A cheap headache pill may not only help prevent colon cancer, but may turn out to be an effective therapy, U.S.-based researchers said.

Mice with cancer that were given small daily doses of ibuprofen had smaller tumors and were less likely to die of colon cancer, they told a meeting.

"Now we want to do some more studies," said Dr. Michael Wolfe, a gastroenterologist at the Boston University School of Medicine, who led the study.

"What was really, to us, remarkable is the dose we used in these animals is equivalent to 100 mg of ibuprofen in a human."

That is about half the amount contained in a standard tablet of ibuprofen.

Several studies have shown that people who take aspirin, ibuprofen and related drugs called non-steroidal antiinflammatory drugs, or NSAIDs, have a lower risk of colon cancer.

The mechanism seems to be compounds called COX-1 and COX-2, both of which NSAIDs interfere with.

But Wolfe said no one had tested NSAIDs as a potential cancer therapy.

Ibuprofen seemed to affect tumor cells in lab dishes, so he tried using laboratory mice that had been infected with colon cancer cells. These mice always develop tumors and die if not treated.

They treated the mice for 2f days with either ibuprofen alone, or with ibuprofen added to the standard colon cancer

drugs irinotecan.

By day 50, all the untreated mice had died. But 20 percent of the mice treated with ibuprofen alone died, compared to 20 percent given Camptosar and just 10 percent given ibuprofen plus irinotecan. But 70 percent of the mice that got 5-fluororacil alone or with ibuprofen died.

Ibuprofen and 5-fluororacil seem to interfere with one another, Wolfe said. The findings were presented on Wednesday to a meeting in New Orleans of

cancer and digestive experts called Digestive Disease Week.

"I'd love to see a study done for the actual treatment of cancers," Wolfe said. But because ibuprofen is cheap, he feared it was "not sexy enough" for any big drug company to sponsor.