“Substances explored as chemopreventive agents in colorectal cancer include: (1) the nonsteroidal anti-inflammatory drugs (NSAIDS), which may inhibit … adenomas by their inhibition of cyclooxygenase and decrease of prostaglandin synthesis; (2) antioxidants, such as vitamin E or C, … carcinogenic substances ; and (3) folate and calcium, … cell growth and replication.”