Screening for colorectal cancer in defunctioned colons

Objectives: Population-based colorectal (bowel) cancer screening using faecal occult blood tests leads to a reduction in cause-specific mortality. However, in people where the colon is defunctioned, the use of standard faecal occult blood test is not appropriate. The aim of this study was to examine the current trends of clinical practice for colorectal cancer screening in people with defunctioned colons.Methods: An online survey was performed using SurveyMonkey. All members of the Association of Coloproctology of Great Britain and Ireland were invited by email to participate. Reminders were sent to non-responders and partial responders till six weeks. All responses were included in our analysis.Results: Of the 206 (34.59%) questionnaires completed, all questions were answered in 110 (55.8%). Among responders, 94 (85.4%) were colorectal consultant surgeons, 72% had worked in their current capacity for more than five years, and 105 (50.9%) had encountered colorectal cancer in defunctioned colons during their career. Some 72.2% of responders stated that a screening test for colorectal cancer in patients with defunctioned colons was currently not offered, or that they did not know whether or not it was offered in their area.Conclusions: Bowel screening in the United Kingdom is currently not offered to 72.2% of the age appropriate population with defunctioned colons. Among responding colorectal surgeons, 50% had encountered colorectal cancer in such patients. There is considerable variability in clinical practice regarding the optimal age for onset of screening, time interval, and the optimal modality to offer for screening in such cases.</p

Inke Näthke:The ABCs of APC

Näthke investigates the many functions of adenomatous polyposis coli protein and its contribution to human disease

Scottish Bowel Screening Programme colonoscopy quality – scope for improvement?

Aim: The delivery of the Scottish Bowel Screening Programme (SBoSP) is rooted in the provision of a high quality, effective and participant-centred service. Safe and effective colonoscopy forms an integral part of the process. Additional accreditation as part of a multi-faceted programme for participating colonoscopists, as in England, does not exist in Scotland. This study aimed to describe the quality of colonoscopy in the SBoSP and compare this to the English national screening standards. Methods: Data were collected from the SBoSP between 2007 and 2014. End-points for analysis were caecal intubation, cancer, polyp and adenoma detection, and complications. Overall results were compared with 2012 published English national standards for screening and outcomes from 2006 to 2009. Results: During the study period 53 332 participants attended for colonoscopy. The colonoscopy completion rate was 95.6% overall. The mean cancer detection rate was 7.1%, the polyp detection rate was 45.7% and the adenoma detection rate was 35.5%. The overall complication rate was 0.47%. Conclusion: Colonoscopy quality in the SBoSP has exceeded the standard set for screening colonoscopy in England, despite not adopting a multi-faceted programme for screening colonoscopy. However, the overall adenoma detection rate in Scotland was 9.1% lower than that in England which has implications for colonoscopy quality and may have an impact on cancer prevention rates, a key aim of the SBoSP.</p

Application of NICE guideline NG12 to the initial assessment of patients with lower gastrointestinal symptoms:not FIT for purpose?

Background: The National Institute for Health and Care Excellence (NICE) published NG12 in 2015. The referral criteria for suspected colorectal cancer (CRC) caused controversy, because tests for occult blood in faeces were recommended. Faecal immunochemical tests for haemoglobin (FIT), which estimate faecal haemoglobin concentrations (f-Hb), might more than fulfil the intentions. Our aim was to compare the utility of f-Hb as the initial investigation with the NICE NG12 symptom-based guidelines.Methods: Data from three studies were included. Patients had sex, age, symptoms, f-Hb and colonoscopy and histology data recorded. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of f-Hb and NG12 were calculated for all significant colorectal disease (SCD: CRC, higher risk adenoma and inflammatory bowel disease). Overall diagnostic accuracy was also estimated by the area under the receiver operating characteristic curve (AUC).Results: A total of 1514 patients were included. At a cut-off of ≥10  µg Hb/g faeces, the sensitivity of f-Hb for CRC was 93.3% (95% confidence interval (CI): 80.7-98.3) with NPV of 99.7% (95%CI: 99.2-99.9). The sensitivity and NPV for SCD were 63.2% (95%CI: 56.6-69.4) and 96.0% (95%CI: 91.4-94.4), respectively. The NG12 sensitivity and NPV for SCD were 58.4% (95%CI: 51.8-64.8) and 87.6% (95%CI: 85.0-89.8), respectively. The AUC for CRC was 0.85 (95% CI: 0.87-0.90) for f-Hb versus 0.65 (95%CI: 0.58-0.73) for NG12 ( P &lt; 0.005). For SCD, the AUC was 0.73 (95%CI: 0.69-0.77) for f-Hb versus 0.56 (95%CI: 0.52-0.60) for NG12 ( P &lt; 0.0005).Conclusion: f-Hb provides a good rule-out test for SCD and has significantly higher overall diagnostic accuracy than NG12.</p

