Bowel Screening Programme Research Articles

Polokalama Fekumi ki he Kanisā 'o e Halanga-me'atokoní-Ko e vakai 'a e Tongá: Tongan New Zealanders' views on how to ensure the National Bowel Cancer Screening Programme works well for the Tongan community.

The National Bowel Screening Programme (NBSP) fails to deliver screening equitably to Pacific New Zealanders. This research explored Tongan New Zealanders' experiences of participating in the NBSP and their views on ensuring the programme works well for the Tongan community. In 2021, we conducted two talanoa focus groups with Tongan New Zealanders who had participated in the NBSP (n=26), recruited through a Pacific provider in Auckland. Participants were aged 60 or more and were Tongan born. Interviews with four Pacific experts working in the NBSP were also undertaken. Their views on the NBSP were explored and analysed using thematic analysis. While the research participants valued the opportunity to participate in the NBSP, they had many valuable insights about strengthening it, as did the Pacific experts. Key was a by Tongan, for Tongan service run by Tongan providers, one based on Tongan models of health and health promotion, Tongan values and ways of working, and using the Tongan language, which empowers Tongans to take control of their health. This research demonstrates critical elements of an effective, culturally appropriate and empowering NBSP for Tongans led by Tongan providers. If these findings are enacted, more effective delivery of bowel screening to Tongans will likely be enabled, reducing inequity in participation between Tongans and other New Zealanders. What is required is courage and political will to shift power and resources to ensure equitable outcomes in the NBSP, not only for Tongans but for all Pacific peoples.

Repeat Faecal Immunochemical Testing for Colorectal Cancer Detection in Symptomatic and Screening Patients: A Systematic Review and Meta-Analysis.

Faecal immunochemical testing (FIT) is widely used in bowel screening programmes and assessing symptomatic patients for suspected colorectal cancer (CRC). The evidence for single test performance of FIT in both settings is considerable; however, the use of a repeat test to increase sensitivity remains uncertain. We aimed to review what increase in test positivity would be generated by additional FITs, whether a repeated FIT detects previously missed CRC and advanced colorectal neoplasia (ACRN), and to estimate the sensitivity of double-FIT strategies to diagnose CRC and ACRN. A systematic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) was performed using key search terms. Studies reporting the use of more than one FIT in the same screening round or planned assessment of a single symptomatic patient episode were included. Studies were categorised by the reported study population into asymptomatic, mixed (cohorts of combined asymptomatic, symptomatic, or high-risk surveillance), or symptomatic cohorts. A total of 68 studies were included for analysis (39 asymptomatic, 21 mixed, 7 symptomatic, and 1 study with discrete asymptomatic and symptomatic data). At a threshold of 10 µg Hb/g, the two-test positivity ranged between 8.1 and 34.5%, with an increase from the second test of 3-9.2 percentage points. Four out of five studies comparing one versus two tests for diagnosing CRC at 10 µg Hb/g identified additional cases with the second test, with a minimum of 50% reduction in missed CRC. At a threshold of 20 µg Hb/g, the second test increased the positivity by 1.3-6.7 percentage points, with a two-test positivity of between 5.1 and 25.0%. Using a threshold of 20 µg Hb/g, five out of seven studies had a 25% reduction in missed CRC. A meta-analysis estimated the double-FIT sensitivity at 10 µg Hb/g for CRC in mixed-risk and symptomatic cohorts to be 94% and 98%, respectively. Repeated use of FIT helps to diagnose more cases of CRC with a moderate increase in positivity. A double-FIT strategy at 10 µg Hb/g in mixed and symptomatic cohorts has a very high sensitivity for CRC.

Varying faecal immunochemical test positivity thresholds impacts colorectal cancer detection

