Colonoscopy: Ask the Expert _ Everything You Want to Know but Are Afraid To Ask
Online Health Chat with Dr. James Church
March 22, 2011
Cleveland_Clinic_Host: Did you know colon cancer is one of the most common types of cancer? If detected early, it's also one of the most curable. A colonoscopy provides the finest in screening because it can both detect and remove polyps before they can turn into colon cancer. Cleveland Clinic colorectal surgeon James Church, MD, will provide answers to your questions about colonoscopy. You will also learn who needs to have a colonoscopy and what the risk factors are for colon cancer.
James M. Church, MD, is a Staff member in the Department of Colorectal Surgery at Cleveland Clinic. He has been Director of the David G. Jagelman Inherited Colon Cancer Registries and Head of the Section of Endoscopy at Cleveland Clinic since 1989. Dr. Church’s specialty interests include all aspects of colorectal cancer and polyps, molecular genetics of colorectal diseases, and functional colorectal and anal problems, including constipation and incontinence, perianal and perineal infections, and inflammatory bowel disease.
He currently is Co-Investigator of the Collaborative Colorectal Cancer Family Registry, funded by a research grant from the National Cancer Institute. He also is Co-Investigator of a study examining the usefulness of CT colonoscopy in detecting colorectal polyps.
Dr. Church has been named to the Good Housekeeping Top Cancer Doctors for Women list (1999), Top Doctors in America (1999-2011), and Who's Who in America (2000-2011).
Dr. Church is actively involved in many scientific and medical societies. He is Past Chair of the Leeds Castle Polyposis Group and the International Collaborative Group on Hereditary Non-Polyposis Colorectal Cancer, and he is the current President of the Collaborative Group of the Americas on Inherited Colorectal Cancer. These international societies are dedicated to the care of patients with inherited colorectal cancer and to research into their disease.
Dr. Church is a Fellow of the American Society of Colon and Rectal Surgeons, American College of Surgeons, Costa Rican Society of Surgery, Royal Australian College of Surgeons, American College of Gastroenterology, American Surgical Association, and the Royal College of Physicians and Surgeons, Glasgow.
A frequent national and international lecturer at scientific meetings, Dr. Church has authored more than 180 articles in peer-reviewed journals and 22 book chapters on hereditary cancers, endoscopy, and molecular genetics of colorectal tumors. He is the author of two medical textbooks and has been Co-Editor of Diseases of the Colon & Rectum since 2000.
Dr. Church received his degree from Auckland University School of Medicine in New Zealand, where he also completed several postgraduate research fellowships. In addition, Dr. Church completed a special fellowship in the Department of Colorectal Surgery at Cleveland Clinic.
To make an appointment with Dr. Church or any of the specialists in the Digestive Disease Institute at Cleveland Clinic, please call 216.444.7000. You can also visit us online at clevelandclinic.org/digestive. To take a free online risk assessment to determine your colon cancer risk and receive personalized screening recommendations, please visit clevelandclinic.org/score.
Cleveland_Clinic_Host: Welcome to our Online Health Chat with Dr. James Church. We are thrilled to have him here today for this chat. Let’s begin with some of your questions.
Lillian: How long does the procedure take? Am I awake for the procedure? What are you looking for? What are the signs of colon cancer? What’s a polyp? Are they dangerous? Are they always removed? There are different types of ‘oscopies,’ total, sigmoid, others. When would one type be advised/used over another? How often should a person get a colonoscopy? What are some of the early warning signs of colon problems? What actually causes colon cancer? Is it just a hereditary risk, poor eating habits, other unhealthy habits (such as smoking or drinking)? Are there any environmental factors (living in industrial areas; living in certain areas of the country)? What are the best foods to eat to lower my risk of colon cancer? Besides foods, is there anything else to lower my risk?
Dr__James_Church: Wow, those are a lot of questions! But they are good questions! I will do my best to answer:
- How long does the procedure take?