Participation in bowel screening among men attending abdominal aortic aneurysm screening

Background: Uptake of population-based screening for colorectal cancer in Scotland is around 55 per cent. Abdominal aortic aneurysm (AAA) screening has recently been introduced for men aged 65 years and the reported uptake is 78 per cent. The aim was to determine the impact of a brief intervention on bowel screening in men who attended AAA screening, but previously failed to complete bowel screening.Methods: Men invited for AAA screening between September 2015 and March 2016 within NHS Tayside were included. Attendees who had not responded to their latest bowel screening invitation were seen by a colorectal cancer clinical nurse specialist. Reasons for not completing the faecal occult blood test (FOBT) were recorded; brief information on colorectal cancer screening was communicated, and participants were offered a further invitation to complete a FOBT. Those who responded positively were sent a further FOBT from the Scottish Bowel Screening Centre. Subsequent return of a completed FOBT within 6 months was recorded. Results: A total of 556 men were invited for AAA screening, of whom 38⋅1 per cent had not completed a recent FOBT. The primary reason stated for not participating was the time taken to complete the test or forgetting it (35⋅1 per cent). Other reasons included: lack of motivation (23⋅4 per cent), confusion regarding the aim of screening (16⋅2 per cent), disgust (19⋅8 per cent), fear (6⋅3 per cent) and other health problems (9⋅9 per cent). Following discussion, 81⋅1 per cent agreed to complete the FOBT and 49 per cent subsequently returned the test. Conclusion: A substantial proportion of previous bowel screening non-responders subsequently returned a completed FOBT following a brief intervention with a nurse specialist. Attendance at non-bowel screening appointments may provide a valuable opportunity to improve bowel screening uptake

Faecal immunochemical tests for haemoglobin (FIT) in the assessment of patients with lower abdominal symptoms:current controversies

Faecal immunochemical tests for haemoglobin (FIT), as an adjunct to clinical information, assist in the triage of patients presenting in primary care with lower abdominal symptoms. Controversy remains regarding whether and which qualitative and quantitative FIT can be used, which groups of patients would benefit most from FIT, whether FIT should be done in primary and/or secondary care, and how FIT should be incorporated into diagnostic pathways. Controversy also exists as to the optimum cut-off used for referral for colonoscopy. A single sample of faeces may be sufficient. Reporting of results requires consideration. FIT provide a good rule in test for colorectal cancer and a good rule out test for significant bowel disease, but robust safety-netting is required for patients with negative results and ongoing symptoms. Risk scoring models have been developed, but their value is unclear as yet. Further evaluation of these topics is required to inform good practice.</p

Variational Autoencoders for Feature Exploration and Malignancy Prediction of Lung Lesions

Lung cancer is responsible for 21% of cancer deaths in the UK and five-year survival rates are heavily influenced by the stage the cancer was identified at. Recent studies have demonstrated the capability of AI methods for accurate and early diagnosis of lung cancer from routine scans. However, this evidence has not translated into clinical practice with one barrier being a lack of interpretable models. This study investigates the application Variational Autoencoders (VAEs), a type of generative AI model, to lung cancer lesions. Proposed models were trained on lesions extracted from 3D CT scans in the LIDC-IDRI public dataset. Latent vector representations of 2D slices produced by the VAEs were explored through clustering to justify their quality and used in an MLP classifier model for lung cancer diagnosis, the best model achieved state-of-the-art metrics of AUC 0.98 and 93.1% accuracy. Cluster analysis shows the VAE latent space separates the dataset of malignant and benign lesions based on meaningful feature components including tumour size, shape, patient and malignancy class. We also include a comparative analysis of the standard Gaussian VAE (GVAE) and the more recent Dirichlet VAE (DirVAE), which replaces the prior with a Dirichlet distribution to encourage a more explainable latent space with disentangled feature representation. Finally, we demonstrate the potential for latent space traversals corresponding to clinically meaningful feature changes.Comment: 10 pages (main paper), 5 pages (references), 5 figures, 2 tables, work accepted for BMVC 202