Abstract Background Colorectal cancer (CRC) is screened for by the faecal immunochemical test (FIT) in Ireland. The FIT positivity threshold in Ireland is 45 micrograms (µg) of haemoglobin per gram (g) of stool. FIT positivity thresholds influence both demand for screening colonoscopies and CRC detection rates through screening. This study aimed to assess the impact of varying FIT positivity thresholds on CRC detection rates through screening in Ireland. Methods This study used data from BowelScreen - The National Bowel Screening Programme, to retrospectively assess the impact of altering the FIT positivity threshold, adjusting it to correspond with neighbouring European countries, on CRC detection rates through screening in Ireland between 2013 and 2021. All analyses were conducted on Stata 17. Results 1,552 individuals were diagnosed with CRC in Ireland after a positive FIT performed through BowelScreen between 2013-2021. Adopting the same FIT positivity thresholds as the Netherlands (47µg/g), Scotland (80µg/g), England (120µg/g) and Wales (150µg/g) would have resulted in 21 (1.4%), 262 (17.1%), 458 (29.8%) and 556 (36.2%) fewer diagnoses of CRC through BowelScreen during this period, respectively. Additionally, increasing the positivity threshold to correspond with these countries would have resulted in between 1.7-41.9% fewer stage 1, between 1.0-30.9% fewer stage 2, between 1.4-32.9% fewer stage 3 and between 0-5.6% fewer stage 4 CRCs detected. Conclusions Changing the FIT positivity threshold in Ireland to correspond with that of other neighbouring European countries would have reduced the detection of CRC through screening to varying degrees. The detection of stage 1 CRCs would have been most greatly reduced, but up to almost a third of all stage 2 and stage 3 CRCs would not have been detected if some alternative, higher positivity thresholds were adopted. Key messages • Increasing the FIT positivity threshold in Ireland will need careful consideration to keep the optimum positive predictive value of a colonoscopy. • Lower stage 1-3 CRC detection rates may occur as a result.

Interval cancers in a national colorectal screening programme based on faecal immunochemical testing: Implications for faecal haemoglobin concentration threshold and sex inequality.

To compare interval cancer proportions (ICP) in the faecal immunochemical test (FIT)-based Scottish Bowel Screening Programme (SBoSP) with the former guaiac faecal occult blood test (gFOBT)-based SBoSP and investigate associations between interval cancer (IC) and faecal haemoglobin concentration (f-Hb) threshold, sex, age, deprivation, site, and stage. The ICP data from first year of the FIT-based SBoSP and the penultimate year of the gFOBT-based SBoSP were compared in a prospective cohort design. With FIT, 801 colorectal cancers (CRCs) were screen detected (SDC), 802 were in non-participants, 548 were ICs, 39 were colonoscopy missed and 72 were diagnosed after incomplete screening; with gFOBT: 540, 904, 556, 45, and 13, respectively. FIT had a significantly higher proportion of SDC compared to IC than gFOBT. For FIT and gFOBT, ICP was significantly higher in women than men. As f-Hb threshold increased, ICP increased and, for any f-Hb threshold for men, a lower threshold was required for comparable ICP in women. In Scotland, the current threshold of ≥80 µg Hb/g faeces would have to be lowered to ≥40 µg Hb/g faeces for women to achieve sex equality for ICP. In the FIT-based SBoSP, there were four times as many stage I SDC than IC. This was reversed in advanced stages, with twice as many stage IV CRC diagnosed as IC versus SDC. Reducing the numbers of IC requires lowering the f-Hb threshold. Using different f-Hb thresholds for women and men could eliminate the sex disparity, but with additional colonoscopy.

Improved stage and survival for patients in the Aotearoa New Zealand colorectal cancer screening program 2012-2019.

Colorectal cancer (CRC) screening was introduced in Aotearoa New Zealand at Waitematā District Health Board (WDHB) in late 2011. This study reviewed patterns of disease, treatment received, and survival of patients with national bowel screening program (NBSP)-detected CRC versus non-NBSP patients at WDHB 2012-2019. Data collected retrospectively for all patients with adenocarcinoma of the colon or rectum at WDHB 2012-2019. Patient records were manually reviewed. Chi-square, Fisher's exact test and the Mann Whitney U-test used as appropriate. Kaplan-Meier and Cox proportional hazards regression modelling for survival analysis. 1667 patients included (360 NBSP and 1307 non-NBSP). 863 (51.8%) were male. Median age at diagnosis 73 years (range 21-100); NBSP patients were younger (median 68 vs. 76 years, P < 0.001). NBSP patients had significantly lower T, N, M and overall TNM stage than non-BSP patients. Median survival estimate on Kaplan-Meier analysis was 94 months for all patients. Statistically significant (P < 0.05) predictors of mortality on multi-variate regression analysis included increasing overall TNM stage compared with stage I (stage II HR 1.63 (95% CI 1.14-2.34), stage III HR 2.86 (95% CI 2.03-4.03), stage IV HR 7.73 (95% CI 5.59-10.68)), diagnosis within NBSP (HR 0.51 (95% CI 0.37-0.71)), increasing age in years (HR 1.03 (95% CI 1.02-1.03)), urgent/emergency surgery (HR 1.66 (95% CI 1.36-2.01)) and formal resection of primary tumour (HR 0.31 (95% CI 0.25-0.38)). Patients diagnosed within the Aotearoa New Zealand NBSP were found to be younger and have earlier stage CRC. Diagnosis within the NBSP is an independent predictor of survival for patients with CRC.

