1277 A Closed-Loop Audit of the use of qFIT in Symptomatic “Two Week Wait” referrals in Somerset Foundation Trust

Introduction Quantitative faecal immunochemical test (qFIT) is recommended as the replacement test for faecal occult blood testing by NICE. We audited qFIT use in two week-wait (2WW) referrals in Somerset Foundation Trust (SFT) following its introduction in 2019. Method Following qFIT being made available to general practitioners, all 2WW referrals received before (July 2019) and after (December 2019) the introduction of the new 2WW referral form were reviewed. Electronic patient records were analysed to determine investigations performed and if a diagnosis of cancer was made. Results July 2019: 288 2WW referrals with 74 patients eligible for qFIT – only 7 of these underwent qFIT; total of 93 qFIT performed by GPs with 11 positive tests. December 2019: 222 2WW referrals with 18 patients eligible for qFIT – all of whom underwent qFIT; total of 155 qFIT performed by GPs with 18 positive (and 137 negative) tests. 1 patient with a positive qFIT was found to have colorectal malignancy (qFIT = 267 g/dL, investigation showed benign TVA). An increase in qFIT was observed over time, coinciding with a reduction in 2WW referrals, including reduction in patients who were qFIT eligible. The 2WW service identified 11 (3.8%) cases of colorectal cancer in July 2019 compared to 12 (5.4%) cases in December 2019, showing an increased pickup rate. Conclusions High proportions of 2WW referrals undergo investigation. The results of this audit highlight the utility of qFIT in screening 2WW referrals and reducing burden on the service, particularly where access to investigations is severely restricted due to coronavirus.

Estimation of overdiagnosis in colorectal cancer screening with sigmoidoscopy and faecal occult blood testing: comparison of simulation models

ObjectiveTo estimate overdiagnosis of colorectal cancer (CRC) for screening with sigmoidoscopy and faecal occult blood testing (FOBT).DesignSimulation study using data from randomised trials.SettingPrimary screening, UK, NorwayParticipants152 850 individuals from the Nottingham trial and 98 678 individuals from the Norwegian Colorectal Cancer Prevention (NORCCAP) trial.InterventionCRC screening.Outcome measureWe estimated overdiagnosis using long-term data from two randomised trials: the Nottingham trial comparing FOBT screening every other year to no-screening, and the NORCCAP trial comparing once-only sigmoidoscopy screening to no-screening. To estimate the natural growth of adenomas to CRC, we used the following microsimulation models: (i) the Microsimulation Screening Analysis; (ii) the CRC Simulated Population model for Incidence and Natural history; (iii) the Simulation Model of Colorectal Cancer; (iv) a model derived by the German Cancer Research Center. We defined overdiagnosed cancers as the difference between the observed number of CRCs in the no-screening arm and the expected number of cancers in screening arm (sum of observed and prevented by adenoma removal). The amount of overdiagnosis is defined as the number of overdiagnosed cancers over the number of cancers observed in the no-screening arm.ResultsOverdiagnosis estimates were highly dependent on model assumptions. For FOBT screening with 2354 cancers observed in control arm, four out of five models predicted overdiagnosis, range 2.0% (2400 cancers expected in screening) to 7.6% (2533 cancers expected in screening). For sigmoidoscopy screening with 452 cancers observed in control arm, all models predicted overdiagnosis, range 25.2% (566 cancers expected in screening) to 128.1% (1031 cancers expected in screening).ConclusionsThe amount of overdiagnosis estimated based on the microsimulation models varied substantially. Microsimulation models may not give reliable estimates of the preventive effect of adenoma removal, and should be used with caution to inform guidelines.

Transition to quantitative faecal immunochemical testing from guaiac faecal occult blood testing in a fully rolled-out population-based national bowel screening programme

ObjectiveFaecal immunochemical tests (FIT) are replacing guaiac faecal occult blood tests (FOBT) in colorectal cancer (CRC) screening. Data from the first year of FIT screening were compared with those from FOBT screening and assumptions based on a pilot evaluation of FIT.DesignData on uptake, positivity, positive predictive value (PPV) for CRC and higher-risk adenoma from participants in the first year of the FIT-based Scottish Bowel Screening Programme (n=919 665), with a threshold of 80 µg Hb/g faeces, were compared with those from the penultimate year of the FOBT-based programme (n=862 165) and those from the FIT evaluation (n=66 225).ResultsOverall, uptake of FIT was 63.9% compared with 56.4% for FOBT. Positivity was 3.1% and 2.2% with FIT and FOBT; increases were seen in both sexes, and across age range and deprivation. More CRC and adenomas were detected by FIT, but the PPV for CRC was less (5.2% with FIT and 6.4% with FOBT). However, for higher-risk adenoma, PPV was greater with FIT (24.3% with FIT and 19.3% with FOBT). In the previous FIT evaluation, uptake was 58.5% with FIT compared with 54.0% with FOBT; positivity was 2.5% with FIT and 2.0% with FOBT.ConclusionTransition to FIT from FOBT produced higher uptake and positivity with lower PPV for CRC and higher PPV for adenoma. The FIT pilot evaluation underestimated uptake and positivity. Introducing FIT at the same threshold as the evaluation caused a 67.2% increase in colonoscopy demand instead of a predicted 10%.