Effect of the addition of different waste carbonaceous materials on coal gasification in CO2 atmosphere

YesIn order to evaluate the feasibility of using CO2 as a gasifying agent in the conversion of carbonaceous materials to syngas, gasification characteristics of coal, a suite of waste carbonaceous materials, and their blends were studied by using a thermogravimetric analyser (TGA). The results showed that CO2 gasification of polystyrene completed at 470 °C, which was lower than those of other carbonaceous materials. This behaviour was attributed to the high volatile content coupled with its unique thermal degradation properties. It was found that the initial decomposition temperature of blends decreased with the increasing amount of waste carbonaceous materials in the blends. In this study, results demonstrated that CO2 co-gasification process was enhanced as a direct consequence of interactions between coal and carbonaceous materials in the blends. The intensity and temperature of occurrence of these interactions were influenced by the chemical properties and composition of the carbonaceous materials in the blends. The strongest interactions were observed in coal/polystyrene blend at the devolatilisation stage as indicated by the highest value of Root Mean Square Interaction Index (RMSII), which was due to the highly reactive nature of polystyrene. On the other hand, coal/oat straw blend showed the highest interactions at char gasification stage. The catalytic effect of alkali metals and other minerals in oat straw, such as CaO, K2O, and Fe2O3, contributed to these strong interactions. The overall CO2 gasification of coal was enhanced via the addition of polystyrene and oat straw

An advanced biomass gasification technology with integrated catalytic hot gas cleaning. Part III: Effects of inorganic species in char on the reforming of tars from wood and agricultural wastes

Char is used directly as a catalyst for the catalytic reforming of tar during gasification. Experiments have been carried out to examine the effects of inorganics in char as a catalyst for the catalytic reforming of tar during the gasification of mallee wood, corn stalk and wheat straw in a pilot plant. The char catalyst was prepared from the pyrolysis of mallee wood at a fast heating rate. The catalytic activities of char and acid-washed char for tar reforming were compared under otherwise identical gasification conditions. For all biomass feedstocks tested for gasification, the tar contents in product gas could be drastically reduced by the catalyst, reaching a tar concentration level well below 100 mg/N m3. The acid-washed char also showed profound activity for tar reforming although its catalytic activity was definitely lower than the raw char. Both catalysts could effectively reform the aromatic ring systems (especially large aromatic ring systems with three or more fused benzene rings) in tars as is revealed using UV-fluorescence spectroscopy. The char itself was also partially gasified. After being used as a catalyst, the condensation of the aromatic rings and the accumulation of inorganic species led to drastic changes in char reactivity with O2 at 400 °C. The inorganic species in char tended to enhance the formation of H2 and CO during the reforming reactions in the catalytic reactor

Formation of nascent char structure during the fast pyrolysis of mallee wood and low-rank coals

The structural evolution of nascent chars during the fast pyrolysis of a wood and two low-rank coals was investigated in this study. Western Australian Collie sub-bituminous coal, Victorian Loy Yang brown coal and Western Australian mallee wood were pyrolysed in a wire-mesh reactor that is capable of providing rapid heating rates (up to 5000 K s−1) and accurate holding time (in increments of 10 ms) at peak temperature. FT-Raman spectroscopy was used to characterise the key structural features of raw fuels and nascent chars. The combined use of a wire-mesh reactor and a FT-Raman spectroscopy has given insights into the structural transformation from coal/biomass to nascent chars. There were insignificant changes in the aromatic ring systems of two coals during the initial fast heating from room temperature to 600 °C. During holding at 600 °C, the changes that occurred in ring systems for the three fuels were different. Mallee wood and Loy Yang coal underwent more changes than Collie coal. In addition, mallee wood had ring condensation during holding at 600 °C up to 30s. However, little growth in large aromatic rings of two coals was observed during holding at 600 °C up to 50 s