Screening Younger for Colorectal Cancer
A new American Cancer Society guideline recommends starting screening for colorectal cancer at age 45.
BY Kristie L. Kahl
PUBLISHED November 08, 2018
THANKS TO RECOMMENDED SCREENING starting at age 55, the overall incidence of colorectal cancer declined over the past two decades. However, there is a sobering exception to the encouraging trend: Among those under 50, the rate has risen 51 percent since 1994, according to the American Cancer Society (ACS).
In an attempt to help reverse this trend, the ACS has issued an updated guideline that calls for screening to begin at age 45 for individuals at average risk of colorectal cancer. Previously, the accepted U.S. standard was to start screening at age 50. Despite the faster rise in colorectal cancer among younger adults, incidence rates among those aged 45 to 49 are actually lower than those of people aged 50 to 54. The ACS attributes this partly to the uptake of screening at age 50, which results in a higher rate of detection of the disease, including cases that are early and asymptomatic.
“(Implementing the ACS guidelines) is a way to prevent this disease from happening in younger persons,” Susan K Peterson, Ph.D., M.P.H., of the department of behavioral science in the division of cancer prevention and population sciences at The University of Texas MD Anderson Cancer Center in Houston, said in an interview with CURE®. “(And it is) one way to potentially stem the occurrence of these cancers and the morbidity and mortality from them.” Screening can lead to removal of premalignant polyps before they turn into cancer, and to earlier detection of cancers that have already developed, improving health outcomes compared with later detection.
The ACS based its recommendation on colorectal cancer incidence rates, a computer model that demonstrated a benefit to screening beginning at age 45, and the expectation that this will lead to catching the disease earlier, just as it has for older adults. The guidelines, recently published in CA: A Cancer Journal for Clinicians, recommend the following:
• Adults aged 45 and older at average risk of colorectal cancer should undergo regular screening — either with a high-sensitivity stool-based test or a visual exam such as a colonoscopy, depending on patient preference and test availability or insurance coverage.
• All positive results on non-colonoscopy screening tests, such as fecal occult blood, should be followed up with timely colonoscopy.
• Average-risk adults in good health with a life expectancy of greater than 10 years should continue screening through age 75; for those 76 to 85, clinicians should individualize screening decisions based on patient preference, life expectancy, health status and prior screening history. Those over 85 should be discouraged from continuing colorectal cancer screening.
“The guidelines do not recommend only going (with) colonoscopy — which is oftentimes considered the gold standard of screening tests — so patients have a choice of what test they can use,” Peterson said. “Sometimes a colonoscopy can be a bit off-putting.”
Patients can be screened annually with a fecal immunochemical test or a high-sensitivity guaiac-based fecal occult blood test, both of which detect blood in the stool; every three years with a multitarget stool DNA test, which can detect not only blood in the stool but also abnormal DNA; every five years with CT colonography (a virtual colonoscopy using X-ray equipment) or flexible sigmoidoscopy (which examines the lower part of the large intestine); or every 10 years with a colonoscopy, which examines the entire colon.
WHAT TO KNOW
To follow the new guidelines, the first step for patients is to find out if any relatives have or had cancer. “If you have a family history of colon cancer, you may benefit from being testing for an inherited gene mutation that indicates you have one of the known hereditary cancer syndromes,” Peterson said. Even if those syndromes are ruled out, having a first-degree relative who was diagnosed with colorectal cancer increases an individual’s risk, she said: “Everyone should know their family history, be aware of it and share that information with their doctors.”
In addition, patients’ discussions with their doctors should start before age 45 to at least determine when screening should start. Any middle-aged or younger individuals who have symptoms, such as abdominal pain, blood in the stool, narrowing of stools or fatigue, but are dismissed by a health care professional because of their age, should seek a second opinion.
“Talking about this, although uncomfortable, and becoming aware is really important,” Peterson said. “Boiling it down: This should be a wakeup call that if you are younger than 45 and are identifying symptoms that might be related to colorectal cancer, go see your doctor, and do not put it off.”