Improved use of faecal immunochemical tests for haemoglobin in the Scottish bowel screening programme.

This study aimed to develop a risk-scoring model in the Scottish Bowel Screening Programme incorporating faecal haemoglobin concentration with other risk factors for colorectal cancer. Data were collected for all individuals invited to participate in the Scottish Bowel Screening Programme between November 2017 and March 2018 including faecal haemoglobin concentration, age, sex, National Health Service Board, socioeconomic status, and screening history. Linkage with The Scottish Cancer Registry identified all screening participants diagnosed with colorectal cancer. Logistic regression was performed to identify which factors demonstrated significant association with colorectal cancer and could be used in the development of a risk-scoring model. Of 232,076 screening participants, 427 had colorectal cancer: 286 diagnosed following a screening colonoscopy and 141 arising after a negative screening test result giving an interval cancer proportion of 33.0%. Only faecal haemoglobin concentration and age showed a statistically significant association with colorectal cancer. Interval cancer proportion increased with age and was higher in women (38.1%) than men (27.5%). If positivity in women were mirrored in men at each age quintile interval cancer proportion would still have remained higher in women (33.2%). Moreover, an additional 1201 colonoscopies would be required to detect 11 colorectal cancers. Development of a risk scoring model using early data from the Scottish Bowel Screening Programme was not feasible due to most variables showing insignificant association with colorectal cancer. Tailoring the faecal haemoglobin concentration threshold according to age could help to diminish some of the disparity in interval cancer proportion between women and men. Strategies to achieve sex equality using faecal haemoglobin concentration thresholds depend considerably on which variable is selected for equivalency and this requires further exploration.

Increasing uptake of FIT colorectal screening: protocol for the TEMPO randomised controlled trial testing a suggested deadline and a planning tool

IntroductionScreening can reduce deaths from colorectal cancer (CRC). Despite high levels of public enthusiasm, participation rates in population CRC screening programmes internationally remain persistently below target levels. Simple behavioural interventions...

What are common barriers and helpful solutions to colorectal cancer screening? A cross-sectional survey to develop intervention content for a planning support tool

ObjectiveColorectal screening using faecal immunochemical tests (FITs) can save lives if the people invited participate. In Scotland, most people intend to complete a FIT but this is not reflected in...

Do faecal test-based colorectal cancer screening pilots provide data that are reflected in subsequent programmes? Evidence from interval cancer proportions.

Guidelines on colorectal cancer (CRC) screening with guaiac faecal occult blood tests (gFOBTs) and faecal immunochemical tests (FITs) include the need for a pilot before a programme is introduced. Interval cancers (ICs), cancers arising after a negative screening test result but before the next scheduled invite, are important indicators of programme quality. Our aim was to compare IC in the gFOBT-based Scottish Bowel Screening Programme (SBoSP), a FIT-based pilot, and the FIT-based SBoSP, to assess if the pilot provided data that was reflected in the subsequent programme. The IC proportions (ICPs) data ([IC/(IC + screen detected CRC)] x 100) from the penultimate year of the gFOBT-based SBoSP, the 6-month pilot and the first year of the FIT-based SBoSP were compared. To ensure appropriate comparison, these data were only from the two pilot NHS Boards. For all participants, and females and males, the ICPs were very similar in the gFOBT-based SBoSP and the pilot. The faecal haemoglobin concentration (f-Hb) threshold for the pilot was set at ≥80μg Hb/g faeces. However, in marked contrast, in the FIT-based SBoSP, at the same threshold, the ICPs were lower. In all three groups, the ICPs were higher in females than in males. Data on variables in pilots, including ICP, can be informative, but only if variables such as FIT system are held consistent between pilot and programme. Lowering the f-Hb threshold for females to give the same ICP as males might be a strategy to minimise sex inequality.

