Advances in Colorectal Cancer
New drugs show promise, but more research needs to be done.
Colorectal cancer is the third most common cancer in the U.S.
and the second most common cancer killer. But in the last few years,
researchers have made new discoveries that may dramatically improve the
prognosis for people living with the disease.
"This is a very exciting moment in the treatment of
colorectal cancer," says Meg Mooney, MD, a senior investigator at the
Clinical Investigational Branch at the National Cancer Institute. "For a
long time, we just weren't able to do much in terms of making a real difference
in a patient's care. But now we have new medications that really show
improvement in the survival of people with the disease."
Admittedly, there's no miracle cure out there yet and a great
deal of research still needs to be done. But these new discoveries are a cause
for real hope.
For decades, Mooney says, the main drug treatment for
colorectal cancer was limited to two drugs, Adrucil and Wellcovorin. But
beginning in 2000, things began to change.
In that year, the FDA approved the chemotherapy drug Camptosar
for first-line use in people with metastatic colorectal cancer -- cancer that
has spread outside the colon and into other parts of the body. Studies show
that people using a combination of Camptosar with other drugs lived longer than
those using traditional chemotherapy.
Then more recently, a study by the National Cancer Institute
showed that another chemotherapy drug, Eloxatin, was more effective than
Camptosar when both were combined with the traditional chemotherapy drugs.
"After relying on the same two drugs for years, all of the
sudden we have two more drugs that can help people with metastatic colorectal
cancer live longer," Mooney tells WebMD. "In the last four years, a lot
Two news colorectal cancer drugs -- Avastin and Erbitux -- were
approved by the FDA in February.
Antiangiogenesis, at Last?
The promising trials of the drug Avastin have been one of the
biggest stories in the treatment of colorectal cancer. A recently published
study of people with metastatic colorectal cancer found that those who received
Avastin in addition to standard chemotherapy lived about four months longer
than people who just received standard chemotherapy. This might not seem like a
big improvement, but the study involved people with advanced colorectal cancer
who often don't respond very well to treatment.
Avastin is the first of a long-awaited and new kind of cancer
treatment, so-called angiogenesis inhibitors, which starve tumors by blocking
blood vessel formation in them.
For many cancer researchers, antiangiogenesis has been the Holy
Grail of drug development. Cancer cells need blood flow to grow, and the
formation of new blood vessels is called angiogenesis. For decades, researchers
have been working on a way to prevent the formation of new blood vessels.