Do risk scores improve use of faecal immunochemical testing for haemoglobin in symptomatic patients in primary care?

AIM: Faecal immunochemical testing (FIT) is used in the detection of colorectal cancer (CRC). FIT is invariably used at a single faecal haemoglobin (f-Hb) concentration threshold. The aim of this observational study was to explore risk scoring models (RSMs) with f-Hb and other risk factors for CRC in symptomatic patients attending primary care, potentially speeding diagnosis and saving endoscopy resources. METHOD: Records of patients completing FIT were linked with The Scottish Cancer Registry and with other databases with symptoms, full blood count and demographic variables, and randomized into derivation and validation cohorts. Stepwise multivariable logistic regression created RSMs assessed in the validation cohort. RESULTS: Of 18 805 unique patients, 9374 and 9431 were in the derivation and validation cohorts, respectively: f-Hb, male sex, increasing age, iron deficiency anaemia and raised systemic immune inflammation index created the final RSM. A risk score threshold of ≥2.363, generating the same number of colonoscopies as a f-Hb threshold of ≥10 µg Hb/g gave improved sensitivity for CRC in both cohorts. A RSM which excluded f-Hb was used to investigate the effect of raising the f-Hb threshold from ≥10 to ≥20 µg Hb/g in those with a low risk score. This approach would have generated 234 fewer colonoscopies but missed four CRCs. CONCLUSION: The RSM conferred no significant benefit to patients with very low f-Hb and CRC. Alternative strategies combining FIT with other variables may be more appropriate for safety-netting of symptomatic patients. Further work to develop and investigate the value of RSM for significant bowel disease other than CRC may also be beneficial.

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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Impact of faecal haemoglobin based triage of bowel symptoms presenting to primary care on colorectal cancer diagnosis.

AIM: Faecal immunochemical testing (FIT) for faecal haemoglobin was introduced into primary care in National Health Service Tayside in 2015 as an adjunct to clinical assessment of new bowel symptoms. We aimed to assess the impact of FIT-based triage in primary care on colorectal cancer (CRC) diagnosis. METHOD: Cancer audit data between January 2016 and December 2019 were reviewed to identify all patients diagnosed locally with CRC. The mode of presentation and stage at diagnosis were noted and patient records were interrogated to identify whether FIT and full blood count (FBC) had been performed prior to referral. Results were compared between the FIT and non-FIT groups. RESULTS: In all, 1245 patients were diagnosed with CRC of whom 581 (46.7%) presented through primary care. FIT was performed prior to referral in 440/581 (75.7%), with the proportion increasing from 62.3% in 2016 to 85.8% in 2019. At faecal haemoglobin ≥10 µg Hb/g faeces, sensitivity for CRC was 94.1%. Over the study period the annual proportion of non-emergency presentations increased significantly; presentations from primary care increased from 43.1% to 53.5% (P = 0.0096). After excluding non-FIT patients who had an overt CRC at referral, there was no difference in stage at diagnosis between FIT and non-FIT cancers. Safety-netting with FBC was widely used in our cohort with 97.3% of FIT patients having also had FBC. CONCLUSION: FIT-based triage of new bowel symptoms in primary care is associated with increased non-emergency presentation of CRC but this did not influence stage at diagnosis.

Prevalence of repeat faecal immunochemical testing in symptomatic patients attending primary care.