Route to diagnosis of colorectal cancer and association with survival within the context of a bowel screening programme

ObjectivesBowel cancer screening has been introduced to improve colorectal cancer outcomes; however, a significant proportion of cases continue to present with TNM Stage III-IV disease and/or emergently. This study analyses the prior interaction with screening of patients diagnosed with colorectal cancer and factors associated with non-screening diagnosis. Study designThis was a retrospective observational study. MethodsAll patients diagnosed with colorectal cancer in the West of Scotland from 2011 to 2014 were identified. Through data linkage to the Scottish Bowel Cancer Screening Programme, we analysed patient interaction with screening within 2 years before cancer diagnosis. ResultsIn total, 6549 patients were diagnosed with colorectal cancer, 1217 (19%) via screening. Screening participation was associated with earlier TNM stage, reduced emergency presentations and improved 3-year survival (all P < 0.001). Failure to diagnose through screening was predominantly due to non-invitation (37%), non-return of screening test (29%) or negative test (13%). Three hundred fifty-one patients were below screening age, 79% of whom were aged 40–49 years and 2035 patients were above screening age. Factors associated with non-return of screening test included age, sex, SIMD (all P < 0.001) and raised Charlson score (P = 0.030). Factors associated with negative screening result included sex, anaemia, differentiation, right-sided tumours and venous invasion (P < 0.001). ConclusionWithin Scotland, <20% of colorectal cancer is diagnosed through screening despite the existence of a population screening programme. Measures must be taken to improve screening participation including encouragement of those of routine screening age and those age ≥75 years in good health to participate in screening with consideration given to extending screening to under 50s. A significant false-negative rate of testing was observed in the present study and this requires further investigation within a population undergoing screening through faecal immunochemical testing.

Relationship between BMI, CT-derived body composition and colorectal neoplasia in a bowel screening population.

IntroductionObesity is associated with an increased risk of colorectal cancer (CRC). Unlike the indirect measures such as BMI, CT-Body composition (CT-BC) allows for the assessment of both volume and distribution of adipose tissue. Therefore, the aim of this study was to examine the relationship between host characteristics, BMI, CT-BC measurements and the incidence of colorectal neoplasia.MethodsPatients undergoing CT Colonography (CTC) as part of the Scottish Bowel Screening Programme, between July 2009 and February 2016, were eligible for inclusion. Data were collected including demographic data, clinicopathological variables and CT-BC measurements including skeletal muscle index (SMI), subcutaneous fat index (SFI) and visceral fat area (VFA). CTC, colonoscopy, and pathology reports were used to identify CRC incidence. Associations between demographic data, clinicopathological variables, CT-BC measurements, colorectal neoplasia and advanced colorectal neoplasia were analysed using univariate and multivariate binary logistics regression.Results286 patients met the inclusion criteria. Neoplasia was detected in 105 (37%) of the patients with advanced neoplasia being detected in 72 (69%) of patients. On multivariate analysis sex (p < 0.05) and high VFA (p < 0.001) remained independently associated with colorectal neoplasia. On multivariate analysis a high SFI (p < 0.01) remained independently associated with advanced colorectal neoplasia. BMI was not associated with either colorectal neoplasia or advanced colorectal neoplasia.ConclusionWhen directly compared to BMI, CT derived fat measurements were more closely associated with the degree of neoplasia in patients undergoing colorectal cancer screening. In patients investigated with CT colonography, CT adipose measures may stratify the risk and grade of neoplasia.

Why are most colorectal cancers diagnosed outside of screening? A retrospective analysis of data from the English bowel screening programme.

