Lowering the colorectal cancer screening age improves predicted outcomes in a microsimulation model

Area of Science:

• Oncology
• Preventive Medicine
• Health Services Research

Background:

• Colorectal cancer (CRC) incidence is rising in younger populations.
• Current guidelines recommend CRC screening initiation at age 50 for average-risk individuals.
• There is a growing trend to lower the recommended screening age to 45.

Purpose of the Study:

• To model the impact of lowering CRC screening initiation age from 50 to 45 years.
• To compare triennial multi-target stool DNA (mt-sDNA) and annual fecal immunochemical test (FIT) screening strategies.
• To incorporate theoretical and reported adherence rates into the screening models.

Main Methods:

• Simulated screening strategies for individuals aged 40 without CRC.
• Modeled screening from ages 50-75 versus 45-75.
• Calculated CRC incidence, mortality, and life-years gained (LYG) using perfect (100%) and reported adherence rates (71% mt-sDNA; 43% FIT).

Main Results:

• Lowering screening initiation to age 45 increased predicted life-years gained (LYG) by 22.2-24.4 per 1000 individuals.
• Initiation at age 45 reduced CRC cases and deaths compared to age 50, particularly with reported adherence.
• With reported adherence, mt-sDNA averted more CRC cases (8.6) and deaths (3.3) per 1000 individuals than FIT.

Conclusions:

• Lowering CRC screening initiation age to 45 improves estimated screening outcomes.
• Triennial mt-sDNA screening demonstrates greater benefits than annual FIT screening when reported adherence rates are considered.
• These findings support the potential benefits of earlier CRC screening and highlight differences in screening test effectiveness based on adherence.