Assertion: colonoscopy | /r/HasProperty | essential modality
Facets:
value: for surveillance
type: PURPOSE
value: for colon cancer screening
type: PURPOSE
Source sentences:
text: Colonoscopy is an essential modality for colon cancer screening and surveillance, and several studies found that the removal of adenomatous polyps using colonoscopy decreased not only the incidence, but also the mortality, of colorectal cancer (1-3).