ObjectiveDespite several interventions to increase participation in England, most colorectal cancers (CRCs) are diagnosed outside of the screening programme. The aims of this study were to better understand why most CRCs are diagnosed externally, the extent to which this is due to suboptimal uptake of screening, and the extent to which it is due to other factors, such as false-negative test results.Setting / MethodsWe performed a clinical audit of 1011 patients diagnosed with CRC at St Mark's Hospital (Harrow, UK) between January 2017 and December 2020. Data on the diagnostic pathway and screening history of individuals were extracted from the bowel cancer screening system and assessed using descriptive statistics.Results446/1011 (44.1%) patients diagnosed with CRC were eligible for screening at the time of diagnosis. Of these, only 115/446 (25.8%) were diagnosed through screening. Among those diagnosed via non-screening pathways, 210/331 (63.4%) had never taken part in screening, 31/331 (9.4%) had taken part but were not up to date, and 89/331 (26.9%) had taken part and were up-to-date (of these, 82/89 [92.2%] had received a normal or weak positive test result, and 5/89 [5.6%] had received a positive result and declined colonoscopy).ConclusionNearly two-thirds of screening eligible patients diagnosed through a non-screening pathway had never taken part in screening. This represents the single largest source of inefficiency within the screening programme, followed by missed findings and inconsistent participation. Given the improved outcomes associated with screen-detected cancers, there is a strong public health mandate to encourage participation.

Using fecal immunochemical test values below conventional cut-off to individualize colorectal cancer screening.

Background and study aims Of the participants in the Danish screening program, 89.9 % to 92.5 % have fecal immunochemical test (FIT) values < 10 μg/g feces (equivalent to 50 ng hemoglobin/mL buffer). This study aimed to investigate the risk of interval colorectal cancer (CRC) in this group before the next biennial screening round. Patients and methods This cohort study included all citizens from the region of Southern Denmark who participated in the Danish bowel screening program from 2014 trough 2016 and had a FIT value < 10 μg/g feces. Individuals receiving a CRC diagnosis were identified through the national CRC registry, with a follow up of 2 years corresponding to the current screening interval. We also examined the 3-year CRC incidence. Hazard ratios (HRs) were estimated using univariate and multivariate Cox proportional hazard regression models. Results Data from 185,654 citizens presenting with a FIT value < 10 μg/g feces were eligible for analysis. Overall, interval CRC incidence was 0.07 % within 2 years with HRs of 4.16 (95 % confidence interval [CI] 2.67;6.48) and 5.8 (95 % CI 3.34;10.05) for FIT values of 4 to 6.9 μg/g feces and 7 to 9.9 μg/g feces, respectively, compared to those having a FIT value below the limit of quantification of 4 μg/g feces. After 3 years, the overall CRC incidence increased to 0.14 %; however, this was not significant. Conclusions This study demonstrates a positive correlation between FIT value and risk of interval cancer even for very low values. It further suggests that an increase in the screening interval could be reasonable in the low FIT categories.

Adenoma and serrated lesion detection with distal attachment in screening colonoscopy: a randomized controlled trial.

Adenoma detection rate (ADR) is the single most important measure of quality in colonoscopy, but little is known about the detection rate of serrated lesions (SLDR). To improve ADR, Endocuff Vision (EV) can be used. Studies have shown differing results as to the effect on ADR; an effect on SLDR has not been shown. To investigate the effect of Endocuff Vision on ADR in a screening population, this randomized controlled open label trial with concealed allocation was performed. Randomization to trial group was carried out by the endoscopist using prepared numbered envelopes. Patients referred as part of the national bowel screening program at Regional Hospital Herning, Denmark were recruited and allocated to one of two groups: Endocuff Vision colonoscopy (EVC) and standard colonoscopy (SC). Outcomes were ADR, mean number, site, and size of lesions per procedure. SLDR as outcome was added after inclusion had begun. A total of 1178 participants were included, with 1166 (EVC 583 and SC 583) available for analysis. There was no clinical relevant difference in ADR (59.2% [CI 55.1; 63.1] v 60.5% [CI 56.5; 64.4]) or SLDR (13.0% [CI 10.5; 16.0] v 10.3% [CI 8.0; 13.0]) between groups. More serrated lesions were found per procedure (MSP) (0.2 v 0.1, IRR 57% [CI 17; 109]. Removal rate of EV was similar in the two study groups. We found no significant effects of the use of Endocuff Vision on ADR, when compared to standard colonoscopy, but more serrated lesions were detected in the Endocuff group. Clinical Trials NCT04651062.

Diagnostic variability in the histopathological assessment of advanced colorectal adenomas and early colorectal cancer in a screening population.

