Recent colorectal cancer screening rates more than doubled among people ages 45 to 49 in the months after the release of updated American Cancer Society guidelines recommending screening in that age group, according to a study published in CANCER.

The increase in was unique to the 45 to 49 year-old age group according to the study.

In May 2018, the American Cancer Society (ACS) updated its colorectal cancer (CRC) screening guidelines, lowering the age to begin average-risk screening from 50 to 45 years, based on increasing incidence of early onset colorectal cancer and a favourable benefit-to-harm ratio.

Whether this change has influenced screening among people in their mid-to-late 40's is unknown.

To find out, investigators led by the ACS's Stacey Fedewa, PhD examined recent CRC screening patterns among adults ages 45 to 49 compared to those ages 50 to 59 in the United States.

They reviewed responses from about 5,800 people ages 45 to 59 participating in the 2018 National Health Interview Survey (NHIS), an in-person household survey.

Among people ages 45 to 49, past-year CRC screening rates rose from 4.8% in the first quarter (Q1) of 2018 to 6.6% in Q2, 8.8% in Q3, and 11.7% in Q4.

Compared to Q1, screening rates were 4.1% and 7.0% percentage-points higher in Q3 and Q4, respectively.

The estimated number of people ages 45 to 49 screened rose from 226,656 in Q1 of 2018 to 592,351 in Q4, a rise of 365,695.

Past-year CRC screening did not increase among people in their 50's.

The authors say the 2018 ACS guidelines and accompanying scientific and lay media attention may have raised provider and patient awareness of asymptomatic and symptomatic testing for CRC, noting 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.

"It is unknown whether the recent accelerating CRC screening rates among people 45-49 years will be sustained," said Dr Fedewa. "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."

Source: American Cancer Society