Digestive Health

What you need to know about colorectal cancer screenings, prevention and risk

What you need to about colorectal cancer screenings, prevention and risk


Colonoscopy screenings can prevent cancer and healthy lifestyle choices can reduce colorectal cancer risk


By Dr. Steven Gorelick, System Chair of the Digestive Health Institute, Nuvance Health


If you are like most people, you might feel uncomfortable talking about colorectal health — even with your doctor. The truth is that your colon, or the large intestine, is a critical part of your digestive system, important to your overall health and well-being, and worth talking about — especially now when colorectal cancer is increasing among younger people.

Here are answers to questions many people have about colorectal cancer, colonoscopy screenings, prevention and reducing risk.


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What is colorectal cancer?

Colorectal cancer starts in the colon (colon cancer) or rectum (rectal cancer). Cancer develops when cells in your colon or rectum grow out of control. It begins as a growth in the lining of the colon or rectum called a polyp. If left untreated, some polyps can turn into cancer.


Besides some types of skin cancer, colorectal cancer is the third most common cancer in the United States. It is also one of the most preventable cancers because of colonoscopy screenings. 


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What is a colonoscopy screening?

A colonoscopy screening is a procedure to see inside the colon. A screening is for people who do not have symptoms but is a proactive way to detect possible health concerns and address them early.

Video: See what it’s like to get a colonoscopy screening


Doctors who specialize in gastroenterology perform colonoscopies using a thin, flexible tube with a tiny light and video camera at the end of it, called a colonoscope. This same-day, or outpatient, procedure usually takes about 15 to 30 minutes on average.


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Patients must complete a bowel prep before having a colonoscopy. There are different kinds of prep that may include eating a special diet and drinking a liquid laxative a day or more before the procedure. The prep is important because it cleans out the colon so the doctor can clearly see the inside during the procedure.


During the procedure, the doctor inserts the colonoscope into the anus and then guides it through the rectum and colon to look for changes or irregularities, such as precancerous polyps. This occurs while the patient is comfortable and sedated throughout the procedure.


When do you start colonoscopy screening?

People who are at average risk for colorectal cancer should start having colonoscopy screenings at age 45.


People who have a family history of colorectal cancer or other risk factors may need to start screenings earlier.


What causes colorectal cancer?

Risk factors are conditions or habits that may increase the chances of getting a disease like cancer. Speak with your doctor to determine your risk of developing colorectal cancer. Some risk factors you cannot control, like your age, while others you can change to reduce risk, such as diet.


Colorectal cancer risk factors

Factors associated with an increased risk of colorectal cancer you cannot change

  • Age: Colorectal cancer is more common in people age 50 and older
  • Family health history: First-degree relative (parent, sibling or child) who had colorectal cancer or precancerous polyps
  • Personal history: Inflammatory bowel disease, personal history of colorectal cancer or polyps, or genetic predisposition to colorectal cancer such as Lynch syndrome
  • Ethnicity and race: People from Ashkenazi Jewish or African American descent are at increased risk for colorectal cancer


Lifestyle factors associated with an increased risk of colorectal cancer you can change

  • Diet: Eating an unhealthy diet high in fats, salt, sugar and processed foods
  • Exercise: Being sedentary, or inactive
  • Moderate to heavy alcohol use: According to the Dietary Guidelines for Americans, moderate alcohol consumption is defined as having up to one drink per day for women and up to two drinks per day for men; heavy alcohol use is defined as consuming eight drinks or more per week for women, and 15 drinks or more per week for men
  • Smoking tobacco
  • Unhealthy weight: Being overweight or obese


How to prevent colorectal cancer

A colonoscopy is a preventive screening because the doctor can remove precancerous polyps during the exam before they have a chance to turn into cancer.


It can also detect cancer early before it causes symptoms and when it is more treatable.


Share your personal and family health history with your doctor to determine your potential hereditary risk for colorectal cancer. Your doctor may recommend you start colonoscopy screenings before age 45 depending on this information.


Consider the lifestyle factors you can change to reduce your risk of developing colorectal cancer. Speak with your doctor if you need support or resources to follow a healthy diet, get regular exercise or quit smoking. The good news: These lifestyle modifications can also reduce your risk of developing other types of cancer, diabetes, heart disease and obesity.


In addition to managing lifestyle risk factors, start routine colonoscopy screenings at age 45 if you do not have a personal or family history that increases your risk for colorectal cancer.


Is there an alternative to a colonoscopy?

We recommend colonoscopy screenings for most people because we can remove precancerous polyps and prevent colorectal cancer. According to the American Cancer Society, the rate of colorectal cancer diagnoses is dropping among people 65 and older, thanks to screenings.


However, we understand some people may not want to have a colonoscopy because they cannot tolerate the prep or for other reasons.


The most important thing is to find a screening test that works well for you rather than not have them at all. There are at-home stool sample tests that are available by prescription. These tests may be able to detect colorectal cancer early.


What should I know about colorectal cancer in young adults?

Colorectal cancer screenings are not recommended for people at average risk younger than 45. However, younger adults can also get it. In fact, colorectal cancer in younger adults is on the rise in the United States.


Follow a healthy lifestyle, pay attention to unusual symptoms and see your doctor if you have:

  • A change in bowel habits, such as constipation or diarrhea that lasts for more than a few days
  • A feeling that you need to have a bowel movement that is not relieved by having one
  • Rectal bleeding with bright red blood
  • Blood in the stool, which might make the stool look dark brown or black
  • Cramping or abdominal (belly) pain
  • Weakness and fatigue
  • Unintended weight loss


The bottom line: Colonoscopy screenings can prevent colon or rectal cancer from developing or detect it early when it is more treatable. Take control of your health by following a healthy lifestyle to reduce your chances of getting colorectal cancer. Talk with your doctor about your risk factors to determine when you should start colonoscopy screenings.


Dr. Steven Gorelick is a board-certified gastroenterologist, and the system chair of the Digestive Health Institute at Nuvance Health. Book now with Dr. Gorelick.


Dr. Steven Gorelick, Senior Medical Director, Nuvance Health Medical Practice Gastroenterology