Colorectal Cancer Screening

Colorectal cancer almost always develops from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find precancerous polyps, so they can be removed before they turn into cancer. Screening tests can also find colorectal cancer early, when treatment works best.

Colon and Rectal Cancer: Understanding the Difference

While colorectal cancer screening is crucial for both colon and rectal cancers, it's important to understand the distinctions between these two types. Rectal cancer specifically develops in the last several inches of the colon, and its symptoms and treatments can differ from colon cancer. Incorporating both colon and rectal cancer screening is vital for comprehensive cancer care but the screening process is able to encompass both which is why these types of cancer are often screened together.

According to the American Cancer Society, colorectal cancer is one of the leading causes of cancer death for both men and women in the United States. The death rate of colorectal cancer has been dropping for several decades because colorectal polyps are now more often found by screening and removed before they can develop into cancers.

A colorectal cancer screening can help detect cancer early, making treatment more successful.

Colorectal cancer screening methods can be divided into two categories:

Visual Exams

Colonoscopy

A colonoscopy evaluates the entire length of the colon and rectum, using a colonoscope, a flexible tube with a light and a camera on the end. This test looks for polyps or other abnormal areas that can be removed and sent to a lab for testing.

Flexible Sigmoidoscopy

A sigmoidoscopy is similar to a colonoscopy, but it does not evaluate the entire colon. The sigmoidoscope is only about 2 feet, or 60 cm long, and is used to evaluate the rectum and lower part of the colon. This test looks for polyps or other abnormal areas that can be removed and sent to a lab for testing.

Stool-based Tests

Fecal Occult Blood Test (FOBT)

Fecal Occult Bloods Tests require patients to collect a small sample of stool at home, then send it to a provider or lab to test. This test looks for hidden or occult blood in the stool.

Stool DNA tests

Stool DNA tests require patients to collect an entire bowel movement, then send it to a provider or lab to test. This test helps identify abnormal DNA shed in stool from polyps or cancer and looks for hidden or occult blood in the stool.

Screening tests, such as the fecal immunochemical test and stool DNA test, play a crucial role in detecting colorectal cancer early. Identifying key risk factors, including age, family history, and lifestyle choices, helps in determining the appropriate screening method and frequency.

The American Cancer Society recommends that people at average risk of colorectal cancer start regular screening at age 45, and continue regular colorectal cancer screening through the age of 75.

Colorectal cancer screenings look for colon polyps, which are precursor lesions to cancer. Polyps typically don’t cause any symptoms. Screening also helps identify patients at high risk, or those with multiple or large polyps, who need closer monitoring.

A colonoscopy is one of the few screening tests that has shown to lower the risk of developing colon cancer by facilitating early detection of polyps.

Anyone can get colorectal cancer. But there are some factors that can increase your risk, such as

• Age: Most who have this cancer are over age 50, but it can occur at any age.

• Race and ethnicity: African Americans have the highest risk for colorectal cancer in the United States, and Ashkenazi Jews, whose families come from Eastern Europe, have one of the highest colorectal cancer risks of any ethnic group in the world.

• Gender: Men have a slightly higher risk of this cancer than women. 

• History of colorectal polyps: Growths in your colon and rectum are common in adults over age 50, and are often not cancerous but over time, some polyps can become cancerous. If you have had polyps, or adenomas, in the past, you may be more likely to develop colorectal cancer.

• History of colorectal cancer and some other cancers: Those who have had colorectal cancer have an increased risk of recurrence. Women with a history of cancer of the uterus or ovaries also have a higher risk for colorectal cancer.

• Ulcerative colitis or Crohn's disease: Those who have an inflamed lining of the colon, or inflammatory bowel disease, caused by  Ulcerative colitis or Crohn's disease have a greater risk for colorectal cancer.

• Family history: People are at higher risk if they have a family history of colorectal cancer or polyps in a first-degree relative, such as a parent, sibling or child. This risk is greater if the relative was diagnosed before age 45, or if more than one relative was diagnosed. Still, most people with colorectal cancer don’t have a family history of the disease.

• Certain inherited syndromes: Those with certain syndromes have a very high risk of colorectal disease, including familial adenomatous polyposis (FAP) and Lynch syndrome (also called hereditary nonpolyposis colon cancer or HNPCC). 

• Obesity: Colorectal cancer is more common in people who are very overweight, and this is more true for men. 

• Not being active: Those who have a sedentary lifestyle are at increased risk of the disease.

• Diet: Colorectal cancer is linked to a diet high in red meats, including beef, pork, lamb and veal. It's also linked to a diet high in processed meats, such as hot dogs and lunch meats.

• Drinking a lot of alcohol: Those who consume a lot of alcohol are more likely to get colorectal cancer.

• Type 2 diabetes: Those with type 2 diabetes are more likely to get colorectal cancer.

• Smoking: Smoking raises risks for this cancer.

Talk to your healthcare provider to see if you are at a higher-than-average risk for colon cancers because of family history, genetic disorders or other factors.

A healthy lifestyle may help to lower your risk for colorectal cancer. This includes:

• Being physically active: Getting at least 150 minutes of moderate-intensity physical activity each week can reduce your risk for colorectal cancer. Even fast walking and climbing stairs can help lower your risk. At least 75 minutes of intense physical activity each week also lessens risks, which includes running and aerobics. This is true even if you start exercising later in life. 

• Eating lots of fruits, vegetables, and whole grains: A diet that’s high in these foods can help lower your colorectal cancer risk. Experts don’t know if some vegetables or fruits might be better than others in lowering risk, so it's best to eat a variety.

• Limiting red and processed meats: Limit beef, pork, sausage, hot dogs, deli meats and bacon in your diet. Instead, eat lean meats and fish.

• Staying at a healthy weight: Being overweight or obese is linked to an increased risk of colorectal cancer and some other cancers.

• Not smoking or abusing alcohol: Both smoking and heavy alcohol use can raise the risk of colorectal cancer. Not smoking and limiting alcohol may help lower your risk. 

• Getting enough calcium in your diet: Some studies have found that higher calcium intake may lower the risk of colorectal cancer. However, other research has found that more calcium may raise the risk of prostate cancer in men. Talk with your provider before you take calcium supplements.  

Community health initiatives play a vital role in increasing awareness and accessibility of colorectal cancer screenings. These programs often focus on underserved populations and aim to educate the public about the importance of regular screenings.

Participation in clinical trials can offer access to new and potentially more effective colorectal cancer screening methods. These trials are essential for advancing medical knowledge and improving screening techniques.