Why a Routine Colonoscopy Is More Essential Than Ever

Colorectal (colon and rectum) cancer is the third most commonly diagnosed cancer in American men and women. The best way to prevent the disease, says Santa Monica-based gastroenterologist Dr. S. Radi Shamsi, is to have regular colonoscopies after a certain age. The procedure can detect abnormal types of tissue, including small growths called polyps that form on the lining of the colon (the last segment of our digestive tract) that–if left unchecked–can develop into cancer. Currently, the recommended age to begin regular testing is fifty (or earlier, depending on one’s health and family history), but this might change due to recent findings by the American Cancer Association signifying an increase in colorectal cancer in young and middle-aged American adults. A colonoscopy can also detect other ailments in the gut, like diverticulitis or colitis.

Unfortunately, there is colonoscopy aversion, as the prep alone can cause major anxiety. “Most people come into my office with apprehension,” Shamsi says. “Colonoscopies are one of the easiest, safest, most fruitful preventative procedures modern medicine has to offer and to avoid them is a mistake.” Here, he explains the nuts and bolts.

A Q&A with Dr. S. Radi Shamsi


Can you explain how a colonoscopy typically unfolds?


The doctor controls a small tube with a light and camera that shows the patient’s colon lining on a screen. A tube is gently inserted in the rectum, and then we advance the scope through the entire large intestine, and get to the appendix, as well as a short distance of the small intestine (about two and a half feet deep). The patient is mildly sedated and comfortable for the entire procedure. The goal is to look for any abnormalities and remove them. Removal techniques could include forceps that bite polyps off, snares that lasso and burn off larger polyps with electrocautery, or gas lasers that decimate any growth and do away with abnormal cells. We can inject ink to mark an area of abnormality to make it easier to find on future procedures. We also inject air to expand the colon so we can see more clearly. In my surgical center, we use carbon dioxide, which provides the patient significant comfort in the post-procedure setting, since it is a thousand times more rapidly absorbed than air, so patients wake up on recovery without any post-procedure bloating.


When is it appropriate to get a colonoscopy before the age of fifty? Are there specific indicators?


If one has a family history of colon cancer in a first-degree relative (mother, father, brother, sister), or a family history of adenomas or polyps in a family member before sixty, they should start screening at forty (or ten years younger than the family member at the time of diagnosis), and repeat every five years. So, for example, if Dad had colon cancer diagnosed at the age of forty, I recommend you get a colonoscopy at age thirty. 

Everyone, regardless of their health, needs to have a colonoscopy at the age of fifty, but based on data released earlier this year by an American Cancer Institute study, I foresee the recommended age dropping.

Outside of this, symptoms that would necessitate a colonoscopy include:

  • Rectal bleeding

  • Anemia on blood tests (especially with iron deficiency)

  • Diarrhea lasting more than two to three weeks

  • Family history of colon cancer

  • Family history of colon polyps (especially if they occurred before the age of sixty)

  • Alteration in the bowel habits and stools

  • Unexplained weight loss

  • Fecal incontinence


How often should you get screened?


The interval of the colonoscopy depends on what is found, but is generally every three, five, or ten years. This depends on the number of polyps, the size, the characteristics of pathology, and other factors.


Besides colon cancer, what can a colonoscopy detect?


A colonoscopy can aid in the evaluation of chronic diarrhea (to look for microscopic colitis), causes of blood in stool such as Crohn’s disease/colitis or proctitis, evaluation of diverticulosis, unexplained abdominal pains, constipation, bloating, and evaluation of abnormalities found on other tests, like CT scans. A colonoscopy can also evaluate areas of the colon after a surgery.


How do you prep for a colonoscopy?


This is the most essential part of the procedure–and the one over which the patient has direct control.  

Two to three days leading up to the procedure, avoid eating heavy grains and vegetables that are difficult to eliminate. This includes fruits with lots of seeds, like raspberries and pomegranates. I specifically ask patients to avoid quinoa, farro, oatmeal, and granola, as the fiber load may be difficult to evacuate. Raw vegetables and fibrous fruits are also best avoided. A diet of white carbs that disintegrate well is preferred, but only during these two days prior to procedure. Acceptable foods include fish, pastas, rice, eggs, tofu, chicken noodle soup, and even sushi (but no sesame seeds, as they could clog the scope).

The morning before the colonoscopy, I allow for scrambled eggs and white bread (but no wheat or grainy breads). This is the last solid food the patient will have for 24 hours. After 10am, they will be only on clear liquids (water, iced tea, coffee, juice, popsicles, bone broth, chicken broth, and coconut water). One has to avoid anything red, as it will discolor the colon.

To thoroughly cleanse the colon, there are various prescription and non-prescription preparations. I prefer magnesium citrate because it’s cheap, safe, and effective. The night before the procedure, the patient drinks two 15-ounce doses of the magnesium citrate mixed with a clear liquid (I recommend 10 ounces of magnesium citrate with 20 ounces of ginger ale)–the first at 6pm and the second at 10pm. Both doses are necessary for a good result (meaning a colon devoid of solid stool). Some patients may choose to drink their second dose the morning of the colonoscopy–again, this is variable from physician to physician. Putting the liquid over ice, and drinking with a straw can make consumption easier–or using a menthol lozenge during the prep can help keep nausea at a minimum. The goal is to have a watery stool that has a light yellow tinge, signifying the colon is empty and its walls are clean.


