may lower the risk of cardiovascular disease,"
Dr. Sesso says.
Connie Diekman, director
of university nutrition for Washington University in St. Louis,
finds the study promising, both because the large number of women
surveyed make the results significant and because the findings
concur with other work on the topic.
"The results may
still be inconclusive, but the indication that lycopene/tomatoes
may aid in the prevention of disease continues to evolve,"
Ms. Diekman says. "I would encourage people to take these
results and add them to the growing list of studies that point
to the benefits of more fruits, vegetables, and whole grains."
Dr. Sesso points out
that those people who showed the benefit from eating the tomato
foods might just have an overall healthier diet than those who
had fewer servings of tomatoes.
"It could be the
diet itself, one that includes more fruits and vegetables,"
he says. "Those people would have a better cardiovascular
profile."
"It's hard to be
specific," Dr. Sesso says of the findings, "but there's
a potential that regular servings of tomatoes can have a dramatic
effect on cardiovascular risk."
Always consult your
physician for more information.
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