AimThe aim of this study was to evaluate interobserver variability between individual pathologists and a panel of pathologists in the histopathological assessment of advanced colorectal neoplasms in the Dutch bowel cancer screening population.Methods and resultsHistological slides of adenomas with high‐grade dysplasia and early colorectal carcinomas (CRC) from 20 different laboratories were reviewed by the pathology panel of the Dutch bowel screening programme. Interobserver variability was reported by descriptive statistics. In addition, potential clinical consequences of discrepancies were evaluated. A total of 104 cases of adenomas with high‐grade dysplasia and 83 early CRCs were reviewed. Discrepancies were observed in 41 of 104 (39.4%) adenoma cases, which potentially had clinical consequences in 16 (15.4%) cases. For CRC, discrepancies were shown in 44 of 83 cases (53.0%) and would have potentially led to alternative treatment strategies in 25 (30.1%) cases. Most frequently, discrepancies were observed in the assessment of lymphovascular invasion (23 of 73 cases, 31.5%).ConclusionThis study showed that considerable interobserver variability is present in the histopathological assessment of advanced colorectal neoplasia, which may impact upon treatment choices. Additional stains and education, as well as intercollegial consultation, might decrease this variability.

An overview of colorectal cancer in the Australian healthcare system over the past 20 years

Colorectal cancer (CRC) places a heavy burden on both the Australian health care system and the economy. CRC is the third most diagnosed cancer and carries the second highest cause of mortality. Prognosis has improved over recent years attributable to multiple factors including the introduction of a free national bowel screening program, improvements in medical and surgical treatment, and nationally funded subsidisation of some treatments. However, given Australia’s ageing population and that the incidence of CRC increases with age, this disease is likely to continue to place a heavy burden on the health economy. This paper provides an overview of the management of CRC in the context of the Australian health system over the past 20 years. It will consider the epidemiology of CRC, the various cancer registries that exist in Australia, the structure of the Australian healthcare system (mixed public and private) in which patients are treated, and finally the treatment options available to patients with either primary or metastatic CRC.

Faecal haemoglobin concentrations in women and men diagnosed with colorectal cancer in a national screening programme

ObjectiveThere is evidence that colorectal cancer screening using faecal haemoglobin is less effective in women than men. The faecal haemoglobin concentrations were therefore examined in women and men with screen-detected colorectal cancer.SettingScottish Bowel Screening Programme, following the introduction of a faecal immunochemical test from November 2017, to March 2020.MethodsData were collated on faecal haemoglobin concentrations, pathological stage and anatomical site of the main lesion in participants who had colorectal cancer detected. The data in women and men were compared.ResultsFor the faecal haemoglobin concentrations studied (>80 µg Hb/g faeces), the distributions indicated lower concentrations in women. Marked differences were found between women and men diagnosed with colorectal cancer. The median faecal haemoglobin concentration for women (n = 720) was 408 µg Hb/g faeces compared to 473 µg Hb/g faeces for men (n = 959) (p = 0.004) and 50.6% of the results were >400 µg Hb/g faeces in women; in men, this was 57.8%. The difference in faecal haemoglobin concentrations in women and men became less statistically significant as stage advanced from stages I–IV. For right-sided, left-sided and rectal colorectal cancer, a similar gender difference persisted in all sites. Differences in faecal haemoglobin between the genders were significant for left-sided cancers and stage I and approached significance for rectal cancers and stage II, but all sites and stages showed lower median faecal haemoglobin concentrations for women.ConclusionsTo minimise gender inequalities, faecal immunochemical test-based colorectal cancer screening programmes should evaluate a strategy of using different faecal haemoglobin concentration thresholds in women and men.

TP1.2.4The incidence, implications and risk factors for extracolonic findings at CT colonography in a bowel screening population

