Diagnosis – How do we Diagnose Colorectal Cancer?
How did Sandra get diagnosed with Colorectal Cancer? As you may remember from the last blog, Colon cancer was initially suspected when she went into the ER with complaints of rectal bleeding. Her CT scan showed a lemon-sized mass in her colon which was suspicious for either infection or tumor. The doctors were not sure if the mass represented an infection of the colon, known as diverticulitis, or a more worrisome condition (colon cancer). Initially Sandra was given intravenous antibiotics for 3 days and then sent home with follow-up with a gastroenterologist for a colonoscopy.
On her colonoscopy, the mass was visualized and biopsied. This biopsy was then sent to the pathologist who looked at the specimen under the microscope and determined it to be consistent with adenocarcinoma of the colon (the most common type of colon cancer).
What other options could Sandra have taken?
Sandra actually presented with symptoms so the best test for her was colonoscopy. If she hadn’t been experiencing any symptoms and was going for a screening test, other options would have been available to her.
The most common screening method for colon cancer is colonoscopy. This is usually done as a screening test before any symptoms like rectal bleeding have occurred. If symptoms are already present (thus not a screening but rather a diagnostic test), colonoscopy is usually recommended because the colon can be visualized and biopsy taken at same time.
The best screening test for you will be determined by you and your doctor. Usually screening begins at age 50. Certain factors will be taken into account including:
- Your age
- Your medical history
- Your family history
- The potentials harms of each test
- The preparation needed for each test (possible colon cleanse using tablets and/or drinking special liquid to empty your bowel).
- Possible sedation (light anesthesia) to perform procedure and see you are healthy enough for this.
- Convenience of test and sensitivity ( Likelihood to predict colon cancer)
- Cost and insurance coverage.
After reviewing multiple colon cancer sites, I chose the following list of screening tests from the National Cancer Institute (https://www.cancer.gov/types/colorectal/screening-fact-sheet) highlighting the pros and cons of each.
SCREENING TESTS FOR COLORECTAL CANCER
Fecal Occult Blood Test (guaiac FOBT or fecal immunochemical test [FIT])
Advantages:
- No cleansing of the colon is necessary.
- No dietary restrictions are needed before FIT.
- Samples can be collected at home.
- Cost is low compared with other colorectal cancer screening tests.
- There is no risk of damage to the lining of the colon.
- No sedation is needed.
Disdvantages:
- The test does not detect some polyps and cancers.
- False-positive test results are possible (that is, the test may suggest an abnormality when none is present).
- Dietary restrictions are needed before guaiac FOBT.
- Additional procedures, such as colonoscopy, may be needed if the test result shows blood in the stool.
Stool DNA Test (FIT-DNA)
Advantages:
- No cleansing of the colon is necessary.
- No dietary restrictions are needed before the test.
- Samples can be collected at home.
- There is no risk of damage to the lining of the colon.
- No sedation is needed.
Disdvantages:
- Cost may be higher than that of gFOBT or FIT.
- Test sensitivity for adenomas is low. (finding a cancer when there is one)
- False-positive test results are possible (that is, the test may suggest an abnormality when none is present).
- Additional procedures, such as colonoscopy, may be needed if the test result is positive for blood or abnormal DNA.
Sigmoidoscopy
Advantages:
- For most patients, discomfort is minimal, and complications are rare.
- The doctor can perform a biopsy or polypectomy (removal of a polyp or adenoma) during the test, if necessary.
- Less extensive cleansing of the colon is necessary for this test than for a colonoscopy.
- Sedation is often not required.
Disdvantages:
- Abnormal growths in the upper part of the colon will be missed because the test allows the doctor to view only the rectumand the lower part of the colon.
- Bowel cleansing is needed before the test.
- Medication and diet changes may be needed before the test.
- There is a very small risk of bleeding or of tearing or perforation of the lining of the colon.
- Additional procedures, such as colonoscopy, may be needed if the test finds an abnormality.
- The availability of sigmoidoscopy has decreased substantially in the United States in recent years.
Standard Colonoscopy
Advantages:
- This test is one of the most sensitive currently available.
- It allows the doctor to view the rectum and the entire colon.
- The doctor can perform a biopsy or polypectomy during the test if necessary.
Disdvantages:
- Even though this test is highly sensitive, it still may not detect all small polyps, flat or depressed (nonpolypoid) lesions, or cancers.
- A thorough cleansing of the colon is required before the test.
- Diet changes are needed before the test, and medications may need to be adjusted.
- Some form of sedation is almost always used. As a result, the patient must have someone accompany them to the procedure and drive them home afterward, and they may not be able to work the day of the procedure.
- There is a small risk of bleeding or of tearing or perforation of the lining of the colon; this risk increases with age, with the presence of other health problems, and when polyps are removed.
Virtual Colonoscopy
Advantages:
- With this minimally invasive procedure there is little risk of damage to the lining of the colon.
- No sedation is needed.
Disdvantages:
- A thorough cleansing of the colon is required before the test.
- Can miss small polyps.
- Additional procedures, such as colonoscopy, may be needed if the test finds an abnormality.
- Patient is exposed to small amounts of ionizing radiation.
- Not covered by all health insurance plans or Medicare.
- Can unintentionally discover medical results outside the colon that may trigger unnecessary procedures or follow-up.
Another test that was not mentioned on this site, but is now available is the Cologuard test.
The Cologuard test : approved by the FDA in 2014 and tests for specific DNA markers for colon cancer as well as blood.
Advantages:
- At home test – a kit is sent to your house
- Do-it-yourself- results return within 2 weeks of sending kit off
- No sedation or preparation needed.
- More accurate than FOBT or FIT tests.
Disdvantages:
- Can give incorrect results – may give more false positive results (results saying you are at risk and possibly have genetic markers) or false negative (saying you don’t have a potential problem when you actually do).
- May not be covered by your insurance.
As you can see, there are many screening tests. Colonoscopy remains the “gold standard”.
The best screening test for you will be determined by you and your doctor. By undergoing screening, the likelihood of finding colon cancer at a very early stage is very high. This means a much better prognosis than if discovered after you have already experienced symptoms.
So don’t wait – talk with your doctor to see when and which test is best for you!
In health and happiness,
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This post first appeared on Encinitas OBGYN Gynecologists | HRT | Menopause |, please read the originial post: here
