Skip to Main Content

An official website of the United States government


This section concerns collection of data for colorectal cancer only. For polyp and adenoma data collection, see Diagnostic Procedures (Colorectal).

The PLCO trial confirmed diagnoses of colorectal cancer through medical record abstraction (MRA) of participants suspected by the trial to have colorectal cancer. MRA was triggered by:

  • A self-report of colorectal cancer on an Annual Study Update (ASU)
  • Abnormal suspicious FSG screening
  • Death certificate indicates colorectal cancer
  • No trial indication of colorectal cancer, but Death Review Committee suspects colorectal cancer based on other indicators
  • Relative informs screening center of participant's cancer (this is infrequent)

Note that if the MRA process does not find records indicating colorectal cancer diagnosis, even if a source such as a death certificate indicates colorectal cancer, the colorectal cancer is not considered confirmed.

Cancer diagnosis data can be obtained within the Colorectal dataset.

Summary Available Data
  • Data for ~2400 cancers (300 screen-detected)
  • Intervention arm statistics:
    • ~1000 cancers
    • Median age at dx: 70
    • Median years into study at dx: 5.3
  • Control arm statistics:
    • ~1300 cancers
    • Median age at dx: 70
    • Median years into study at dx: 5.8
  • Cancer confirmation status (confirmation, report only, no cancer, etc.)
  • Days from randomization to diagnosis
  • Screen-detected versus not screen-detected
  • Tumor location (e.g., proximal, sigmoid)
  • Cancer stage
  • Histology