Early screening linked to spike in early-stage colon cancer diagnoses

By Dr. Liji Thomas, MDReviewed by Lauren HardakerAug 7 2025

New screening guidelines may save lives: Researchers find major rise in early-stage colorectal cancers among newly eligible 45–49-year-olds.

Study: Colorectal Cancer Incidence in US Adults After Recommendations for Earlier Screening. Image credit: Kateryna Kon/Shutterstock.com

Colorectal cancer (CRC) is among the major killers in the United States. The recommended screening age for CRC was recently lowered to 45 years, followed by a rise in screening rates. This coincided with a higher CRC incidence. A recent study in JAMA examined whether this resulted from successful screening or reflected an actual increase in disease incidence.

Introduction

There were, on average, 37 new CRC cases per 100,000 people each year, with an annual mortality of ~13 per 100,000, over the period 2018-2022. 

While CRC screening in the USA used to begin at 50 years, the American Cancer Society and the US Preventive Services Task Force (USPSTF) recommended that the screening threshold be reduced to 45 years in 2018 and 2021, respectively. Following these recommendations, survey and insurance claims data indicated increased CRC screening activity among adults between 45 and 49 years old in 2018-2022, along with an increase in the number of CRC diagnoses.

The current study aimed to understand the reason for this uptick in CRC incidence. The investigators examined CRC cases among adults between 20 and 54 years of age from 2004 to 2022.

Study findings

The records revealed 219,373 cases of CRC, with a mean age of 47. From 2004 onwards, the incidence of CRC increased steadily by 1.6% each year among those aged 20 to 39. In the group aged 40 to 44, the increase was 2.6%.

For adults between 45 and 49, the annual incidence rose by 1.1% until 2019 but rose rapidly by 12% each year from 2019 to 2022. Among those aged 50 to 54, it increased by 2.0%.

Thus, all groups showed a stable increase in incidence except in the newly screening-eligible group. In this group, most new tumors detected were local-stage tumors, with an annual percentage change of ~22%. The incidence of localized tumors increased by 25% in 2021 relative to 2019, and by 50% in 2022 compared to 2021. This contrasts with the stable rates observed from 2004 to 2019.

Stratifying by location, colon cancer rates showed an annual percentage change of ~18.8% during 2019 to 2022, vs. 25.1% for rectal cancer. Again, both spikes came after a period of either stable or decreasing incidence.

In all other age groups, the rates of local-stage cancers failed to show this spike. In the group aged 20 to 39, localized cancer incidence remained stable, while in the other two groups, it had much smaller increases (ranging from 2.5% to 3.1% annually).

Advanced cancer rates showed an increase of 1.7% to 2.9% per year during the period beginning in 2004 in those below 45 years, but the last ten years witnessed a sharper increase among those aged 45 to 54 years.

It is important to note that 2020 data were excluded from trend analyses due to pandemic-related disruptions in cancer diagnoses.

Conclusions

The study shows that after remaining stable for about 15 years, local CRC rates increased sharply in adults between 45 and 49 years during 2019 to 2022. The most significant relative increase was from 2021 to 2022, by 50%. In contrast, advanced cancer diagnoses remained stable in the same age group.

The increase in CRC diagnoses in adults between 45 and 49 might reflect increased diagnoses in 2021 after missing opportunities because of the pandemic. While this might be one explanation, the USPSTF did not recommend lowering the screening age until 2021. Moreover, the increase reflected only early-stage disease in the age group that was freshly brought under the screening umbrella and became steeper in 2022.

A more plausible explanation could be that this “likely reflects diagnosis of prevalent asymptomatic cancer through first-time screening due to recommendations for adults to begin screening at age 45 years instead of 50 years.”

However, the study authors caution that only four years of post-recommendation data are currently available, and the impact of the pandemic may still confound results. The findings indicate that increased early-stage CRC detection is a promising result of screening adults for the disease at younger ages.

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