Colorectal Cancer Screening in Cystic Fibrosis

1. Adults with CF ages 18 - 75 years and due for a routine screening or surveillance colonoscopy for colon cancer 2. Cystic Fibrosis diagnosis, defined by a sweat chloride test result ≥ 60 mmol/L (may be of historic value), and/or documented CF-causing CFTR mutations and clinical features of CF 3. Capable of understanding the purposes and risks of the study in English or Spanish and willing to participate and sign informed consent 4. Referred for screening or surveillance colonoscopy for CRC (current standard of care) and willing to undergo colonoscopy and stool testing 5. Able to access the Internet to complete self-administered surveys

1. Any condition that, in the opinion of the site PI, introduces undue risk by participating in this study 2. Incapable of understanding the purposes of the study or informed consent for any reason 3. Pregnancy 4. Active inflammatory bowel disease as defined by a prior diagnosis of Crohn's Disease or Ulcerative Colitis, based on both clinical and histopathologic findings and the individual currently on medical therapy for Crohn's disease or Ulcerative Colitis. 5. Personal history of colon cancer diagnosis and treatment within 5 years of enrollment 6. Symptoms that merit colonoscopy for diagnostic purposes rather than as screening for CRC 7. Known history of familial colon cancer syndrome that has been confirmed by previous genetic testing