Can a doctor tell if you have colon cancer by taking test?

Depends on type. Guaiac for blood in the stool can be a sign of colon cancer. Colonoscopy is a screening study, where a polyp, tumor, or mass can be biopsied and a diagnosis given by a pathologist for colon cancer. Imaging studies may suggest a tumor also. There are many ways of screening for colon cancer (usually started after 50 years), depending on age and symptoms.
Colonoscopy. The best test to find colon cancer is colonoscopy, which is a fiber optic camera evaluation of the colon. Blood tests such as cea levels are not used to screen (i.e. Check) for colon cancer in asymptomatic patients.
A biopsy. A colonoscopy is the best way to screen for colon cancer. If there is anything suspicious seen on the colonopscopy, the doctor can take an immediate biopsy. The biopsy is sent to a pathologist who reviews the specimen and gives the diagnosis of colon cancer if it's there.

Related Questions

What to do if I might have colon cancer im afraid/embarrassed to tell my doc?

Don't be. You should not be afraid or embarrased to tell your doctor anything, especially if it is something that concerns you. If your relationship with you doctor is awkward, i would get a new primary care physician until you find one that you are comfortable with. Read more...

Why are most doctors so quick to write off colon cancer probability in a 21 year old? Most doctors wont test me for colon cancer why?

Signs & symptoms . Signs & symptoms drive medical decision making. This means knowledge of natural history of diseases & how disease effects a pt (pathology). If you have signs & symp of colon cancer, then your doctor will investigate that possibility. Just cause you think you have something doesn't mean you have it. Why are you so adamant about colon cancer? Tests for colon cancer are invasive & carry risks. Read more...
Too young. Unless you have bad genetic mutation and/or terrible luck, colon cancer is exceeding rare for a 21 year old. Screening colonoscopy has an unacceptable complication vs benefit ratio when performed on an asymptomatic, normal risk young person. Read more...

What can a doctor's rectal exam tell me about my risk for colon cancer?

Depends. A digital rectal exam can reduce the likelihood of a cancer near the anus, and can detect if you have blood in your stool. If either demonstrates an abnormality, then you need a colonoscopy to evaluate the rest of your colon. Read more...
Screening tool. On rare occasion a low lying rectal cancer can be detected on the exam by feeling it. Most often stool is sampled and analyzed for traces of blood. If blood is found then the doctor can check for hemorrhoids and may recommend a colonoscopy to find out if there is a specific cause such as a polyp or a cancer or diverticulosis. Read more...

Doctors can you tell me when should I be tested for colon cancer?

50 if no symptoms. The current recommendations are to get a screening colonoscopy at age 50 if no symptoms and no family history. Certainly sooner if you are having GI problems. Also sooner if family history. For example if parent had colon cancer at 50 you should be screened 10 years earlier at 40. Read more...

Can doctors tell me what does one do to lessen the chances of getting colon cancer?

Colonoscopy. Kduffey1. Colon cancer is the only cancer that can be prevented. Colon cancer appears more from 50 years up. Persons with familiar polyposis will develop colon cancer, colon cancer comes from a previous benign polyp, if a person has colonoscopy from 50 years up will not develop colon cancer. Colonoscopy should be done earlier if the person has rectal bleeding or diarrheas or constipation. Read more...

28 yo. Colon cancer fear. No family hist. Ibs diagnosis. Have had tiny specks of blood on tp. Doc said hemmroids. Negative occult test. Do you agree?

Yes. At your young age with no family hx of colon cancer, it would be highly unlikely that your sx represent colon cancer. Bright red blood specks on toilet paper suggest lower rectal bleeding (not within stool, thus negative hemoccult test) & is much more likely hemorrhoidal in nature. Read more...
Too young for it! Colon care is uncommon under the age of 50 years, so you should not live under this fear when you are so young. The fact that your doctor has checked you and found hemorrhoids as the cause of your questionable bleeding. Once you get to the age of 45-50 years. screening with Colonoscopy would be the best security to avoid any fear of this Cancer which is easily detectable and preventable. Read more...