[header] How to prepare for a colonoscopy [title] Understand the purpose of a colonoscopy. [step] Colonoscopy is the best technology available for determining whether cancerous or precancerous growths called polyps are present in the colon. Early detection can enable patients to get the treatment they need to prevent growths from advancing to the next stage. 
The american cancer society recommends that people over age 50 should have a colonoscopy every 10 years. Those who are at increased risk of getting colon cancer should have the test done more frequently.