Colonoscopy should take about 30 minutes: 12 minutes to get the scope in 5 or 6 feet, and 12 minutes or so to take it out. Then if polyps need to be removed it will take longer, depending on the number and the size of the polyps.
- Am I awake for the procedure?
Different colonoscopists take different approaches to sedation and pain management. My approach is to have patients awake and responsive. They can help me with the colonoscopy by holding their breath or turning from side to side. They get a small dose of a sedative and more, if needed. Most patients do fine with the initial dose, but some need more because their colons are unusually long or twisty. Other colonoscopists just knock patients out. This can be a problem, as patients respond to drugs in different ways, and sometimes they can stop breathing. In addition, recovery is a lot longer. Some patients have a colonoscopy with no medication at all. (I did this twice). In general, the lighter the sedation, the better the colonoscopists technique has to be.
- What are you looking for? What are the signs of colon cancer?
A screening colonoscopy aims either to find asymptomatic cancers at an early stage so they can be cured or to prevent cancer altogether by finding and removing precancerous polyps before they get a chance to turn into cancer. Some colonoscopies are done because of symptoms, rectal bleeding or changes in bowel habits. These are not screening exams but diagnostic exams; and occasionally we will find a cancer or polyps during these colonoscopies.
- What are polyps? Are they dangerous? Are they always removed?
A polyp is a “bump” on the lining of the colon. There are several types, some are precancerous and some are not. However, all colon cancers start off as polyps, so if we can make you free of polyps, you will not get cancer. Therefore all polyps are removed.
- There are different types of ‘oscopies,’ total, sigmoid, others. When would one type be advised/used over another?
You are right. There is colonoscopy (whole colon), sigmoidoscopy (rectum and last 2 feet of colon), proctoscopy (just the rectum), and anoscopy (just the anus). For colorectal cancer screening, total colonoscopy is by far the best. Its downside is the prep and the cost. Flexible sigmoidoscopy is quicker and cheaper, and the patient takes two enemas for prep. However, no sedation is given so it can be painful, and it only checks a limited area of the rectum and lower colon. Therefore, you can have a "normal" flexible sigmoidoscopy and still have a polyp or cancer in the upper colon.
- How often should a person get a colonoscopy?
I assume you mean a screening colonoscopy. It depends on your risk. If you are 50 years or older with no family history or personal history of polyps or cancer, then the first colonoscopy should be at 50. If you are African American, your screening colonoscopy should start at age 45. If that is normal, you should have one every eight years afterward. If you have a close relative with colorectal cancer or polyps, your risk is higher. You should start colonoscopy earlier and do it more frequently, depending on how strong the family history is. For example, the average risk of colorectal cancer in the United States is 6 percent. You have a 6/100 chance of getting it in your lifetime. If you have a parent with colorectal cancer over age 50, your own risk goes from 6 percent to 15 percent. If that parent was younger than 50 when he or she was diagnosed, your own risk is now about 24 percent. If you have two relatives with colorectal cancer, say a parent and an uncle, your risk is now 24 percent. The younger that the relative is affected, the higher your risk and the earlier you should start colonoscopy screening. If you have had colon cancer already, you need a colonoscopy every three years. If you have had precancerous polyps in your colon, you need regular colonoscopies, the frequency of which is determined by the number and size of the polyps.
- What are some of the early warning signs of colon problems?
Rectal bleeding is the most common early warning sign. It is always abnormal and should always be checked. Never just assume it is from "hemorrhoids," even if it isn’t unusual for you. A significant change in bowel habits -- either toward constipation or diarrhea -- is also a concern and needs to be investigated. I don’t mean a temporary change as a result of food poisoning, for example, but a more permanent change that lasts a few days. Abdominal pain can sometimes come from a colorectal cancer, but it has to be fairly advanced. Cancer of the upper colon can present with anemia (low hemoglobin level in the blood), because the blood gets mixed in with the stool and you don't notice it. A patient with unexplained anemia needs a colonoscopy.
