Updated colorectal cancer screening guidelines: What to know

Today, the American Cancer Society released an update to their colorectal cancer screening guidelines. They now recommend average-risk adults begin screening for colorectal cancer at age 45 rather than age 50, as their previous guidelines stated.

The lowered age for screening comes in response to scientific studies that show the rates of colorectal cancer are increasing among younger adults.

We spoke with our Y. Nancy You, M.D., to learn more about the new guidelines and what they mean.

How do the American Cancer Society’s new guidelines differ from current colorectal cancer screening recommendations? Why do you think they have made this change?

The biggest difference with the new guidelines is that the age to start colorectal cancer screening for average-risk adults has now been lowered to 45 from 50. The guidelines also allow for a variety of screening tests, acknowledging that patient preferences and local test availability are important considerations for those being screened. 

I think there are several motivations for this change. First of all, there has been strong evidence over the past few decades for an increasing colorectal cancer rates among young adults ages 18-50, especially for rectal cancers, which are more complicated to treat. There is also strong evidence these trends will continue over time.

Additionally, there is a strong desire and a high level of motivation to reduce premature deaths from colorectal cancer. Almost 70% of colorectal cancers diagnosed below age 50 are already stage III or IV, meaning the cancer has spread to the lymph nodes or beyond. When diagnosed at earlier stages, current treatment options are more successful.

What about individuals younger than 45? What should they look out for?

There are a few key things for these individuals to consider.

First, a portion of younger patients with colorectal cancer have a hereditary condition or other medical conditions that increase their risk of this disease. So, it’s important to know your family history and understand associated cancer risks. 

Younger adults should also look out for symptoms that may be consistent with colorectal cancer, such as pain, bleeding, altered bowel habits or a changing stool pattern. Don’t be shy about talking to your physician about your bowels.  

Finally, maintain a healthy lifestyle to minimize your colorectal cancer risk. Healthy lifestyle behaviors include eating a plant-based diet, getting regular exercise, keeping a healthy weight, and avoiding tobacco use and excessive alcohol consumption.

What recommended screening tests are available for colorectal cancer, and how do they differ?

There are two main types of screening tests for colorectal cancer — stool-based tests and visual exams.

Stool-based tests include the fecal immunochemical test (FIT), fecal occult blood test (FOBT) and stool DNA tests. These tests do not involve physically looking inside the colon and rectum, and so they are less invasive and less expensive. However, they need to be performed more frequently (every 1-3 years) and, if an abnormal result is found, a visual exam is needed to identify what is exactly wrong and suggest a course of follow-up action.

Visual exams, which include the colonoscopy, virtual colonoscopy (CT colonography) and flexible sigmoidoscopy, involve directly examining the inside of the colon and rectum where polyps and other diseases arise. They do involve a certain amount of preparation and an office procedure. They are very safe, but like any procedure, are not risk-free. These are performed less frequently than stool-based tests, generally every 5-10 years. If something abnormal were found, further diagnostic or treatment procedures (such as removing a polyp) can be done right away. 

How would you counsel someone on when to begin colorectal cancer screening?

First, learn about the reasons the age was lowered. It’s important to understand the increase in disease burden and the importance of early diagnosis, as well as the ability for screening tests to diagnose cancers or precancerous at the earliest stages, when they are more treatable or curable.

Also, learn about the different screening tests available and make the best decisions for yourself based on factors such as convenience, availability and insurance coverage. My best advice is to pick the test you’re most comfortable with and mostly likely to stick with long-term.

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