Colonoscopies Still the Best Tool for Preventing Colorectal Cancer

By Pat Carragher - October 18, 2022

Colonoscopies have long been considered the gold standard for catching and preventing colorectal cancer, the second most common cause of cancer deaths in men and women combined in the United States. A recent European study is raising the question: Are the benefits of colonoscopies for cancer screening overrated?

The study, published in The New England Journal of Medicine, looked at colonoscopies compared to no cancer screening in a randomized trial. The study found that the group of people who were invited to undergo a colonoscopy had an 18% lower risk of getting colorectal cancer and no significant reduction in the risk of death.

While that number seems disappointing on the surface, it’s important to understand more about the details of the study. A deeper look into the data showed that more than half of the research participants who were invited to get a colonoscopy never actually showed up for the procedure.

Among the group who did undergo a screening colonoscopy, the risk of developing colon cancer decreased by about 31%. More importantly, deaths decreased by about 50%.

“For this study there may not be enough time elapsed to really measure if the removal of those polyps had the intended effect,” said Dr. Mark Friedman of the Gastrointestinal Oncology Program at Moffitt Cancer Center. “If they look at those patients again in 10 to 15 years, the results could be much different. Additionally, almost half the group in the colonoscopy arm didn’t actually undergo a colonoscopy, so the results don’t exactly make sense.”

For Moffitt President and CEO Dr. Patrick Hwu, when it comes to preventing colorectal cancer, the science is simple.

“We have decades worth of data to back this up. We know colonoscopies work,” Hwu said. “This is the most effective tool we have to decrease deaths from colon cancer.”

Friedman also points to the fact that 16 of the 35 endoscopists in the study did not meet the standard for colonoscopy benchmarks, noting that they either didn’t get all the way to the end of the colon or didn’t have the required polyp detection and removal rate. Additionally, sedation is standard for patients undergoing colonoscopy in the U.S. but is less common in Europe. Sedation minimizes patient discomfort and keeps providers from rushing through it.

“The real point of screening colonoscopy is to prevent the development of colon cancer,” Friedman said. “When we can remove those polyps and precancerous lesions, it makes colonoscopies a really important tool. When you look at the patients in this study that actually underwent colonoscopies as recommended, there was a significant difference in death rate.”

portrait of blockquote author

"When you look at the patients in this study that actually underwent colonoscopies as recommended, there was a significant difference in death rate."

- Dr. Mark Friedman, Gastrointestinal Oncology Program

Sobering Statistics
According to the American Cancer Society, nearly 53,000 people will die of colorectal cancer this year. The data show that for Americans ages 45 to 49, there are about 7,000 new colorectal cancer cases per year and about 1,800 deaths. This group accounts for about half of colorectal cancer diagnoses occurring under the previous recommended age of 50 to begin screening.

After considering recent trends of increasing cases of colon cancer in younger people, the U.S. Preventive Services Task Force recommended that people of average risk start colorectal cancer screenings at age 45.

People of average risk include those with no prior diagnosis of colorectal cancer, no family history or genetic disorders that increase your risk of disease, no history of precancerous polyps and no diagnosis of inflammatory bowel disease.

In addition to colonoscopy, other recommended screenings include computed tomography colonography and stool-based tests with high sensitivity such as fecal immunochemical tests (FIT) that are widely accessible and would require a colonoscopy follow-up if the test comes back abnormal.

The FIT is done once a year and uses antibodies to detect evidence of human blood in the stool. For this test, you receive a test kit from your health care provider to perform at home. You use a brush to obtain a small amount of stool and return the test kit to the doctor or lab, where the samples are checked for the presence of blood, which would suggest need for further testing. FIT tests do not detect polyps or cancer, so a positive test must be followed up by a colonoscopy.

Success with FIT Kits

Dr. Clement Gwede, Senior Member, Health Outcomes and Behavior
Dr. Clement Gwede, Senior Member, Health Outcomes and Behavior

Dr. Clement Gwede, a researcher at Moffitt who focuses on health disparities, leads a team focused on helping people get screened for colon cancer through FIT tests. Gwede has led several studies in which over 80% screening was achieved for colorectal cancer, meaning that over 80% of people who received the FIT kits returned them.

“Many times we hear patients say they will not undergo screening because they feel well or are not experiencing any symptoms. Some say ‘I know my body; I can tell when something is wrong,’” said Gwede. “That is not exactly true. We think we know our bodies, but cancer often grows quietly without causing any symptoms, and by the time it causes any signs or symptoms — whether minor bleeding or aches and pains — it may be too late.  For some patients who are not at increased risk, home stool tests are widely available and a good option if they cannot readily get a colonoscopy, but any abnormal result must be followed up with a colonoscopy.”

Dr. Susan Vadaparampil, Associate Center Director, Office of Community Outreach, Engagement and Equity
Dr. Susan Vadaparampil, Associate Center Director, Office of Community Outreach, Engagement and Equity

Dr. Susan Vadaparampil, associate center director of Community Outreach, Engagement and Equity at Moffitt, leads a team focused on removing barriers to access by bringing guideline-based cancer screenings to diverse and underserved communities. Moffitt’s screening access program works with community partners to offer home-based colon cancer screening, for example, and also connects people to crucial follow-up care for abnormal results.

“To achieve equity, we must engage in intentional strategies where care is delivered to support both patients and those that deliver their care,” Vadaparampil said. “To achieve the greatest impact, we must also incorporate larger scale efforts through policy and technology, while keeping the needs of all patients at the forefront.”

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