- What actually causes colon cancer? Is it just a hereditary risk, poor eating habits, other unhealthy habits (such as smoking or drinking)? Are there any environmental factors (living in industrial areas, living in certain areas of the country)?
Colon and rectal cancer is a genetic disease. It occurs because of a gradual build-up of genetic mutations and other genetic abnormalities in the cells lining the colon. These cells are prone to genetic mutations because of the carcinogens in the stool, and the fact that the stool passes slowly through the colon (average normal transit time is 36 hours). The average colon cancer has mutations in 90 genes, but it takes on average 60 years for these to build up. After 50 years, there are enough mutations to cause a polyp, and then after another 10 years, the extra mutations produce a cancer.
There are several different pathways to colon cancer at a genetic level. The mutations causing polyps and cancer occur mainly because of what we eat and partly from what we inherit in our parent's DNA. Environmental factors encouraging colorectal cancer are red meat and animal fats, char grilling meat, smoking, alcohol, and a high BMI (body mass index), that is, being overweight. Factors protecting against colorectal cancer are a diet high in fresh fruits and vegetables, exercise, and plenty of physical activity. Aspirin can protect against colorectal cancer, as can hormone replacement therapy in women.
- What are the best foods to eat to lower my risk of colon cancer? Besides foods, anything else to lower my risk?
Get regular colon cancer screenings beginning at age 50: if you are African American, your screenings should begin at age 45. Talk to your doctor about earlier screening if you have a personal or family history of colon cancer or polyps
- What are the best foods to eat to lower my risk of colon cancer? Besides foods, anything else to lower my risk?
- A diet high in fat, processed foods and red meats increases colon cancer. Limit your consumption of these foods.
- Eat more fruits and vegetables, whole grain breads and cereals, nuts and beans.
- Being overweight or obese increases your risk of colon cancer. Maintain a normal body mass index (BMI).
- Exercise for at least 30 minutes five days a week.
- Limit alcohol consumption. If you drink, recommended limits are:
- Women: one drink a day
- Men: two drinks a day
- Smoking increases your risk of polyps and colon cancer. Take steps now to quit.
HGR: I am having a colonoscopy in the next few days. My question is: I had bacterial endocarditis in 1979. Is a colonoscopy an invasive procedure whereby I need to take amoxicillin prior to the procedure?
Dr__James_Church: Colonoscopy can potentially cause bacteremia, the presence of bacteria in the bloodstream; however, so can brushing your teeth. I am a little nervous of your history because you may have developed irregularities in your heart valves that would make you at higher than average risk of more endocarditis. Do you have a heart murmur?
In general, we have stopped covering patients who are having colonoscopy with antibiotics. We don't do it for heart murmurs unless there is valve disease or an artificial heart valve. I would suggest you check with your cardiologist. My "fall back" attitude is: if in doubt, give the antibiotic. It is normally given intravenously just before the exam, so get there 30 minutes early.
clara: I am not sure I missed one of the questions I submitted. I had three stents put in seven months ago. I am on Plavix® (clopidogrel bisulfate) and two 81mg aspirins. I have been told to have a colonoscopy now. Should I wait until the year is up?
Dr__James_Church: As long as you are not at high risk for colorectal cancer you can wait a while. If you were my patient, I would do the colonoscopy without stopping the Plavix® or aspirin to see what we find. If we find nothing, or even a couple of tiny harmless polyps, then that is it for now. If we were to find a significant polyp that need to be removed, then the Plavix® and aspirin (because you take two tablets) both need to be stopped for five days before and five days after the exam. I would clear this with your cardiologist to see if he or she thinks you need "bridging" treatment with Lovenox® (enoxaparin).
lena100: Is a person with a factor XI deficiency treated any differently with respect to colonoscopies than other patients?
