2004-3-9
This is the VOA Special English Health Report.
There is an expression that describes the traditional three steps
that doctors use to treat cancer: "cut, burn and poison." Cut out
the growth. Burn the cancerous cells with radiation. Poison those
that remain with chemotherapy drugs.
More than thirty years ago, a young American doctor proposed
another way. Doctor Judah Folkman thought cutting the blood supply
to cancers could block their growth. For a long time, many other
scientists dismissed this theory.
But, last month, the United States Food and Drug Administration
approved the first drug that works the way he proposed. The drug is
called Avastin. The Genentech company developed it to lengthen the
lives of people with colon cancer that has spread in the body. It
does not cure the disease, however.
To test the drug, some patients received both Avastin and
chemotherapy chemicals. Others received only chemotherapy. The
people who had both generally survived for twenty months. That was
about five months longer than those on chemotherapy alone.
Avastin is a genetically engineered protein. It connects with a
protein in the body that helps blood vessels grow. That protein is
known as V.E.G.F., vascular endothelial growth factor. Blocking this
growth factor can interfere with the supply of blood to the cancer
and starve the cells.
Avastin is designed to target the weak places in cancer cells. It
does not damage normal tissue. Chemotherapy drugs kill cancer cells,
but usually also kill other cells. This can cause infections along
with stomach and intestinal problems.
Today, Judah Folkman is a professor at the Harvard Medical School
in Cambridge, Massachusetts. During the nineteen-sixties he worked
at the Bethesda Naval Hospital in Bethesda, Maryland. Doctor Folkman
thought that cancers put out some kind of material that made new
blood vessels form. He thought it might be possible to develop new
treatments if the vessel growth could be blocked. Today other drugs
are also being tested to see if they can stop the formation of blood
vessels.
Avastin is one of three new drugs approved for colon cancer in
the past two years. But some doctors also note that these new
medicines cost a lot more than older treatments.
This VOA Special English Health Report was written by Jerilyn
Watson.