Environmental impact of colorectal cancer screening with colonoscopy and multi-target stool DNA (mt-sDNA) testing

The substantial carbon footprint imparted by medical services warrants increased attention to their environmental impact. National guideline organizations such as the US Preventive Services Task Force (USPSTF) recommend multiple modalities for average-risk colorectal cancer (CRC) screening with varying resource intensity. The aim of this study was to quantify the environmental burden for 2 of the most used CRC screening modalities, colonoscopy and the multi-target stool DNA (mt-sDNA) test. A validated CRC microsimulation model was used to estimate the number of screening and follow-up tests for a cohort of 1 million average-risk individuals who underwent screening between ages 45 and 75. Component resources used for mt-sDNA, including waste products, energy, and transportation for colonoscopy and mt-sDNA, were collected from January 1, 2023, to January 1, 2024, and converted to carbon-equivalent emissions. Resources used for colonoscopy were captured from the literature. Resources devoted to screening colonoscopy were substantially (59%) higher than those to mt-sDNA, even when including follow-up colonoscopy. Of note, follow-up colonoscopy accounted for the majority (64%) of total emissions for the mt-sDNA screening strategy. Compared with colonoscopy screening, mt-sDNA substantially reduces the carbon emissions attributable to population-level CRC screening. Environmental impact should be included as a factor when choosing among guideline-recommended CRC screening strategies.