Dr__James_Church: The whole question of patients with coagulation problems, either "natural" from a factor deficiency or acquired from an anticoagulant such as Coumadin (warfarin) or Plavix®, is a tricky area. The main risk comes when polyps are removed. Therefore a screening colonoscopy could be done without stopping anticoagulation or without factor transfusions. Then, if nothing is found, all is well.
If a polyp is found, then the patient will need another colonoscopy at an appropriate time to treat the polyp; and at this time, be prepared by stopping anticoagulation or having a factor transfusion. This approach minimizes inconvenience and overtreatment but keep patients safe. The second colonoscopy in patients with polyps can be deferred according to the polyp size, thus a small (less than 1cm) polyp would be OK to leave for a year.
Before the Test
lena100: I used a Fleet® enema to prepare for my first and only colonoscopy. My Mom had to drink a thick liquid and got really sick. What is the best and easiest prep for a colonoscopy?
Dr__James_Church: I am afraid there is no alternative to having diarrhea as you flush out all of the stool by drinking a large amount of fluid. The only differences in preparations are the volumes, the timing, and the taste of the fluid. All current preps are designed to cause diarrhea without draining any of your own fluids out of your body. These types of preps avoid dehydration.
Options are GoLytely® (a gallon), HalfLytely® (4 pills and a half gallon), and MoviPrep® (half a gallon). These days, we realize that it is important to do the examination pretty soon after the preparation is done. This has led to a common recommendation to "split" the prep, half the night before and half the next morning. Of course, this can create timing issues as the prep cannot be working when you are driving to the Clinic!
We used to use Fleet® phospho-soda, which was great as it was only two 1½ ounce doses. However it causes problems with the kidneys and so is off the market. Same for the pill preps.
If you take GoLytely® or HalfLytely®, you can add Crystal Light® to give it a taste, just don't add anything with sugar because the colon bacteria can ferment it and produce explosive gas.
Knickers: I had a colonoscopy a few years ago and had a prep that was a little bottle that I mixed with clear soda. My husband just had his colonoscopy, and he had to use the GoLytely® prep. He had a difficult time drinking it all. Couple of questions: Does the prep that I had still exist or is it off the market? If you have to drink the GoLytely® and you are a petite person, do you have to drink it all or can you have a less amount because you are smaller?
Dr__James_Church: As per my answer to a prior question, the "little bottle" (sodium phosphate prep) is off the market. Sorry about that.
Your body size doesn't really make your colon easier to clean. You would be surprised how long and twisty some petite people’s colons are -- and full of stool. No, take the prep as prescribed, at least the first time. Of course, if the stool is coming out clear, there is no point drinking any more (unless it is a split prep, and you need the other half in the morning.)
gwg: I am having this procedure done on Monday, and I was wondering if they will put me under with an anesthetic, or is the patient awake? Thanks for your time, it is greatly appreciated.
Dr__James_Church: You are welcome. As I mentioned earlier, the amount of sedation given varies according to the wishes of the patient, the skill of the endoscopist, and the difficulty of the examination. While some patients prefer to be put completely to sleep, others like to be completely awake with no sedation at all. That has the advantage of avoiding the need for a driver and allowing you to do some work after the exam (if anyone would ever want to).
My own practice is to start with a small dose of Versed (midazolam), a sedative like Valium (diazepam), and to give more if necessary. Usually, no more is needed. The patients are relaxed, comfortable, can watch the exam if they want, and can listen to music or chat with the nurses. If a patient has severe pain, then of course we give as much as we can safely give. Pain is actually a warning sign to the colonoscopist to stop pushing, so it is useful to have the patients able to respond. Good luck with your exam.
adamsd2: My mother-in-law was given tablets to take instead of the liquid prep. She was in Virginia. Is there such a thing here, in Cleveland?
Dr__James_Church: The sodium phosphate tablets are no longer on the market here. I guess it is possible that some drug stores still have them, but they are off the market for a reason. The kidney damage can lead to a need for transplant.
Sometimes Dulcolax® (bisacodyl) tablets are given with a liquid prep. This is part of the HalfLytely® prep. Usually not Dulcolax® by itself though.