Abstract Aim CT virtual colonoscopy (CTC) is increasingly relied upon in bowel screening programmes. Concern remains regarding the prevalence of incidental extra-colonic findings (ECF). The present study reports on the prevalence and implications of ECF as part of a UK bowel screening programme. Methods Reports for 400 consecutive CTCs carried out as part of the Scottish Bowel Screening Programme were examined. Intra and extracolonic findings were recorded using the CT Colonography Reporting and Data System (C-RADS). Medical records pertaining to ECF follow-up were examined. Cost analysis was performed. Results 394 patients were included. 146 (37%) were males. Median age was 65 years, median follow-up was 72 months (Range 32-110). 92 (23%) patients had CTC as their primary investigation, 302 (77%) patients underwent CTC due to failed colonoscopy. Overall, 244/394 (62%) patients had ECF with only 45/394 (11%) found to have colonic pathology. 65/394 (16%) had moderately or highly significant ECF, (C-RADS E3-4). Of the 244 patients with ECF, 59 (24%) underwent further investigation, estimated cost £17,589. The majority, 37/59 (63%) were found to have benign disease after follow-up. Conclusion ECF at CTC are more frequent than colonic findings. The majority of ECF investigated are found to be benign yet a quarter of ECF are further investigated at a cost to the health service and the patient. Clinicians should be judicial when ordering and consenting patients with regards ECF and its implications if CTC is considered. Particularly when the test is part of a public funded and voluntary screening programme.

SP1.1.17The relationship between colorectal neoplasia and body composition in a bowel screening population

Abstract Aims Conflicting evidence exists as to the effect of elevated BMI in the development of colorectal neoplasia. Yet BMI is a crude measure of adiposity. The present study investigates the association between CT derived measures of body composition including sarcopenia, subcutaneous fat index (SFI) and visceral obesity and colorectal neoplasia. Methods 358 consecutive patients undergoing CT virtual colonoscopy (CTC) as part of the Scottish Bowel Screening Programme were eligible for inclusion. Demographic data and the above measures body composition were calculated using previously published CT derived methods. Medical records were examined for colonoscopic findings and pathology reports. Results 121/358 (34%) were males. Median age 65. 126/358 (35%) patients were found to have a colorectal neoplasia. 84/126 (67%) had advanced neoplasia. 26/358 (7%) had adenocarcinoma. On multivariable analysis, both male sex and visceral obesity was associated with the presence of colorectal neoplasia, OR 2.62, [95% CI 1.51-4.55, p = 0.001] and OR 2.83, {95% CI 1.25-6.41, p = 0.01] respectively. The relationship was dose dependent with an increased risk of colorectal neoplasia in the 3rd [OR 2.13 95% CI 1.09-4.14 p &amp;lt; 0.05] and 4th [OR 3.77 95% CI 1.96-7.26 p &amp;lt; 0.001] quartiles of visceral fat area. BMI, SFI and sarcopenia were not associated with colorectal neoplasia in the present study. Conclusions Male sex and in particular, visceral obesity is associated with increased risk of colorectal neoplasia. In addition to the known cardiovascular and metabolic dangers of visceral obesity, the present work suggests that visceral obesity may also play a role in colorectal neoplasia formation.

EP.WE.279Impact of COVID-19 on West of Scotland Colorectal Cancer Services

Abstract Aim The coronavirus disease-19 (COVID-19) pandemic has driven unprecedented restriction of the National Health Service to accommodate additional pressures. Our aim was to analyse the impact of COVID-19 on the largest colorectal cancer (CRC) services in NHS Greater Glasgow &amp; Clyde. Method Audit data collected from multidisciplinary team meetings for South Glasgow CRC service were accessed. We compared April-June 2020 (‘Lockdown group’) to corresponding months in 2019 (‘Control group’). Statistical analysis by unpaired T-test, Pearson’s χ2 test with post hoc analysis using adjusted Z scores and Bonferroni correction. Results There was a 39.5% reduction in CRC diagnoses during lockdown (n = 49) compared to control (n = 81). There was a 34.1% reduction in CRC operations during lockdown (n = 27) compared to control (n = 52). The proportion of patients managed operatively did not differ between groups (p = 0.140). There was no difference in the number of days from diagnosis to first treatment between Lockdown and Control groups (Mean(SD): 40.1±35.3 and 43.2±42.9, p = 0.257). Primary care physicians were the main referral source for both lockdown (52%) and control groups (46%). The cessation of bowel screening programme saw no referrals in lockdown whereas it accounted for 21% of referrals in control group, p &amp;lt; 0.001). Conclusions We experienced dramatic reductions in CRC diagnoses during lockdown that was not only accounted for by the cessation of bowel screening. The diagnostic delay in the 39.5% ‘missed’ CRC patients may result in patient morbidity; a severe repercussion of COVID-19. The resurgence of COVID-19 cases poses a real threat to cancer services.