This phase III trial studies how well eflornithine works compared to sulindac in preventing the return of the disease (recurrence) of high-risk adenomas and second primary disease in patients with stage 0-III colon or rectal cancer. Drugs used in chemotherapy, such as eflornithine and sulindac, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Eligibility includes being at least 18 years old and:
•Patients must have a history of stage 0, I, II or III colon or rectal adenocarcinoma that has been treated per standard care with resection alone or in combination with radiation or chemotherapy; adjuvant chemotherapy and radiation therapy (RT) treatment must have been completed at least 30 days prior to registration
•Patients with history of segmental resections are eligible (i.e. right colectomy, extended right colectomy, transverse colectomy, left colectomy, extended left colectomy, sigmoid colectomy, low anterior resection, abdominoperineal resection);
•Patients must be registered between 120 days and 456 days (inclusive) of primary resection; patients must show no evidence of colorectal cancer based on post-operative colonoscopy (performed at least 120 days after the colon or rectal resection date and prior to registration); patients with adenomas detected at the one-year postoperative colonoscopy are eligible if all adenomas have been completely removed
