Screening & Guidelines
01 What are common screening tests?
Common screening tests for colorectal cancer screening include fecal occult blood test (FOBT), FIT-DNA test (also known as a stool DNA test), sigmoidoscopy, and colonoscopy.
FOBT tests your stool sample and uses a chemical reaction to find traces of blood in stool. A FIT-DNA tests your stool sample for blood and altered DNA in the stool. A positive result on a FOBT or FIT-DNA should lead to colonoscopy. A sigmoidoscopy involves looking into the rectum and lower colon through a flexible tube-shaped instrument that’s fitted with a very small camera on its tip, whereas a colonoscopy uses a similar - but longer - instrument to examine the entire colon. During a colonoscopy, doctors can take samples of the colon (biopsies) and remove polyps.
Newer tests that may help to screen for colorectal cancer include computed tomography, colonography (“virtual colonoscopy”), and stool tests that use DNA-based technology. “Virtual colonoscopy” uses X-rays and computers to produce multiple thin-sliced images of the inside of the colon. It takes about 10 minutes and does not require sedation, but it does require a patient to take laxatives before the test, like regular colonoscopy, and also involves limited radiation exposure. Abnormal results from virtual colonoscopy need to be followed up with regular colonoscopy.
02 What is a colonoscopy?
The colon, or large bowel, is the last portion of your digestive tract, or gastrointestinal tract. The colon is a hollow tube that starts at the end of the small intestine and ends at the rectum and anus. The colon is about 5 feet long; its main function is to store unabsorbed food waste and to absorb water and other bodily fluids before the waste is eliminated as stool.
A colonoscopy allows a doctor to look inside the entire large intestine. The procedure enables the physician to see things such as inflamed tissue, abnormal growths, and ulcers. It is most often used to look for early signs of cancer in the colon and rectum, but it’s also used to look for causes of unexplained changes in bowel habits and to evaluate symptoms like abdominal pain, rectal bleeding, and weight loss.
03 How do you prepare for a colonoscopy?
You will be given instructions from your GI doctor in advance that will explain what you need to do to prepare for your colonoscopy. Your colon must be completely empty for the colonoscopy to be thorough. To prepare for the procedure, make sure you will be near a bathroom. You will be put on a clear liquid diet on the day before your procedure. It may include fat-free bouillon or broth, clear fruit juice, water, plain coffee, plain tea, diet soda, and jello (no red, blue or purple). Some preps may have more restrictions on the days leading up to your colonoscopy. Helpful tips for prep include: chilling the prep fluid, drinking with a straw, using soft toilet paper or moistened wipes, and using hemorrhoid cream prior to starting the prep.
You must also arrange for someone to take you home afterwards, because you will not be allowed to drive after being sedated. Plan to take your test day off from work.
04 What is the recommended age for screening?
If there are no other risk factors such as family history, physicians recommend screening for all adults beginning at the age of 45 (lowered from age of 50).
05 What if there is a family history?
Those with a family history of colorectal cancer are at a higher risk and need to get screened earlier than 45. The risk of developing colorectal cancer increases two to three times when a parent, sibling or child is diagnosed compared to those with no family history. The risk increases three to six times over the general population when a relative is diagnosed at a young age, or there is more than one relative with colorectal cancer. About twenty percent of people who develop colon cancer have other family members who have had the disease. About five percent of patients with colorectal cancer have a well-defined genetic syndrome that causes the disease like Lynch Syndrome or familial adenomatous polyposis (FAP). These conditions are linked with higher risks for colon and other cancers.
06 What if you had previous cancers, ulcerative colitis or Crohn’s disease?
Women with a history of breast, ovarian, or endometrium cancer face an increased risk of developing colorectal cancer, as do people with inflammatory bowel disease, including ulcerative colitis and Crohn’s disease. People who have had colorectal cancer (even if it was completely removed using chemotherapy or radiation treatment) and people who have a history of adenomatous polyps (especially if they were large or if there were many of them) also have an increased risk of incidence.
07 What is the effect of lifestyle?
Several lifestyle-related factors have been linked to increased risk of colorectal cancer. The links between diet, weight, exercise, and colorectal cancer risk are some of the strongest for any type of cancer. Diets that are high in red and processed meats, as well as meats that are cooked at high temperatures, can increase the risk of colorectal cancer. Diets high in fruits and vegetables can decrease the risk. Physical inactivity, obesity, smoking, heavy alcohol use, and Type 2 diabetes all increase an individual’s risk factor.
08 What is the actual colonoscopy procedure?
By identifying and removing polyps, a colonoscopy can dramatically reduce the chances of most cancers from forming in your colon. In many cases, a colonoscopy allows for accurate diagnosis and treatment of colon abnormalities without the need for a major operation.
A colonoscopy usually takes 30 to 60 minutes. You will lie on the examining table on your left side, but you may be asked to change positions at times so that the doctor can better position the scope to examine the different sections of your colon. You will be given pain medication and a moderate sedative to keep you comfortable, and to help you relax during the exam. Most patients do not remember the procedure afterwards. The doctor and a nurse will monitor your vital signs while looking for any signs of discomfort; they will make adjustments as needed.
The doctor will begin by inserting a long, flexible, lighted tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope (koh-LON-oh-skope). The scope transmits an image of the inside of the colon onto a video screen so that the doctor can carefully examine the lining of your colon. The scope is flexible, allowing the doctor to move it through the curves of your colon; it also blows air into your colon to inflate it, giving the doctor a better view.
During the procedure, the doctor can remove most abnormal growths in your colon, like polyps, using tiny tools that are passed through the scope. Most polyps are not cancerous, but they have the potential to eventually turn into cancer. During the procedure, the doctor can also remove tissue samples, which can be tested for diseases of the colon (a biopsy.) The tissue removal and treatments to stop bleeding do not usually cause pain.
It’s possible that you might feel mild cramping during the procedure. This can be reduced by taking several slow, deep breaths. When the doctor has finished, the colonoscope is slowly withdrawn while the lining of your bowel is carefully examined. Bleeding and puncture of the colon are possible, but uncommon, complications of a colonoscopy; in this case, the doctor can pass a laser, heated probe, electrical probe, or special medicines through the scope to stop any bleeding.
The sedative and pain medicine should keep you from feeling much discomfort during the exam, but you may feel some cramping or the sensation of having gas after the procedure is completed. This usually stops within an hour.
On rare occasions, some people experience severe abdominal pain, fever, bloody bowel movements, dizziness, or weakness afterwards. Contact your physician immediately if you have any of these side effects. Be sure to carefully read your discharge instructions and remember that medications such as blood thinners may need to be stopped for a short time after having your colonoscopy, especially if a biopsy was performed or polyps were removed.
Also, please not that you will need to remain at the colonoscopy facility for at least one hour after the procedure so that the sedative can wear off. And because you will be sedated for the procedure, you will need to arrange to have someone else drive you home. Full next-day recovery is normal and expected, at which time you may return to your regular activities.