Colon cancer is the second leading cause of cancer-related deaths in the United States. One of the best ways to check for colorectal cancer is with a colonoscopy. (1)
Detecting it early can help reduce the risks. In fact, deaths from colorectal cancer (cancer in the final part of the large intestine or rectum) decreased by 2.2% per year between 2007 and 2016 because of improved care and screening. (2)
A colonoscopy is not risk-free, however. Complications can arise during this procedure. So what are the benefits versus the risks? And are there ways to reduce your risk for colon cancer?
What Is a Colonoscopy?
A colonoscopy is a medical procedure where a doctor sends a tiny camera up inside your colon to get an up-close look at the bowel wall.
Here’s a closer look at what happens during a colonoscopy.
Colonoscopy Prep and Procedure
To have a successful colonoscopy, your large intestine will need to be “cleaned out.” Your doctor will put you on a special diet of liquid foods such as broth a few days before the test. You’ll also need to avoid red and purple juices.
Your doctor will also give you medications or laxatives to help clear out as much stool as possible. You’ll want to stay close to home for this part since the laxatives will cause diarrhea. It sounds uncomfortable, but this will give your doctor the best possible view of your colon. (3)
The day of the test the doctor will use a special instrument with a camera and light called a colonoscope. It will go up the anus and travel along the colon, capturing a close look at the health of the intestinal wall on video. You are typically under anesthetic and go home the same day.
The doctor will use air or carbon dioxide to expand the colon. This helps to open up the area to get the best view of your colon. The procedure takes around 30 to 60 minutes, plus the time it takes for you to wake up from the anesthetic. (3)
Why They’re Performed
The main reason your doctor may want you to get a colonoscopy is to check for signs of colorectal cancer. But your doctor may use a colonoscopy to discover the reason behind other issues.
If you have blood in your poop, gut pain, or a sudden change in bowel habits, your doctor may want to take a look to see why. They may also want to check your colon if they suspect you have an inflammatory bowel disease (IBD), such as ulcerative colitis, or even an intestinal blockage. (3, 8)
You are considered at average risk for colon cancer if there isn’t a family history of the disease. If you are in this category, medical professionals recommend a colonoscopy every 10 years after the age of 50, until the age of 75. After that, doctors will make recommendations for each person individually. (4)
A medical professional may encourage screening earlier than 50 or more often than every 10 years if: (5)
- You have family members who have had colorectal cancer
You have a genetic condition, such as familial adenomatous polyposis (FAP) or Lynch syndrome, which are hereditary diseases where you develop benign growths (polyps) more readily. (6, 7)
- You have received an IBD diagnosis
In these cases, doctors may suggest having a colonoscopy every five years. (4)
Modern medicine sees colonoscopy as the “gold standard” for detecting and lowering the risk of developing colorectal cancer. In the last few decades, colonoscopies in the over 50 age group have gone up by 21%. That same time and age group saw a drop in colon cancer rate of 32%. (1)
What Can a Colonoscopy Uncover?
You may be wondering what exactly a doctor searches for when exploring through your colon.
He or she is inspecting your bowel wall for anything out of the ordinary. But when it comes to colon cancer screening, your doctor is looking for strange growths called polyps.
What Are Colon Polyps?
Polyps are bumps of tissue protruding from the wall of your intestine. They can be somewhat flat against it. Or they can have a stalk and be hanging off the inside of your colon. (9)
There are three main types of polyps: (9, 10, 11)
Adenomatous or neoplastic—These are small benign (non-cancerous) tumors that come from mucus-producing cells lining the colon wall. Studies suggest that they occur in 34.3% of people without any symptoms. This type can turn cancerous over time.
Hyperplastic—This type occurs from colon irritation or when the colon is trying to repair itself from a trauma. Usually they are small. They are the most common and are less likely to develop into cancer.
Serrated—Named for their jagged edge appearance, serrated polyps lead to one-fifth of colorectal cancers. Studies suggest that 15.6% of people may have this kind.
Is It Necessary to Remove Polyps?
Polyps are odd in that they can grow larger, stay the same, or even shrink. What they are going to become isn’t always easy for your doctor to predict. There is no “sure way” to say what polyps will become cancerous and which ones will not. Although the larger a polyp, the higher the risk.
But one thing researchers do know is that all colon cancers start as a polyp. Because of this, it may be best to adopt a “better safe than sorry” approach—remove anything that has the potential to turn cancerous. (12)
This strategy is why colorectal cancer deaths are decreasing. Studies suggest that screening reduces the chance of death from colon cancer by 65% and polyp removal decreases it by 53%. (13, 14)
Stats are pretty clear that the number and size of polyps correlate to your chances of developing colorectal cancer. Your risk jumps two to fivefold, so you want to take care of them sooner than later. (15)
This “up-close” look at your intestines may reveal other conditions as well.
For example, your doctor could find diverticulosis. A normal bowel is essentially a long tube. You can develop small pouches along the tube called diverticulosis. If those pockets become inflamed and cause symptoms, it turns into diverticulitis.