Is the procedure safe?


It is beneficial to have a pre-procedure visit with your doctor to talk about what worries you, and to gain their perspective. The risk of complications is very low for this procedure, and the sedation is very safe, whether one uses twilight sedation (also referred to as conscious sedation) or deeper sedation with propofol (an IV medicine that induces deep sedation, and then leaves the body quickly and has no hangover effect), which requires an anesthesiologist to administer. This is not the same depth of sedation or the medicine used for surgical anesthesia, and is easier to recover from. Most patients are back to normal within 30 minutes after the procedure–but you can’t drive for the rest of the day due to the sedation.


How does the colon work–and what effect does it have on the rest of our health?


Health and disease start in the intestines, and the colon plays a very important role. We use phrases like “feeling crappy” or “gut feeling,” which are accurate descriptions. The body’s discomforts are often seated in our intestines, and specifically the colon.

The colon reabsorbs more than 99 percent of our body’s water, while eliminating waste products of digestion–and it also does much more to impact every aspect of our health. Within and around the walls of our intestines we have a huge nervous system that produces serotonin, which is why it is also called the “second brain.” Also, most of our immune system resides there. Abnormal functions in the immune system can result in colonic and small intestinal inflammatory diseases.

“We use phrases like ‘feeling crappy’ or ‘gut feeling,’ which are accurate descriptions.”

Whether we are experiencing bloating, gas, abdominal pain, constipation, or diarrhea, this may result in developing feelings of anxiety, depression, lethargy, and brain fog. There has been lots of research lately about the microbiome (the good bacteria). Let’s not forget that they live in the intestines, primarily the colon. A myriad of functions are being ascribed to the microbiome, from determining one’s metabolic rate and weight, to depression and anxiety, and most notably to IBS. Research is rampant and very exciting in this field, but very little is still known. Our mood may be great on the days we have a great functioning gut, and good eliminations. By the same token, I often see patients in my office suffering from chronic irregularity and discomfort of the elimination process. It is well known that IBS is one of the main reasons for a visit to the gastroenterologist.


What do you believe are the root causes of colon cancer?


Genetics is the main culprit. We know polyps can grow to become cancer–and removing them stops the process. Family history is the most significant risk factor for forming polyps (it can double or triple your risk). It is well known that a diet high in red meat and overly grilled, burnt, and barbecued foods, including beef, pork, fish, poultry, or smoked meats, can be one of the causes. Various studies since 1991 have revealed that the chemicals heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) that form in the process of panfrying or grilling food over fire are mutagenic and may increase cancer risks. The HCAs come from the burning of the substances found in the meat, and PAHs form when the fat and juices drip on the fire, creating flames that burn high and coat the food with these newly formed chemicals. Prolonged cook time, high temperatures, more well-done meats, and more smoke all may lead to more formation of these carcinogenic chemicals. 

Sedentary lifestyle, radiation for treatment of other cancers (uterine, ovarian, prostate) before the age of fifty, and a history of inflammatory bowel disease (ulcerative colitis or Crohn’s disease of the colon) all significantly increase the risk of colon cancer (up to four times). Other factors that increase your risk include a high fat or high calorie diet, smoking, alcohol, obesity, tall stature, a history of gallbladder removal, or a history of breast cancer or diabetes.


Is there anything that has been found to decrease the risk of colon cancer–or to otherwise improve colon functioning?


You could cut your risk of colon cancer in half by eating a diet high in vegetables, antioxidants, and fiber. Regular exercise, daily aspirin (one or two baby aspirin per day), could decrease colon cancer risk by 24 percent after a period of eight to ten years. Folic acid supplementation, adequate calcium supplementation, hormone replacement in postmenopausal women, and selenium supplements have also shown some benefit.

“You could cut your risk of colon cancer in half by eating a diet high in vegetables, antioxidants, and fiber.”

Still, none of these decrease your risk nearly as much as a regular screening schedule of colonoscopy and polyp removal.


What are some resources for finding a quality gastroenterology clinic?


Most patients rely on their primary care doctor to refer them to a gastroenterologist. A good strategy is to call your local hospital and ask the staff nurses, or technicians in the GI lab who they think does the best job at colonoscopy. Asking friends, family, and co-workers about their doctors is also a common practice. Don’t assume that going to a doctor at a large university will necessarily get you a great colonoscopy.

S. Radi Shamsi, M.D. is the founder of the Los Angeles Gastroenterology Clinic in Santa Monica. He’s a graduate of University of California, Los Angeles and University of California, Irvine College of Medicine. He also spent three additional years at the University of Southern California, Keck School of Medicine where he focused on gastroenterology and hepatology.

The views expressed in this article intend to highlight alternative studies and induce conversation. They are the views of the author and do not necessarily represent the views of goop, and are for informational purposes only, even if and to the extent that this article features the advice of physicians and medical practitioners. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice.

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