BETHESDA, MD — Rates of colorectal cancer have been rising in younger patients since the mid-1980s, even as rates have fallen in individuals over age 50, according to the American Cancer Society.

An international team of researchers including Chunqiao Tian, PhD, of the Uniformed Services University of Health Sciences and Walter Reed National Military Medical Center, both in Bethesda, MD, sought to characterize the age, race, stage, region, and tumor location in younger patients with colorectal cancer compared to older patients. They also investigated health disparities in younger patients that may affect the rate of CRC.

They presented their results at the 2020 American Society of Clinical Oncologists Annual Meeting held May 29-31.1

The researchers pulled data from the U.S. Cancer Statistics for patients diagnosed between 2001 and 2014 with CRC. 

During the period studied, they found 1,886,441 cases of CRC and an overall downward trend. The incidence rate declined from 52.9 per 100,000 in 2001 to 35.22 in 2014. The Northeast had the highest age-adjusted incidence (45.26 per 100,000), while the South accounted for more than one-third of all diagnoses.

Younger patients were more likely to be diagnosed with metastatic disease (25.8%) than patients over age 50; they also had higher rates of sigmoid and rectal cancers,64.3% vs 45.7% for older patients.

Among the 170,244 CRC patients under age 50, 53.4% were men and 46.6% were women. In this group, the age-specific incidence rose from 5.63 to 6.48 per 100,000 over the study period. The annual percentage change rose from an increase of 1.24% from 2001 to 2008 to an increase of 2.55% each year from 2012 to 2014.

Within the under-50 group, the age-specific incidence rose substantially with each decade. Patients up to age 29 had an incidence of 0.41, while those 30 to 39 had an incidence of 6.08, and those 40 to 49 had an incidence of 21.09.

Under age 50, blacks had the highest age specific incidence of CRC at 7.16 per 100,000 vs 6.43 for Asians, 6.07 for whites, and 4.76 per 100,000 for Hispanics.

The researchers recommended additional studies to determine how to improve colonoscopy or sigmoidoscopy screening for younger patients at risk of developing colorectal cancer.

  1. Abel MK, Liao C-I, Van Loon K, Tian C, Darcy KM, Mann AK, Kapp DS, Chan JK. “The increasing incidence of colorectal cancer in younger patients in the United States: Who, what, when, and where?” Abstract 1573. Poster 65. 2020 ASCO Annual Meeting. May 29-31, 2020.