Acute flare-ups of diverticulitis are related to colon cancer, so your doctor may want to perform a colonoscopy more frequently to monitor your health. (16)
A colonoscopy may also reveal melanosis coli. This is when the lining of the colon turns brown, sometimes even black. Although there is no known cause, some doctors connect it to laxative use. Most researchers think this condition is harmless and unrelated to colorectal cancer. (17, 18, 19)
Risks Associated with Colonoscopies
As valuable as a colonoscopy is in detecting polyps and other issues with the large intestine, they are not a “perfect” system for catching colorectal cancer. Studies suggest that a colonoscopy may still miss up to 6% of colon cancers. (20)
A colonoscopy is also not completely risk-free. Serious complications develop in 0.28% of people who get a colonoscopy.
Overall, when it comes to colonoscopy complications, 85% are related to polyps removal. Here’s the major risks associated with colonoscopies: (20)
Cardiopulmonary complications—Your risk for angina (chest pain from decreased blood flow), heart attack, or stroke goes up slightly by 0.14% for 30 days after a colonoscopy. This may be due to the anesthetic.
Gas explosion—It is extremely uncommon, but your own gas can explode in your abdomen during a colonoscopy. The electrical equipment ignites the hydrogen and methane. One case resulted in death. But again, this is rare. Medical professionals think that it’s related to indigestible sweeteners, such as lactulose, mannatoil, and sorbitol.
Increased bleeding—Removing polyps raises your risk of bleeding by 7 times. Associated with this, hemorrhages from removing polyps occurs 0.1%–0.6% of the time. Risk factors include size and amount of polyps.
Perforated bowel—With polyps removal, the chances of a perforated large intestine increases by 7 times. This is when a hole is accidentally poked in your intestinal wall by the surgical equipment. Although this rarely happens (between 0.1% and 0.3% of colonoscopies), it is a major complication that needs surgery and could lead to an infection.
Postpolypectomy coagulation syndrome—Another serious complication is postpolypectomy coagulation syndrome, meaning the heat from the instruments created a burn on the inside of your colon. This happens in 0.1% of people who undergo a colonoscopy.
Transient bacteremia—Transient bacteremia (increased bacteria in the bloodstream for a short period of time) happens in approximately 4% of procedures, but the range can reach up to 25%. It’s usually from defective equipment or equipment not properly cleaned from the previous colonoscopy.
One immediate effect is that you could feel nauseous because of the anesthetic. But the most common symptom people have after a colonoscopy is bloating. Around 25% of people experience this. Approximately 5–11% have abdominal pain and discomfort. Doctors think this is from inflating the bowel with air so that they can get a better look during the procedure. (20)
People report having these concerns for a week or two following the test. After 30 days, few people were still experiencing bloating and/or discomfort. (21)
Ways to Lessen Risks During Colon Cancer Screening
Any procedure has a small amount of risk involved. Yet, you may want to undergo a colonoscopy to reduce your chances of colorectal cancer, which could be riskier in the long run.
Fortunately, there are ways you can reduce your chances of having issues from a colonoscopy.
Do Your Homework
Here’s steps you can take to help your colonoscopy go more smoothly:
Ask questions—Ask potential doctors how many colonoscopies they perform per year and how many years they’ve been doing colonoscopy. Also, ask how many serious complications have developed with people that were under their care. These are fair questions that you should receive honest answers for.
- Avoid pain medications—Drugs, such as non-steroidal anti-inflammatories (NSAIDs) and aspirin, thin the blood and may increase the risk of delayed bleeding. Try and avoid these for several days before and after your test. (22)
Clean out your colon—Making sure that your colon is as clean as possible is essential. Having stool still in the colon prevents them from thoroughly checking for polyps. Your doctor may even make you reprep and come back on a different day if your colon isn’t clean enough. It also increases the risk of bleeding if you have polyps removed. (22)
Choose sedation—Being awake may allow you to move around too much during the procedure. That increases your chances of a perforated large intestine. So opt to go under for the test, which medical professionals generally recommend anyways. (22)
Select your doctor wisely—A doctor’s performance can vary greatly. Usually a gastroenterologist performs the procedure, but not always. In the United States, 60% of all colonoscopy centers don’t have a minimum amount of procedures to complete before being allowed to practice. (23)
Other Ways to Screen for Colon Cancer
If you are at lower risk for colorectal cancer, new tests are emerging that could help you either avoid a colonoscopy or possibly get them less often. These new methods using stool samples and blood tests show promise, but aren’t as accurate as actually seeing the inside of the colon.
One test is a guaiac-based fecal occult blood test (gFOBT). For this, the doctor gives you a stool collection kit to use at home. Then lab techs check for hidden blood in the stools. A 10-year study using this screening method every 2 years reduced colon cancer deaths by 18%. Another 30-year study showed this screening reduced deaths by 32%.
