Uptake of colorectal cancer (CRC) screening among people in their mid to late 40s in the United States increased significantly in the year following the American Cancer Society’s (ACS’s) lowering of the recommended age for screening, a new study has found.

In 2018, the ACS lowered the recommended starting age for CRC screening from 50 to 45 years.

In the year that followed, CRC screening rates increased significantly among adults aged 45–49 years, but remained stable for those in their 50s.

The finding was published online December 18 in Cancer.

The authors, led by Stacey Fedewa, PhD, an epidemiologist at the ACS, comment that the new guidelines and the “accompanying scientific and lay media attention may have raised provider and patient awareness of asymptomatic and symptomatic testing for CRC.”

They point out that “similar abrupt changes in screening following release of updated guidelines have been reported for prostate and breast cancer, as have short-term gains in CRC screening following media campaigns.”

However, Fedewa noted that “it is unknown whether the recent accelerating CRC screening rates among people 45–49 years will be sustained.

“Commercial health insurers are only required to cover average-risk screening beginning at age 50, following recommendations from the US Preventive Services Task Force. Also, it’s possible those who quickly adopted updated guidelines may have been those at increased risk,” she said in a statement.

Increase in Incidence in Younger Adults

Fedewa and colleagues explain that the ACS lowered the age for average-risk CRC screening from 50 to 45 years after reports of a dramatic rise in the incidence of CRC in younger adults.

To determine whether it had an impact on screening among people in the targeted age group, they examined data on persons aged 45–59 years who responded to the 2018 National Health Interview Survey.

They included 5800 individuals; 1796 persons were aged 45–49 years, 1877 were aged 50–54 years, and 2127 were aged 55–59 years.

Just over half of the respondents were women, approximately two thirds were non-Hispanic whites, and around three quarters were privately insured.

During 2018, the rate of CRC screening rose among people aged 45–49 years from 4.8% in the first quarter (Q1) to 6.6% in Q2, 8.8% in Q3, and 11.7% in Q4.

The team calculates that screening rates in Q3 were 4.1% higher than in Q1, and rates in Q4 were 7.0% higher. This equates to 226,656 people being screened in Q1 vs 592,531 in Q4.

In contrast, there was no increase in CRC screening among people in their 50s. As a consequence, increases in screening rates were significantly higher among people aged 40–49 years than among those aged 50–54 and 55–59 years.