Lay summary
New Zealand (NZ) has one of the highest rates of colorectal cancer (CRC) in the world, and it is increasing in younger people and in Māori, making this both a health and equity issue. The microbiome has been strongly implicated in CRC, and we will harness our knowledge of the microbiome to develop a completely novel application of liquid biopsies, circulating bacterial DNA, as an early detection tool for metastasis in CRC. Our study findings have the potential to revolutionise cancer management, and reduce overall mortality from CRC.