The drawback is that this test is only 50% accurate, and that’s not precise enough when it comes to your health. Blood from red meat, enzymes in plants, and supplements like vitamin C could skew the results. (24)
Fecal immunochemical test, or FIT, is similar to the gFOBT. It checks your stools for blood that could be coming from polyps. An 11-year study suggests that it may reduce colon cancer deaths by 22%. This test isn’t as effective at detecting small polyps, however. Its accuracy varies depending on how the labs apply the results, so this one still needs to be perfected. (24)
Methylated SEPT9 screening
A methylated SEPT9 test searches for specific proteins in the blood that may belong to dividing carcinogenic cells. This test looked promising at first. But further study suggests that it isn’t as accurate as researchers were hoping. It is especially inaccurate at detecting advanced cancers. (24)
Stool DNA screening
Stool DNA tests look for cancerous cells that your intestines could be shedding into your poop. It is more costly and less effective than a FIT test, so you may not want to opt for this one. (24)
Virtual colonoscopy screening
A “virtual” colonoscopy, or computed tomography colonography (CTC), is another newer test. It requires you to clean out your colon in the same way you would for a traditional colonoscopy. Instead of an internal camera, you take a special contrast dye that radiographic imaging will pick up.
The jury is still out on how well this procedure works for prevention. The other serious disadvantages are you could be allergic to the contrast and also get exposed to radiation. Plus, you’ll need a traditional colonoscopy anyways to remove polyps if they’re found. (24)
Lifestyle Choices and Reducing Colon Cancer Risk
More important than getting a colonoscopy is making lifestyle choices that promote health. This lowers your chance for disease overall.
As mentioned earlier, some genetic factors may increase your chances of developing colorectal cancer. But this is a small fraction of the population, around 2–5%. Your risk also goes up as you age, and if you have an IBD. (25, 26)
Those factors may be out of your hands, but there are several things you can control to reduce your likelihood of colorectal cancer.
Studies suggest that your diet choices matter. In fact, researchers estimate that up to 40% of all cancers could be connected to poor dietary habits. So invest in your health by making great food choices. (27)
Load up on fruits and vegetables. These typically colorful foods are rich in phytochemicals that could have a protective effect against cancer. Green fruits and vegetables may offer the most protection. (28)
Fiber content from fruits and vegetables gives you a cancer-protective effect too. Eating more than 20 grams of fiber per day may reduce your risk of colon issues by 25%. Fiber helps prevent constipation and could reduce your colon cells’ exposure to cancer-causing toxins in your stools. (29, 30)
Plus, fruits and vegetables are good sources of minerals and vitamins that could aid in prevention. For example, research associates the B vitamin folate with a decreased chance of colon cancer. (Hint: Green leafy vegetables are excellent sources.) (31)
Red and processed meats increase your chances of colorectal cancer in a dose dependant-manner—the more you eat, the higher your chances. So try and opt for other protein sources as much as possible. (30)
Overall, quitting smoking might be the single best lifestyle choice you can make to reduce your chance of colon issues. There is no “safe” amount of tobacco. Tobacco use of any kind increases your chance of most cancers, colorectal included. Studies show that smoking can increase your risk of colorectal cancer by 18%. (27, 31)
You may also want to consider whether alcohol should be a part of your lifestyle. Studies suggest that even small amounts, less than one drink a day, can raise your risk. Avoidance is best, as alcohol blocks your body’s ability to take in folate. (32)
Another huge risk factor is weight. Obesity may increase your chances of colorectal cancer by 19%. What goes hand in hand with obesity is a lack of physical activity. Regular activity may lower the risk of colorectal cancer by 24%. So choose an activity you enjoy, and you’ll be taking care of both factors at the same time. (30)
Some supplements may enhance your efforts to support colon health, such as:
Fulvic acid—Carbon-based binders can be an excellent tool in helping support colon health. They contain extracts of fulvic acid. Studies suggest that fulvic acid acts as an anti-inflammatory. It may also help prevent malignant cells from “sticking together” and inhibit them from latching onto your colon wall. (33)
Intestinal-moving herbs—Constipation may increase your risk, so get your colon moving. Aim to have two to three bowel movements a day to make sure toxins properly exit your body. Intestinal-moving herbs—such as clove, ginger, and wormwood—may help prevent you from getting backed up. (34)
TUDCA—TUDCA is a bile acid that supports detoxification and helps protect your liver. It also may inhibit malignant cells from growing. Animal studies suggest that TUDCA significantly suppresses malignant cells from multiplying. (35)
Vitamin D—Studies suggest that higher vitamin D levels are linked with lower rates of developing polyps. Vitamin D may keep malignant cells from replicating. Check your vitamin D levels by asking your medical practitioner for a simple blood test. Optimal levels are 75–100 nmol/L. (27, 36)
You Are in Control
Colon cancer is a serious concern. A colonoscopy may be the best type of test to monitor the health of your colon at the moment.
But they do come with risks. You may experience temporary bloating and nausea for a period of time following your surgery. Major risks happen much less frequently but include complications like internal bleeding and perforated bowels.
If you do choose to have a colonoscopy, remember that you are in control. Do your homework. You decide who will perform the procedure. Ask questions and be as informed as possible.
You are also in control of many risk factors that contribute to colon cancer. Avoiding alcohol and tobacco, making good food choices, and regular physical activity are all positive steps you can take.
Supplements, such as carbon-based binders and TUDCA, are also important preventative tools. They can support healthy detox organs and regular elimination.
Your colon health is more in your hands than you think. What new lifestyle choices are you going to make to boost your colon health?