A physical examination rarely shows any abnormalities, although
an abdominal mass may be present. A rectal examination may reveal a mass in patients with
rectal cancer, but not colon cancer.
Colon Cancer diagnosis - flex scopes
A colonoscopy is a procedure
for viewing the interior lining of the large intestine (colon) using a small camera called
a colonoscope (which is a flexible fiber-optic tube).
A colonoscopy or sigmoidoscopy may reveal evidence
of cancer. However, only colonoscopy (NOT sigmoidoscopy) examines the entire colon.
A colonoscopy is a procedure for viewing the interior lining of the large intestine
(colon) using a small camera called a colonoscope (which is a flexible fiber-optic tube).
A sigmoidoscopy is a similar procedure that only look at the rear half of the colon.
Colon Cancer diagnosis - Fecal occult blood test.
A fecal occult blood
test (FOBT) may detect small amounts of blood in the stool, a possible indicator of
colon cancer. However, this test is often negative in patients with colon cancer. Not all
polyps bleed, and not all polyps bleed all the time. That is why a FOBT must be used with
one of the other more invasive screening measures (e.g., colonoscopy or sigmoidoscopy).
Finally, a positive FOBT doesn't necessarily mean the person has cancer -- "false
positives" can be caused by some medications and other factors.
A blood count may reveal evidence of anemia with low iron levels. A CT scan may show an
abdominal mass, although this test is not very good at detecting colon cancer