Implementation of BSG/ACPGBI/PHE polypectomy surveillance guidelines safely reduces the burden of surveillance in a screening cohort: a virtual model study

Objective To evaluate the impact of British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland/Public Health England (BSG/ACPGBI/PHE) 2019 polypectomy surveillance guidelines within a national faecal immunochemical test-based bowel cancer screening (BS) cohort on surveillance activity and detection of pathology by retrospective virtual application.Design A retrospective review of BS colonoscopies performed in 2015–2016 with 5 years prospective follow-up in single institution. Index colonoscopies were selected. Incomplete colonoscopies were excluded. Histology of all resected polyps was reviewed. Surveillance intervals were calculated according to BSG/ACPGBI/PHE 2019 guidelines and compared with pre-existing ‘European Guidelines for Quality Assurance in Colorectal Cancer Screening and Diagnosis’ (EUQA 2013). Total number of colonoscopies deferred by virtual implementation of BSG/ACPGBI/PHE 2019 guidelines were calculated. Pathology identified on procedures that would have been deferred was reviewed.Results Total number of index BS colonoscopies performed in 2015–2016 inclusive was 890. 115 were excluded (22 no caecal intubation, 51 inadequate bowel preparation, 56 incomplete polyp clearance). N=509 colonoscopies were scheduled within a 5-year interval following index colonoscopy surveillance rounds based on EUQA guidelines. Overall, volume of surveillance was significantly reduced with retrospective application of BSG/ACPGBI/PHE 2019 guidelines (n=221, p<0.0001). No cancers were detected within the ‘potentially deferred’ procedures who attended for follow-up (n=330) with high-risk findings found in<10% (n=30) of colonoscopies within the BSG/ACPGBI/PHE cohort.Conclusion BSG/ACPGBI/PHE 2019 guidelines safely reduce the burden of colonoscopy demand with acceptable pathology findings on deferred colonoscopies

Climate and soils together regulate photosynthetic carbon isotope discrimination within C<inf>3</inf> plants worldwide

© 2018 John Wiley & Sons Ltd Aim: Within C3 plants, photosynthesis is a balance between CO2 supply from the atmosphere via stomata and demand by enzymes within chloroplasts. This process is dynamic and a complex but crucial aspect of photosynthesis. We sought to understand the spatial pattern in CO2 supply–demand balance on a global scale, via analysis of stable isotopes of carbon within leaves (Δ13C), which provide an integrative record of CO2 drawdown during photosynthesis. LocationGlobal. Time period1951–2011. Major taxa studiedVascular plants. Methods: We assembled a database of leaf carbon isotope ratios containing 3,979 species–site combinations from across the globe, including 3,645 for C3 species. We examined a wide array of potential climate and soil drivers of variation in Δ13C. Results: The strongest drivers of carbon isotope discrimination at the global scale included atmospheric pressure, potential evapotranspiration and soil pH, which explained 44% of the variation in Δ13C. Addition of eight more climate and soil variables (each explaining small but highly significant amounts of variation) increased the explained variation to 60%. On top of this, the largest plant trait effect was leaf nitrogen per area, which explained 11% of Δ13C variation. Main conclusions: By considering variation in Δ13C at a considerably larger scale than previously, we were able to identify and quantify key drivers in CO2 supply–demand balance previously unacknowledged. Of special note is the key role of soil properties, with greater discrimination on low-pH and high-silt soils. Unlike other plant traits, which show typically wide variation within sets of coexisting species, the global pattern in carbon stable isotope ratios is much more conservative; there is relatively narrow variation in time-integrated CO2 concentrations at the site of carboxylation among plants in a given soil and climate