AIM: The faecal immunochemical test (FIT) for faecal haemoglobin (f-Hb) helps determine the risk of colorectal cancer (CRC) and has been integrated into symptomatic referral pathways. 'Safety netting' advice includes considering referral for persistent symptoms, but no published data exists on repeated FITs. We aimed to examine the prevalence of serial FITs in primary care and CRC risk in these patients. METHOD: A multicentre, retrospective, observational study was conducted of patients with two or more consecutive f-Hb results within a year from three Scottish Health Boards which utilize FIT in primary care. Cancer registry data ensured identification of CRC cases. RESULTS: Overall, 135 396 FIT results were reviewed, of which 12 359 were serial results reported within 12 months (9.1%), derived from 5761 patients. Of these, 42 (0.7%) were diagnosed with CRC. A total of 3487 (60.5%) patients had two f-Hb < 10 µg/g, 944 (16.4%) had f-Hb ≥ 10 µg/g followed by <10 µg/g, 704 (12.2%) f-Hb < 10 µg/g followed by ≥10 µg/g and 626 (10.9%) had two f-Hb ≥ 10 µg/g. The CRC rate in each group was 0.1%, 0.4%, 1.4% and 4.0%, respectively. Seven hundred and thirty four patients submitted more than two FITs within a year. The likelihood of one or more f-Hb ≥ 10 µg/g rose from 40.4% with two samples to 100% with six, while the CRC rate fell from 0.8% to 0%. CONCLUSION: Serial FITs within a year account for 9.1% of all results in our Boards. CRC prevalence amongst symptomatic patients with serial FIT is lower than in single-FIT cohorts. Performing two FITs within a year for patients with persistent symptoms effectively acts as a safety net, while performing more than two within this timeframe is unlikely to be beneficial.

Faecal haemoglobin concentration in adenoma, before and after polypectomy, approaches the ideal tumour marker.

BACKGROUND: Polypectomy may be performed at colonoscopy and then subsequent surveillance undertaken. It is thought that faecal haemoglobin concentration (f-Hb), estimated by quantitative faecal immunochemical tests (FIT), might be a useful tumour marker. METHODS: Consecutive patients enrolled in colonoscopy surveillance were approached at two hospitals. A specimen for FIT was provided before colonoscopy and, ideally after 3 weeks, a second FIT sample from those who had polypectomy. A single FIT system (OC-Sensor io, Eiken Chemical Co., Ltd) was used to generate f-Hb. RESULTS: 1103 Patients were invited; 643 returned a FIT device (uptake: 58.3%). Four patients had known inflammatory bowel disease (IBD) and were excluded, leaving 639 (57.9%) with an age range of 25-90 years (median 64 years), 54.6% male. Of 593 patients who had a f-Hb result and completed colonoscopy, advanced neoplasia was found in 41 (6.9%); four colorectal cancer (CRC): 0.7% and 37 advanced adenoma (AA): 6.3%, and a further 127 (21.4%) had non-advanced adenoma (NAA). The median f-Hb was significantly greater in AA as compared to NAA; 6.0 versus 1.0 µg Hb/g faeces, p < 0.0001.134/164 (81.7%) of invited patients returned a second FIT device: 28 were patients with AA in whom median pre-polypectomy f-Hb was 19.2, falling to 3.5 µg Hb/g faeces post-polypectomy, p = 0.01, and 106 with NAA had median pre-polypectomy f-Hb 0.8 compared to 1.0 µg Hb/g faeces post-polypectomy, p = 0.96. CONCLUSIONS: Quantitative FIT could provide a good tumour marker in post-polypectomy surveillance, reduce colonoscopy requirements and minimise potential risk to patients.

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

OBJECTIVE: There 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. SETTING: Scottish Bowel Screening Programme, following the introduction of a faecal immunochemical test from November 2017, to March 2020. METHODS: Data 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. RESULTS: For 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. CONCLUSIONS: To 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.

Yield of colorectal cancer at colonoscopy according to faecal haemoglobin concentration in symptomatic patients referred from primary care.

