Colorectal cancer kills 55,000 Americans yearly, yet 68% of these deaths are preventable through screening—and colonoscopy remains the only cancer screening test that detects and removes pre-cancerous lesions before malignancy. Peter Atia explains the biology of CRC, why early-onset cases are rising in younger adults, how to ensure high-quality colonoscopy, and how non-invasive alternatives compare. Colorectal cancer follows a decade-long progression from normal tissue to benign polyp to pre-cancerous lesion to malignancy, creating a uniquely wide window for prevention through early detection.