SUNDAY, June 6, 2004 (HealthDayNews) -- An enzyme biomarker that may help doctors predict how colon cancer patients will respond to a specific chemotherapy regimen has been identified by Fox Chase Cancer Center researchers.
This enzyme, thymidine phosphorylase (TP), is found in some, but not all, cancers.
The study of 67 people, aged 40 to 81, with colorectal cancer found those whose tumors expressed TP had a much higher response rate to a chemotherapy regimen with the drugs capecitabine plus irinotecan.
The response rate for those whose primary tumors tested positive for TP was 65 percent, compared with 27 percent for those whose tumors tested negative for the enzyme. The response rate was 61 percent for people with metatastic tumors that expressed TP, compared with 14 percent for those who didn't have TP in metatastic tumors.
"These data suggest that TP expression may be useful as a marker in predicting a positive response to chemotherapy with capecitabine plus irinotecan for colorectal cancer patients," Dr. Neal J. Meropol, director of the gastrointestinal cancer program at Fox Chase, said in a prepared statement.
"With that information, we can begin personalizing treatment. If we know the enzyme is present to activate the drug, we may be able to identify those patients who should receive capecitabine," Meropol said.
He presented the study June 6 at the annual meeting of the American Society of Clinical Oncology in New Orleans.
More information
The American Cancer Society has information about colorectal cancer.
