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. According to the American Cancer Society, colorectal cancer rates have been increasing since the mid-1980s in young adults aged 20 to 39, and since the mid-1990s in adults aged 40 to 54, with younger age groups experiencing the greatest increase.

From 2000 to 2016, young adults between the ages of 20 and 39 experienced the greatest increase in distant-stage early-onset colorectal adenocarcinoma, and this rise in cases disproportionally affected young Black and Hispanic adults, according to the results from a study by Montminy et al published in Cancer Epidemiology, Biomarkers & Prevention. Optimizing earlier screening initiatives and risk-stratifying younger patients by symptoms and family history are critical to counteracting rising distant-stage colorectal cancer in this age group, according to the study authors.

Study Methodology

The researchers analyzed annual incidence data from from 103,975 patients included in the United States Surveillance Epidemiology and End Results (SEER) 18 cancer registry from the years 2000 to 2016 stratified by stage (in situ, localized, regional, and distant in patients age 20 to 29, 30 to 39, 40 to 49, and 50 to 54); subsite (colorectal, rectal-only, and colon-only); and race (non-Hispanic White, non-Hispanic Black, and Hispanic).

Three-year average annual incidence rates changes (pooled 2000–2002 incidence rates compared with 2014–2016) and cancer stage proportions (percent contribution of each cancer stage) were calculated.

Results

The researchers found that the steepest percent increases in incidence rate occurred for distant-stage colorectal adenocarcinomas and were most pronounced for younger age groups. For colon-only distant-stage adenocarcinoma, the steepest increase in incidence rate occurred among patients 30 to 39 years old, who experienced a 49% increase between 2000 and 2016. For rectal-only distant-stage adenocarcinoma, the greatest increase in incidence between 2000 and 2016 occurred among 20- to 29-year-olds (133% increase), followed by 30- to 39-year-olds (97% increase) and 40- to 49-year-olds (48% increase). Corresponding decreases in the incidence of early-stage disease were observed among these subgroups.

The researchers also found that younger age was associated with an increased risk for distant-stage colorectal cancer. Patients who were 20 to 29 years old had a 29% likelihood of presenting with distant disease, compared with a 20% likelihood for 50- to 54-year-olds.

Distant-stage colorectal adenocarcinoma proportions increased among young patients between the years 2000 to 2002 and 2014 to 2016, with the greatest increases observed among 20- to 29-year-olds (18% distant-stage between 2000–2002 vs 31% between 2014–2016) and 30- to 39-year-olds (20% vs 29%) for rectal-only disease.

When the proportions of distant-stage disease were analyzed by race/ethnicity, the researchers found that the largest increases in distant-stage rectal adenocarcinoma proportions from the years 2000 to 2002 to 2014 to 2016 occurred among 20- to 29-year-old non-Hispanic Black individuals (0% vs 46%), 20- to 29-year-old Hispanic individuals (28% vs 41%) and 30- to 39-year-old non-Hispanic Black individuals (21% vs 33%). For colon adenocarcinoma, distant-stage proportion increased most among 20- to 29-year-old non-Hispanic Black individuals (20% distant-stage in 2000–2002 vs 34% in 2014–2016).  

“Youngest patients show greatest burdens of distant colorectal adenocarcinoma. Although affecting all races, burdens are higher in non-Hispanic Black and Hispanic subgroups, although case counts remain relatively low. Optimizing earlier screening initiatives and risk-stratifying younger patients by symptoms and family history are critical to counteract rising distant-stage disease,” concluded the study authors. 

Clinical Significance

“We found that proportions of distant-stage colorectal cancer increased over time in most early-onset subgroups, with a corresponding decrease in early-stage disease, and that there is a direct correlation between younger age and the likelihood of presenting with distant-stage disease,” said senior study author Jordan J. Karlitz, MD, Chief of the Gastrointestinal Division at Denver Health Medical Center and Associate Professor at the University of Colorado School of Medicine, in a statement. “Although the increasing burden of early-onset colorectal cancer affects all races, these increases seem to be particularly prominent in the youngest non-Hispanic Black and Hispanic subgroups, although absolute case counts remain relatively low.”

Disclosure: For full disclosures of the study authors, visit cebp.aacrjournals.org.