This malignancy has become preventable, at least in many cases, because the way that it comes about is generally slow, and in discrete stages. The intermediate stage is a benign polyp called an adenoma, something that can be seen, and removed, with a proceedure called colonoscopy.

• "Interruption of this adenoma-carcinoma sequence with colonoscopy and polypectomy reduces the incidence of CRC by as much as 90%." Saini SD, Kim, HM and Schoenfeld P:Incidence of advanced adenomas at surveillance colonoscopy in patients with a personal history of colon adenomas: a meta-analysis and systematic review. Gastrointestinal Endoscopy - Volume 64, Issue 4 (October 2006).