Increases in Early-Onset Colorectal Cancer Not Solely Due to Increased Screening

colon polyps, CRC, colorectal cancer
Investigators assessed whether the increase in early-onset colorectal cancer incidence is a product of increased colonoscopy screening or due to other factors.

Early-onset colorectal cancer (CRC) is on the rise and typically being diagnosed at an advanced-stage, with the largest increase in disease burden occurring in patients aged between 45 and 49 years, according to a study published in Gastroenterology.

Researchers conducted a retrospective study including members of Kaiser Permanente Northern California health plans aged 18 to 49 or 50 to 54 years from 1998 to 2018. Participants were followed from entry until the day before their 50th and 55th birthdays, respectively, a diagnosis with CRC, membership disenrollment, death, or the end of the study period. For each age group and year in the study period, CRC incidence, colonoscopy use, colonoscopy indication, and cancer stage at diagnosis were assessed. By using a cohort of the same population over time, investigators attempted to eliminate access to care as a contributing factor.

Over the study period, 5,982,616 individuals aged 18 to 49 years and 1,625,690 individuals aged 50 to 54 years were included. Among patients in the younger-adult cohort, 151,363 received a colonoscopy and 2280 received a new CRC diagnosis; in the older-adult cohort, 181,322 and 2259 patients received a colonoscopy and new CRC diagnosis, respectively.

Colonoscopy use increased by 6.6% annually in the younger-adult cohort, from 2.8 procedures per 1000 person-years (PY) in 1998 to 10.1 procedures per 1000 PY in 2018 (P <.001). The annual increase in the older-adult cohort was 7.4%, from 16.7 procedures per 1000 PY in 1998 to 70.0 procedures per 1000 PY in 2018 (P <.001).

In the younger-adult cohort, CRC incidence rates increased annually by 1.4%, from 6.0 cases per 100,000 PY in 1998 to 8.0 cases per 100,000 PY in 2018 (P <.001). Incidence rates also increased annually in the older-adult cohort by 2.2%, from 42.2 cases per 100,000 PY in 1998 to 65.1 cases per 100,000 PY in 2018 (P <.001).

Increases in CRC incidence among both groups were associated with colonoscopy use; however, the reasons for the rise in use differed between age groups. Among the younger-adult cohort, increased diagnoses of advanced-stage disease drove the increase in CRC incidence. About 65% of colonoscopies were performed for diagnostic purposes, indicating these procedures were done to investigate reported symptoms and were not simply a product of a lowered threshold for screening.

Increased diagnoses of early-stage disease drove the increase in CRC incidence among the older-adult cohort. These results are in concordance with the trend towards increased colonoscopy screenings in patients of more advanced age.  

“Thus, while increasing CRC incidence rates paralleled increases in colonoscopy use – the procedure by which CRC is typically diagnosed – the stark differences in colonoscopy indication and stage of disease at diagnosis support the conclusion that the rise in early-onset CRC is not solely an artifact of increasing colonoscopy use, but likely reflects a true increase in disease burden,” the researchers noted.

Investigators concluded that adhering to recent recommendations to begin screening for CRC in patients aged 45 rather than 50 years could potentially “substantially reduce the burden of early-onset CRC.”


Lee JK, Merchant SA, Jensen CD, Murphy CC, Udaltsova N, Corley DA. Rising early-onset colorectal cancer incidence is not an artifact of increased screening colonoscopy use in a large, diverse healthcare system. Gastroenterol. Published online September 20, 2021. doi: 10.1053/j.gastro.2021.09.034.