After the Test
Jamie: After a colonoscopy, are there any restrictions initially about eating, driving, returning to work etc.?
Dr__James_Church: Your ability to work is determined by the sedation and pain relief you have had. We discourage patients from driving for at least eight hours after getting any sedative or narcotic. If you need or want to work, see about a colonoscopy without sedation.
Eating and drinking should be fine immediately.
After the exam, you will be left with some air in your colon. Good colonoscopists can minimize this, but less skilled colonoscopists sometimes leave the patient blown up like a balloon. It generally takes 10 to 30 minutes to pass this gas. Then you are good to go. If you start again with the food, remember your colon is empty and needs to fill up before you have a bowel movement. This may take one to two to sometimes three days depending on how much roughage you eat.
clara: What types of polyps are always cancerous? How often should they be checked?
Dr__James_Church: There are two main types of polyps that are precancerous: adenomas and serrated polyps. However, only about 1 in 100 adenomas will ever become cancer. The bigger they are (which means the longer they have been there), the more likely they are to be on their way to cancer. As polyps get closer to cancer, their cells start to look wilder and wilder. This is called dysplasia. Polyps with severe dysplasia are very close to cancer. We pay very close attention to them. I hope that this answers your question. Remember, that although only 1 in 100 polyps will turn into cancer, every cancer starts off as a polyp.
magr: I recently had a colonoscopy in which my biopsy results showed no cancer; only tubercles were found. The doctor who performed the test wants me to have another scope in three months to make sure he didn't miss anything. What is the normal protocol for frequency since my only risk factor is being overweight? From the research I did, my initial colonoscopy did not increase my risk level, since tubercles were the only thing found, which appear to have no risk of becoming cancerous the way polyps can, which I did not have.
Dr__James_Church: I am not sure what you mean by "tubercles." If you mean tubular adenomas, then these are pre-cancer polyps. The normal time to do a follow-up colonoscopy depends on several things. The first thing to think of is the likelihood of the colonoscopist missing a polyp. This likelihood is higher if the colon is not well-prepared or if it is particularly twisty and difficult to examine. Often, a poor preparation and twistiness go together. The second factor is the "proneness" of the colon to produce polyps. We estimate this by the family history (zero in your case) and the number and type of polyps found. If a patient has three precancerous polyps in a well-inspected colon, we recommend follow-up in three years. One precancerous polyp in a well-inspected colon means follow-up in five years.
The "aggressiveness" of the polyp -- that is, how close it is to becoming cancer -- also counts. One "aggressive" polyp should be followed in six months to make sure it is all gone, and then a year later to make sure it has not come back.
Finally, the size of the polyp is important. Very big polyps are difficult to remove cleanly, especially if they don't have a stalk. Therefore, the check in three to six months to make sure they are gone is necessary.
Still the Best
Peppy: Could you please explain the "swallowing the camera" colonoscopy? Is there a great deal of radiation exposure?
Dr__James_Church: The pill camera colonoscopy is not ready for general use yet; it is still a research test. The pill camera test for the small intestine is in use, however, and is a valuable addition to our options for checking the small intestine. The reasons it works better in the small bowel than the colon are that: (1) it only takes two to three hours to get through the small bowel, but can take up to 36 hours to get through the colon; (2) the small bowel is easy to get clean but the colon is not easy to keep clean; (3) the colon is a much wider organ than the small bowel, with many more nooks and crannies.
The other reason why camera colonoscopy is not as good as regular colonoscopy is the same as for virtual colonoscopy. If you see something, you cannot treat it or even biopsy it. You need a regular colonoscopy, as well. However, I see a role for pill camera colonoscopy in screening out patients with normal colons, so that we only colonoscope patients who we know have polyps. It will be a couple of years at least before the pill camera colonoscopy enters regular use.
reidj2: Does the Cleveland Clinic use the capsule colonoscopy?
Dr__James_Church: Not yet. We do small bowel capsule routinely.
