Through a biopsy and colonoscopy, your doctor can confirm the status of your polyps and check for any proximal lesions in the rectum and colon. While adenomatous polyps may be precursor lesions to colorectal cancer and are larger in size, hyperplastic polyps are usually smaller than 5 mm wide and non-threatening. Polyps larger than one centimeter are considered risky and should be addressed immediately, as polyps that are not removed will continue to grow and can potentially become cancerous.