Faecal occult blood testing (FOBT)-based colorectal cancer screening trends and predictors of non-use: findings from the South Australian setting and implications for increasing FOBT uptake

Objective The present study used data from three South Australian population health surveys to examine trends in knowledge, recent use and reasons for use or non-use of faecal occult blood testing (FOBT) for colorectal cancer (CRC) screening from 2011 to 2014. Screening awareness and demographic factors related to non-use were also examined. Methods FOBT trends were examined for respondents aged 50–75 years across survey years (n ~ 1000). Logistic regression analyses were undertaken to determine predictors of non-use and reasons for non-use of FOBT based on latest data. Results The proportion of respondents reporting recent FOBT use has trended up, whereas the proportion reporting non-use has trended down. Awareness of screening recommendations has increased. Respondents who were aware of screening recommendations and those aged 65–69 years were significantly less likely to report non-use. The most commonly reported reasons for FOBT use were as part the national screening program or routine examination, whereas reasons for non-use were not having symptoms and doctor not advising to have the test. Conclusions FOBT screening trends are indicative of the positive effect of the continued expansion of the national screening program. FOBT uptake may be increased by addressing salient barriers, as indicated by persisting reasons for non-use of FOBT. What is known about the topic? Australia has one of the highest age-standardised incidence rates of CRC (or bowel cancer) in the world. Population screening using non-invasive stool-based FOBT was implemented in Australia in 2006 with the introduction of the National Bowel Cancer Screening Program (NBCSP). To date, the NBCSP has been extended to only a small proportion of the target population and FOBT screening rates remain well below desired levels to effect changes in CRC outcomes at the population level. There is a recognised need for more robust data on CRC screening practices to inform interventions aimed at increasing FOBT uptake, beyond the scope of the NBCSP. What does this paper add? The study provides valuable insights into trends of FOBT screening indicators over time in the South Australia, drawing on data from population state health surveys undertaken from 2011 to 2014. A particular advantage of the dataset was that it included data on reasons for use and non-use of FOBT. These data are not routinely assessed in population-level studies of FOBT uptake, although such information would be beneficial for tracking implementation of the national program and identifying salient barriers to FOBT uptake in low-participation groups. Thus, the study also describes factors related to non-use and reasons for non-use of FOBT among the target population for CRC screening. What are the implications for practitioners? Results suggest that there have been considerable shifts in community knowledge and FOBT screening participation rates from 2011 to 2014, reflecting the positive effect of the NBCSP. Reliance on physician recommendation to screen, as well as knowledge deficits related to screening frequency and the perceived relevance of screening remain prominent barriers to FOBT uptake. Recommendations for increasing FOBT uptake are made in view of salient barriers and identified segments of the population less likely to report FOBT use.

The development of an artificial stool usable for the surveillance of faecal haemoglobin testing

Background Faecal occult blood testing is an important diagnostic tool for the detection of colorectal cancer. However, it has not been standardized due to the absence of suitable specimens for surveillance. Methods We developed a ready-to-use artificial stool made from rice flour. This new artificial stool homogeneously contains not only human haemoglobin A0 (HbA0) but also glycerol as an internal standard material. After the collection of the artificial stool into a buffer, the haemoglobin concentration in dispersed solution was measured using a method based on the peroxidase like activity of haemoglobin. The glycerol concentration was measured using a commercially available triglyceride measurement kit. Results With regard to the haemoglobin stability, the decrease in the level of human haemoglobin in the artificial stool was <2% when it was stored at −80℃ for four months, −20℃ for two weeks, and 5℃ for two days. The artificial stool was easily collected with the collecting tubes of a commercially available faecal haemoglobin test kit. The weight of the collected artificial stool could be calculated by measuring the concentration of glycerol in the extracting solution of the collected stool sample. The haemoglobin concentrations could be adjusted based on their collection weights. Conclusions The artificial stool has a paste-like consistency and contains both haemoglobin and glycerol homogeneously. Furthermore, the measured haemoglobin concentration could be determined based on the collected stool weight, which was directly related to the glycerol concentration. These features make it a useful material for the surveillance of faecal occult blood testing.