KGal: I had a barium study 10 years ago with a sigmoid and all was good. I am 62 and they want me to have the colonoscopy. However, the anesthetics used give me terrible migraines that last for days. The last one I had for a procedure lasted three weeks and ended in a mild heart attack. I want to have my colon checked, but taking the chance of problems again doesn't seem worth it. Is there another way without a lot of radiation like the virtual? I read in Europe they are doing the sigmoid with the occult blood tests and having wonderful success in prevention and early diagnosis of problems. Thank you.
Dr__James_Church: The best option for screening the colon for polyps and preventing cancer is a colonoscopy. This is because colonoscopy is the most accurate option and the only one that allows removal of the precancerous polyps. Having said that, colonoscopy can be difficult in some people for a variety of reasons.
Virtual colonoscopy, where you would have a CT scan and the radiologist would examine a reconstructed 3D image of the colon, is accurate but does not allow polyp removal. If something is found, you would need a regular colonoscopy as well.
Not all colonoscopists use the same types of sedation. I suspect your troubles come from the use of a narcotic such as Demerol (meperidine) or fentanyl. I usually just give a smallish dose of Versed, a sedative similar to Valium. This is very well-tolerated by most people and is sufficient for most examinations.
The technique of the colonoscopist makes a big difference. If technique is not good, patients need more sedation. Good technique minimizes the need for pain relief and sedation. I would suggest you find a colonoscopist with an excellent reputation who uses light doses of sedation.
For you, I would need to know what a "tubercle" is and why your doctor was so unsure of whether anything had been missed.
lena100: If a person with well-controlled celiac disease had a colonoscopy at 50 with completely normal results, when should the next colonoscopy be (no immediate family members with colon cancer but maternal uncle had it)?
Dr__James_Church: Celiac disease doesn't affect risk of colorectal cancer, although some of the symptoms can mimic symptoms caused by colorectal cancer. Therefore, the interval to the next colonoscopy from a baseline screening examination in a patient at average risk can be eight years. I say eight instead of 10 because the approximate interval from the appearance of a precancerous polyp to a cancer is 10 years. Therefore there is little sense in waiting 10 years.
gwg: I recently had an ileocolic resection due to Crohn's disease, will it be possible to see through a colonoscopy if the Crohn's has come back?
Dr__James_Church: Yes. In fact colonoscopy is the best way to check for recurrent Crohn's. Crohn's likes to come back just upstream of an anastomosis, so it’s a likely spot. However, studies have shown that when patients with an ileocolic anastomosis for Crohn's disease are scoped one year after the surgery, 75 percent will have some ulcers in the area.
This doesn't necessarily mean that the Crohn's is back or that it needs to be treated. Sometimes we have to be a little careful not to over-react to some ulcers at the anastomosis. If you are having symptoms, however, the colonoscopy allows the anastomosis to be checked and potentially the small intestine for a foot or so upstream of the anastomosis.
Peppy: Would aspirin therapy (81mg) and a stent be treated with the same precautions as Plavix® or other anticoagulants?
Dr__James_Church: I generally don't worry about 81mg aspirin. I am happy to take polyps off without stopping that. Not so for Plavix®. The presence of a stent per se is not a problem either.
lena100: Do you recommend that normal patients get a fecal occult test annually in addition to colonoscopies at appropriate intervals?
Dr__James_Church: No. It doesn't make sense to me. Sometimes patients do this and get a positive Hemoccult® because of hemorrhoids or eating rare steak. Then they need another colonoscopy to make sure that there is not a missed cancer. Of course there is always the possibility that colonoscopy will miss something serious, but this possibility is low and doesn't justify everyone getting Hemoccults as well.
Cleveland_Clinic_Host: I'm sorry to say that our time with Dr. James Church is now over. Thank you again Dr. Church for taking the time to answer our questions about colonoscopies.
lena100: Thank you for such an informative chat.
Dr__James_Church: You are welcome.
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