Early-onset colorectal cancers may be becoming more common in young people between the ages of 20 and 39 years old, according to a new study, with the increase appearing more pronounced in Black and Hispanic populations.
The study, published Wednesday in the journal Cancer Epidemiology, Biomarkers & Prevention, tracked increases in incidences of early-onset colorectal adenocarcinoma, specifically cases which had already progressed to a late stage of the cancer, reported in the U.S. between 2000 and 2016.
Early-onset refers to cancer in patients younger than 50 years of age, and colorectal adenocarcinoma is a type of cancer that starts in the large intestines and can spread from there. Colorectal cancer is the third-most common cancer in Canada.
Researchers found that the biggest increases were in distant-stage colorectal adenocarcinomas, and that the increases became more pronounced the younger the patients were.
This means that while there was a 48-per-cent increase from 2000 to 2016 in the incidence rate of rectal-only distant-stage adenocarcinoma in patients 30-39 years of age, there was a 133-per-cent increase in the same cancer in patients aged 20-29 years in that same time period.
They also found that not only did incidence rates change, but there was an increased risk for those with younger ages when it came to distant-stage colorectal cancer. Patients aged 20-29 years old had a 29-per-cent likelihood of presenting with an advanced stage of the disease, compared with a 20 per cent likelihood for those aged 50-54.
The study also looked at cancer rates as they pertained to race, looking at three categories of patients: Hispanic people, non-Hispanic white people, and non-Hispanic Black people.
And the largest increase of cancer incidence were among Hispanic people and Black people, with incidence rates more than doubling for some types of colorectal cancers.
“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,” Dr. Jordan Karlitz, author of the study and an associate professor at the University of Colorado School of Medicine, said in a press release.
“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.”
In order to conduct the study, researchers looked at annual incidence data reported by the Surveillance, Epidemiology, and End Results (SEER), a government source of cancer statistics in the U.S. They looked at data on more than 100,000 patients with colorectal adenocarcinoma.
Many previous studies have looked at early-onset incidence rates of colorectal adenocarcinoma alongside carcinoid tumours, which are a type of similar cancer that grows much slower. Because of that, Karlitz said that previous studies may have downplayed cancer results that were farther along in the stage of disease.
“Rectal carcinoids are quite common and usually much less aggressive than rectal adenocarcinomas, so if you lump these together, it could make EOCRC appear less aggressive than it really is,” he explained.
Researchers say their results back up recent changes that suggest screening for this cancer begins younger.
The U.S. Preventive Services Task Force announced in May 2021 that they were recommending that screening now start at 45 years of age for colorectal cancer, instead of at 50.
“We hope that the results of our manuscript motivate people to get screened on time at age 45 when they become eligible,” Karlitz said. “However, many patients under age 45 will not be eligible for average-risk screening, so it is imperative that we stratify young individuals for early testing based on symptoms and family history.”
Canadian guidelines currently recommend that screening begins at age 50 for those who do not have a high risk for colorectal cancer, according to the Canadian Task Force on Preventive Health Care. High risk includes having a family history of colorectal cancer, their website stated.
Karlitz added that the research also highlights some groups which could benefit from targeted screening and support.
“We need to place additional focus on racial subgroups that have an increased tendency to present with distant-stage disease, including the youngest non-Hispanic Black and Hispanic populations, to reverse these trends,” he said.