Data Analysis on Early-Onset Colorectal Cancer Sheds Light on the Rising Rates in Young Adults

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In May 2021, the U.S. Preventive Services Task Force (USPSTF) announced that it was updating its recommendation for when individuals at average risk of colorectal cancer should begin screening. Echoing the recommendation from the American Cancer Society in 2018, the USPSTF now recommends that those at average risk begin screening exams at age 45 instead of age 50. The news came at a time when research is showing alarming trends in colorectal cancer among younger adults. The disease has seen declines in incidence by 3.3% annually among people older than 65 and declines in related mortality for this group by 3% annually. However, among individuals younger than age 50, the incidence rate has risen by about 2% annually, and death rates have increased by 1.3% annually.1

Colorectal cancer is the second most common cause of death in the United States. In 2020, approximately 148,000 people were diagnosed with the disease, and 53,200 people died from it, including 17,930 cases and 3,640 deaths in individuals younger than age 50.1

In an exclusive analysis conducted for The ASCO Post, the data analytics company Komodo Health looked at differences in symptoms, screening rates, and time to treatment between younger and older adults diagnosed with colorectal cancer. The data may shed light on incidence trends in this younger population of patients.

Tabby Khan, MD, MPH

Tabby Khan, MD, MPH

In this analysis, Tabby Khan, MD, MPH, Medical Director of Komodo Health, examined the rates of red flag symptoms among three age groups of patients: younger than age 35; 35 to 49; and 50 and older. She also explored the top medical specialties evaluating and treating patients by age group and the duration between symptoms and diagnosis to treatment. The screening rates included here are likely lower than those seen in real-world settings, according to Dr. Khan, because this analysis included ICD-10 codes only. Here are her findings.

Rates of Red Flag Symptoms by Age

According to the analysis, the frequency of claims for red flag symptoms differed greatly among the three age groups of patients. For example, patients younger than 35 were more likely to present with “unspecified abdominal pain” than patients in the other age groups: 32%, 29.26%, and 22.13%, respectively. Patients aged younger than 35 also experienced higher rates of constipation, nausea, vomiting, and diarrhea than patients in the two older age groups. Anemia rates were comparable in the youngest and oldest cohorts, 25.32% and 27.86%, respectively, but lower, 19.69%, in the age 35 to 49 cohort.

“The high rate of unspecified abdominal pain and general gastrointestinal symptoms in the youngest cohort suggests that providers need to consider colorectal cancer as part of a differential diagnosis in younger patients, and consider invasive testing, such as colonoscopy in patients whose symptoms are not explained by more common etiologies,” said Dr. Khan.

The highest rate of anal and rectal bleeding events occurred among patients aged 35-49, 19%, vs 14.37% in patients younger than 35 and 12% in patients 50 and older.

As expected, the screening rate of patients in the youngest age cohort was extremely low, just 5%, vs 11% in the age 35 to 49 cohort and 28.14% in the age 50 and older cohort.

According to the screening trends, the presence of benign disease and/or polyps was significantly higher in the 35 to 49 and 50 and older cohorts than in the 35 and younger cohort.

Specialties Evaluating Symptoms 

Emergency medicine topped the list for evaluation of the first red flag symptoms for patients younger than 35, which is in sharp contrast to the two other age groups, who chose gastroenterologists for evaluation.

Family practice and internal medicine both ranked higher across all age groups, underscoring the importance of primary care providers in identifying red flag symptoms, according to Dr. Khan.

Time From Diagnosis to Treatment

The number of days from when patients experienced their first symptoms to treatment initiation was similar across all age groups, although patients in the two younger age groups had slightly shorter intervals: younger than 35: 230.9 days; 35 to 49: 203.2 days; and 50 and older: 256.7 days.

“This finding was somewhat surprising. However we hypothesize that this may be because younger patients often wait until their condition has become more severe before seeking care,” said Dr. Khan. “This is also supported by our findings that the younger patient cohort is most likely to present in the emergency department first.”

The time from diagnosis to surgical treatment was shortest for patients in the 35 and younger cohort. “This is likely because these patients are more medically fit for surgery and do not require extensive anesthesia evaluation,” explained Dr. Khan. 

DISCLOSURE: Dr. Khan reported no conflicts of interest.


1. Siegel RL, Miller KD, Sauer AG, et al: Colorectal cancer statistics, 2020. CA Cancer J Clin 70:145-164, 2020.