The combination of the difluoromethylornithine (DFMO) and sulindac reduces the rate of colon adenomas (growths or polyps) by up to 95% among patients who have had prior colon polyps. These results were presented as a late-breaking abstract at the 2008 annual meeting of the American Association for Cancer Research.
Adenomas are abnormal growths that often arise in the colon and have the potential to turn cancerous. Individuals who have adenomas are at an increased risk of developing future adenomas and are therefore encouraged to undergo more stringent screening, such as colonoscopy. Adenomas are removed during a colonoscopy to prevent the possibility that they may progress to cancer.
Researchers from the University of California Irvine recently conducted a clinical trial to evaluate DFMO and sulindac in the prevention of adenoma recurrences. DFMO aids in reducing excess cellular replication, and sulindac is a non-steroidal anti-inflammatory agent. Although DFMO had demonstrated promising activity in prior studies, it also caused temporary change in hearing (ototoxicity), which halted its progression through clinical trials. Further studies, however, demonstrated that lower doses of DFMO limited ototoxicity, allowing for its reemergence into clinical research.
This trial included 375 patients who had a history of colon adenomas measuring at least 3 millimeters in diameter. These patients received either DFMO/sulindac or placebo (inactive substitute) for three years.
- The risk of a recurrence of adenomas declined by 70% among patients treated with DFMO/sulindac compared with those who received placebo (12.3% versus 41.1%, respectively).
- Advanced adenomas occurred in only 0.7% of patients treated with DFMO/sulindac compared with 8.5% of patients who received placebo.
- Multiple adenomas were found in only 0.7% of patients treated with DFMO/sulindac compared with 13.2% of patients who received placebo.
- Side effects were not significantly different between the two groups of patients.
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The researchers concluded that treatment with DFMO/sulindac appears to drastically reduce rates of adenoma recurrence among individuals who have been diagnosed with prior colon adenomas. Further study of this drug combination is warranted.
Patients with a history of colon adenomas may wish to speak with their physician regarding their individual risks and benefits of participation in a clinical trial further evaluating DFMO/sulindac or other novel therapeutic strategies. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.eCancerTrials.com.
Reference: Meyskens FL, et al. Marked efficacy of difluoromethylornithine plus sulindac in reducing recurrent colorectal adenomas in patients with prior adenomas: Results of a randomized, placebo controlled, double-blind Phase III trial. American Association for Cancer Research Meeting 2008. Abstract LB-142.
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