AIM: Lower gastrointestinal (GI) symptoms are poor predictors of colorectal cancer (CRC). The aim of this study was to examine the diagnostic yield of colonoscopy by faecal haemoglobin (f-Hb) concentration in symptomatic patients assessed in primary care by faecal immunochemical testing (FIT). METHOD: In three Scottish NHS Boards, FIT kits (HM-JACKarc, Hitachi Chemical Diagnostics Systems Co., Ltd, Tokyo, Japan) were used by general practitioners to guide referrals for patients with lower GI symptoms (laboratory data studied for 12 months from December 2015 onwards in Tayside, 18 months from June 2018 onwards in Fife and 5 months from September 2018 onwards in Greater Glasgow and Clyde). Cases of CRC diagnosed at colonoscopy were ascertained from colonoscopy and pathology records. RESULTS: Four thousand eight hundred and forty one symptomatic patients who underwent colonoscopy after FIT submission were included. Of the 2166 patients (44.7%) with f-Hb <10 µg Hb/g faeces (µg/g), 14 (0.6%) were diagnosed with CRC, with a number needed to scope (NNS) of 155. Of the 2675 patients (55.3%) with f-Hb ≥10 µg/g, 252 were diagnosed with CRC (9.4%) with a NNS of 11. Of the 705 patients with f-Hb ≥400 µg/g, 158 (22.4%) were diagnosed with CRC with a NNS of 5. Over half of those diagnosed with CRC with f-Hb <10 µg/g had coexisting anaemia. CONCLUSION: Symptomatic patients with f-Hb ≥10 µg/g should undergo further investigation for CRC, while higher f-Hb concentrations could be used to triage for urgency during the COVID-19 recovery phase. Patients with f-Hb <10 µg/g and without anaemia are very unlikely to be diagnosed with CRC and the majority need no further investigation.

Faecal haemoglobin concentration thresholds for reassurance and urgent investigation for colorectal cancer based on a faecal immunochemical test in symptomatic patients in primary care.

BACKGROUND: Faecal haemoglobin concentration (f-Hb), estimated using a faecal immunochemical test, can be safely implemented in primary care to assess risk of colorectal cancer (CRC). Clinical outcomes of patients presenting with symptoms of lower gastrointestinal disease were examined using an extensive range of f-Hb thresholds to decide on reassurance or referral for further investigation. METHODS: All patients who attended primary care and submitted a single faecal specimen faecal immunochemical test in the first year of the routine service had f-Hb estimated using HM-JACKarc: f-Hb thresholds from <2 to ≥ 400 µg Hb/g faeces (µg/g) were examined. RESULTS: Low f-Hb thresholds of <2, <7, <10 and <20 µg/g gave respective CRC risks of 0.1, 0.3, 0.3 and 0.4%, numbers needed to scope for one CRC of 871, 335, 300 and 249, and 'false negative' rates of 2.9, 11.4, 13.3 and 17.1%. With thresholds of <2, <7, <10 and <20 µg/g, 48.6, 74.6, 78.1 and 83.2% respectively of symptomatic patients could be managed without further investigation. With reassurance thresholds of <2 µg/g, <7 µg/g and <10 µg/g, the thresholds for referral for urgent investigation would be >400 µg/g, ≥200 µg/g and ≥100 µg/g. However, patients with a f-Hb concentration of <10 or <20 µg/g with iron deficiency anaemia, or with severe or persistent symptoms, should not be denied further investigation. CONCLUSIONS: In primary care, f-Hb, in conjunction with clinical assessment, can safely and objectively determine individual risk of CRC and decide on simple reassurance or urgent, or routine referral.

The impact of hypothetical PErsonalised Risk Information on informed choice and intention to undergo Colorectal Cancer screening colonoscopy in Scotland (PERICCS)-a randomised controlled trial.

BACKGROUND: There is currently no existing evidence on the effects of personalised risk information on uptake of colonoscopy following first line screening for colorectal cancer. This study aimed to measure the impact of providing risk information based on faecal haemoglobin concentration to allow a fully informed choice around whether or not to undergo colonoscopy. METHODS: Two thousand seven hundred sixty-seven participants from the Scottish Bowel Screening Programme (SBoSP) database, who had not recently been invited for screening, were randomised to receive one of three types of hypothetical risk information materials: (1) numerical risk information (risk categories of one in 40, one in 1600 and one in 3500), (2) categorical risk information (highest, moderate and lowest risk), or (3) positive screening result letter (control group). The primary outcome was the impact of the risk materials on intention to undergo colonoscopy, to allow comparison with the current colonoscopy uptake of 77% for those with a positive screening result in the SBoSP. Secondary outcomes were knowledge, attitudes and emotional responses to the materials. RESULTS: Four hundred thirty-four (15.7%) agreed to participate with 100 from the numerical risk group (69.0%), 104 from the categorical risk group (72.2%) and 104 from the control group (71.7%) returning completed materials. Intention to undergo colonoscopy was highest in the highest risk groups for the numerical and categorical study arms (96.8% and 95.3%, respectively), but even in the lowest risk groups was > 50% (58.1% and 60.7%, respectively). Adequate knowledge of colorectal screening and the risks and benefits of colonoscopy was found in ≥ 98% of participants in all three arms. All participants reported that they found the information easy-to-understand. 19.1%, 24.0% and 29.6% of those in the numerical, categorical and control group, respectively, reported that they found the information distressing (p > 0.05). CONCLUSIONS: Applying the risk categories to existing SBoSP data shows that if all participants were offered an informed choice to have colonoscopy, over two thirds of participants would intend to have the test. Equating to an increase in the number of screening colonoscopies from approx. 14,000 to 400,000 per annum, this would place an unmanageable demand on colonoscopy services, with a very small proportion of cancers and pre-cancers detected. However, the response to the materials were very positive, suggesting that providing risk information to those in lowest and moderate risk groups along with advice that colonoscopy is not currently recommended may be an option. Future research would be required to examine actual uptake. TRIAL REGISTRATION: Date applied 1 December 2017 ISRCTN number 14254582 .

