Gene Test Might Predict Colon Cancer's Return01/19/11
TUESDAY, Jan. 18 (HealthDay News) -- A genetic test seems able
to identify which people with stage II colon cancer face a higher
risk of recurrence, German researchers report.
This would be a huge help to doctors in determining which
patients need follow-up treatment after initial surgery and which
do not, and it would be an improvement on existing ways to predict
recurrence, according to cancer experts.
"Eighty percent of stage II colon cancers are cured by surgery alone," said Dr. Jennifer Obel, an American Society of Clinical Oncology (ASCO) official and an assistant clinical professor of medicine at the University of Chicago, who spoke at a Tuesday news conference to announce the findings. "Only a small percentage develop metastases. We don't want to treat everyone with chemotherapy that will only benefit a few and expose them to unnecessary side effects."
"This is another example of trying to personalize treatment for cancer," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La.
These results and others are scheduled to be presented this
weekend at the 2011 Gastrointestinal Cancers Symposium,
co-sponsored by ASCO, in San Francisco.
To develop the ColoPrint test, researchers scanned the entire
human genome to identify 18 genes that were associated with the
risk of a recurrence in patients diagnosed with stage II
In the study, 233 patients who had already undergone surgery for
stage II or stage III colon cancer underwent the test and were
followed for an average of eight years.
Only 5 percent of patients with stage II cancer identified as
low-risk by the test had a recurrence within five years, vs. 20
percent of those who were classified high-risk.
"Patients who ColoPrint identified as high-risk had a 4.1-fold increased risk of developing a distant metastasis compared with those patients who had been identified as low-risk," said study author Dr. Robert Rosenberg, a surgeon and an assistant professor at University Hospital, Technical University, in Munich. "Our studies confirm previous studies. ColoPrint facilitates the identification of patients who might not need additional therapy."
The results are similar to those found in earlier studies of the
test, one of which was published in the
Journal of Clinical Oncology last year; a larger, prospective
trial is now underway.
Another test that looks at 12 genes, called Oncotype DX, is
already licensed in the United States., said Brooks. "The question
of which test is better is unknown at this time," he added.
Oncotype DX costs upwards of $3,000, and Rosenberg was unable to
provide any information on what the cost of the new test, if
licensed, would be.
Although Rosenberg did not have any financial disclosures, other
authors reported ties with Agendia, which makes the test.
In other news from the conference:
- A Phase II trial in 52 patients with stage II and stage III
anal cancer found that chemotherapy with a more targeted mode of
radiation (called intensity-modulated radiation therapy or IMRT)
had the same benefit as conventional radiotherapy as far out as two
years after treatment. IMRT has the advantage of fewer side
- Another Phase II trial showed that the targeted therapy Nexavar
(sorafenib) might be useful in patients with gastrointestinal
stromal tumors (GIST) who have failed or become resistant to other
therapies, particularly Gleevec, a similar targeted therapy; it
halted cancer progression in two-thirds of the patients for up to
three years. Nexavar did, however, have a number of side effects
such as hypertension, which required 63 percent of patients to go
to a lower dose of the drug.
- Using positron emission tomography (PET) imaging may help
predict the prognosis and guide treatment of patients with locally
advanced cancer of the esophagogastric junction. The researchers
also found that patients who didn't do well with chemotherapy
didn't respond to more radiation, either.
The National Cancer Institute has more on
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