The investigators hypothesize that the combination of eflornithine and sulindac will be effective in reducing a three-year event rate of adenomas and second primary colorectal cancers in patients previously treated for Stages 0 through III colon or rectal cancer.

This will be a randomized, controlled pilot trial of patients with histological documentation of primary colon or rectal adenocarcinoma with resectable cancer, who have not received any treatments for cancer. If patient is a candidate for surgical resection, with no planned neoadjuvant chemotherapy, then the patient is eligible. All eligible subjects will be consented prior to surgery.