Rising Burden of CRC in Young Adults: An Urgent Need to Address the Issue
Swati G. Patel, MD, MS
Assistant Professor, Medicine-Gastroenterology
The University of Colorado School of Medicine
Citation: Patel SG. Rising burden of CRC in young adults: an urgent need to address the issue [published online March 18, 2020]. Gastroenterology Consultant.
The incidence and mortality rates associated with colorectal cancer (CRC) in the United States have been declining over the last several decades, in large part because of an increased uptake of CRC screening.1 Unfortunately, the opposite trend has been observed among patients younger than age 50 years. There has been a 51% increase in CRC incidence in this age group, and an 11% increase in CRC-associated mortality.2 If current trends continue, by the year 2030, 10% of all colon cancers and 22% of all rectal cancers in the United States are expected to be diagnosed in patients younger than age 50 years.3
Early age onset CRCs (EOCRC) are more likely to occur in the left colon, particularly the rectum, than later-age onset CRCs. They also are more likely to have aggressive histology, such as mucinous features and signet ring cells, and tend to be diagnosed at later stages.4 Patients with EOCRC are more likely to have symptoms—bleeding or change in bowel patterns—and have a significantly longer delay from symptom onset to diagnosis, compared with older patients (217 days vs 29 days).5
The exact cause of this alarming trend is not clear. Approximately 16% of all CRCs diagnosed in patients younger than age 50 years are associated with a genetic predisposition.6 A substantial proportion of the remaining patients with nongenetic EOCRC may have a family history of CRC or advanced precancerous colorectal polyps—established risk factors for CRC at younger ages. Among individuals with no genetic condition and no family history of colorectal neoplasia, the cause of earlier age of diagnosis is unclear.
Established risk factors for CRC in older patients, such as diabetes,7 obesity,8 and excess alcohol intake,9 may be contributing to the increasing incidence, given the increasing public health burden of these conditions. Novel risk factors have also been proposed, including alterations in the gut microbiota (ie, from antibiotic use) or changes in environmental exposures such as radiation or carcinogens in the water supply. There is limited data about these potential contributors,10 and ongoing epidemiologic research is needed to better characterize risk factors.
Regardless of the etiology of the rising burden of CRC in younger patients, there is an urgent need to address the issue. There should be continued efforts in improving recognition of those with hereditary/genetic cancer syndromes, since we have effective cancer-prevention options for these patients such as colonoscopy screening or prophylactic surgery.
In addition to recognizing familial syndromes, it is critically important to collect and act on family history of CRC and advanced colorectal polyps to institute appropriate screening. Current guidelines11,12 support screening first-degree relatives of those with CRC or an advanced colorectal polyp at age 40 years (or 10 years prior to CRC/advanced polyp diagnosis). These populations are under-screened and provide an immediate opportunity to identify high-risk individuals. Given the delays observed between symptom onset and diagnosis, it is crucial that providers thoroughly evaluate symptoms—rectal bleeding, change in bowel patterns, unintentional weight loss, unexplained abdominal pain or anemia—and exercise a low threshold for lower endoscopic examination, regardless of the age of the patient.
Finally, professional societies are considering decreasing the age for average-risk CRC screening to address the increasing disease burden in younger patients. In 2018, the American Cancer Society proposed a qualified recommendation to offer screening at age 45 years instead of at age 50 years,13 an approach shown to be cost-effective.14
The increasing burden of EOCRC demands increased awareness by all medical providers and younger patients. As we learn more about the causes, there are multiple strategies that can be immediately implemented to curb this alarming trend.
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