One or more of the following tests to diagnose rectal cancer may be performed:
- High-sensitivity fecal occult blood test (FOBT) - checks for blood in three consecutive stool samples.
- Flexible sigmoidoscopy - uses a flexible, lighted tube (sigmoidoscope) to look at the interior walls of the rectum and part of the colon.
- Colonoscopy - uses a flexible, lighted tube (colonoscope) to look at the interior walls of the rectum and the entire colon.