Celecoxib reduces the incidence of colon adenomas and can be used safely by patients without underlying cardiovascular risk factors, according to a presentation at the annual meeting of the American Association for Cancer Research.

Researchers presented five-year data from the phase III Adenoma Prevention with Celecoxib (APC) trial, which studies chemoprevention of colon adenomas with the selective Cox-2 inhibitor.

"There has been a significant amount of negative press about Cox-2 inhibitors including celecoxib, and clearly these drugs are risky for some patients. However, our study also shows that for patients without major cardiovascular risk factors, celecoxib at low doses protects against high-risk lesions that can lead to colon cancer," said Monica Bertagnolli, MD, associate professor of surgery at the Brigham and Women's Hospital.

Bertagnolli was lead researcher on the APC trial, which randomized 2,035 patients to 200 mg twice-daily (400 mg) celecoxib, 400 mg twice-daily (800 mg) celecoxib or placebo.

At three years, patients taking 400 mg celecoxib daily had a 29-percent reduction in adenomas, and patients taking 800 mg daily had a 38-percent reduction. Advanced adenomas were reduced by 55 percent with 400 mg and 63 percent with 800 mg.

After three years, patients stopped taking celecoxib and were followed for another two years to assess safety and effectiveness. Even after two years off medication, the five-year rate of advanced adenoma was reduced by 41 percent among patients taking 400 mg and 26 percent among patients taking 800 mg.

Cardiovascular events were more common in patients taking celecoxib: Compared with the placebo group rate of 3.8 percent, the 400-mg group had a 6 percent rate and the 800-mg group had a 7.5 percent rate.

However, when researchers looked at cardiovascular risk factors, they found that patients with none at baseline had rates of cardiovascular adverse events of 0.9 percent (placebo), 3.9 percent (400-mg) and 1.9 percent (800-mg). Cardiovascular risk factors included smoking, high cholesterol levels, hypertension, diabetes, known atherosclerosis, and age over 65 years.

If a patient had one risk factor, the risk was 2.2 percent in the placebo group, 3.7 percent in the 400-mg group and 4.9 percent in the 800-mg group.

Greater cardiovascular risk was observed among patients who had at least two cardiovascular risk factors at baseline: 5.9 percent risk for placebo, 8.2 percent risk for 400 mg, and 11.2 percent for 800 mg.

"This new data allows us to carefully select patients who can benefit from this drug," Bertagnolli said. "Although it should be used with caution, those patients with a high risk for colon cancer and a low risk for cardiovascular disease are going to receive significant benefit."