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. The health care sector is responsible for over 4% of the global carbon footprint. The environmental impact can be reduced by prioritizing lower-carbon options when there are multiple choices available, as with average-risk colorectal cancer (CRC) screening. We used modeling to compare the impact of 2 commonly used CRC screening methods: colonoscopy and the multi-target stool DNA (mt-sDNA) test. Resource use was calculated, including waste and energy consumption from screening, patient travel, and test kit shipping. The estimated carbon-equivalent emissions for screening colonoscopy were 59% higher than for mt-sDNA, and most emissions from mt-sDNA were from follow-up colonoscopy after a positive test result. The reduced environmental impact of mt-sDNA screening as compared with colonoscopy is 1 factor that can be considered when choosing among guideline-recommended CRC screening options. The environmental impact of colorectal cancer screening with noninvasive multi-target stool DNA (mt-sDNA) was compared with colonoscopy. There were 59% more carbon-equivalent emissions with a colonoscopy screening strategy as compared with mt-sDNA. Most emissions incurred by the mt-sDNA strategy were attributable to follow-up colonoscopy after a positive mt-sDNA result. The results demonstrate that the environmental impact of colorectal cancer screening varies significantly across guideline-endorsed options. Environmental considerations could serve as an additional criterion for patients choosing a screening modality.