Measurement of faecal haemoglobin with a faecal immunochemical test can assist in defining which patients attending primary care with rectal bleeding require urgent referral.

BACKGROUND: Current guidelines document persistent rectal bleeding as an alarm symptom in patients presenting to primary care. We studied whether a faecal immunochemical test could assist in their assessment. METHODS: From December 2015, faecal immunochemical tests were routinely available to primary care when assessing patients with new-onset bowel symptoms: general practitioners were encouraged to include faecal haemoglobin concentration (f-Hb) within any referral to secondary care. Results with f-Hb ≥10 µg Hb/g faeces were defined as positive. The incidence of significant bowel disease (SBD: colorectal cancer [CRC], higher-risk adenoma [HRA: any ≥1 cm, or three or more] and inflammatory bowel disease [IBD]) at subsequent colonoscopy, referred symptoms and f-Hb were recorded. RESULTS: Of 1447 patients with a faecal immunochemical test result and colonoscopy outcome, SBD was diagnosed in 296 patients (20.5%; 95 with CRC, 133 with HRA, and 68 with IBD). Four hundred and sixty-two patients (31.9%) reported rectal bleeding: 294 had f-Hb ≥10 µg Hb/g faeces. At colonoscopy, 105/294 had SBD versus 14/168 with rectal bleeding and f-Hb <10 µg Hb/g faeces (P < 0.0001), comprising one case of CRC (0.6%), 12 HRA (7.1%) and one new case of IBD (0.6%); further, the single cancer and 8 of the 12 HRA were located in the descending colon. CONCLUSION: Patients with rectal bleeding and f-Hb <10 µg Hb/g faeces are unlikely to have SBD and could be investigated by sigmoidoscopy alone. Using the faecal immunochemical test to guide investigation of patients with rectal bleeding is a rational and practical way forward.

Faecal haemoglobin distributions by sex, age, deprivation and geographical region: consequences for colorectal cancer screening strategies.

Objectives Faecal immunochemical tests for haemoglobin (FIT) are becoming widely used in colorectal cancer (CRC) screening and assessment of symptomatic patients. Faecal haemoglobin concentration (f-Hb) thresholds are used to guide subsequent investigation. We established the distributions of f-Hb in a large screening population by sex, age, deprivation and geography. Methods Single estimates of f-Hb were documented for all individuals participating in the first 18 months of the Scottish Bowel Screening Programme (SBoSP). The distributions of f-Hb were generated for all participants, all men and women, and men and women by age quintile and deprivation quintile. Distributions were also generated by geographical region for all participants, men and women, and by deprivation. Comparisons of f-Hb distributions with those found in a pilot evaluation of FIT and three other countries were performed. Results f-Hb was documented for 887,248 screening participants, 422,385 men and 464,863 women. f-Hb varied by sex, age, deprivation quintile and geographical region. The f-Hb distributions by sex and age differed between the SBoSP and the pilot evaluation and the three other countries. Conclusions f-Hb is higher in men than in women and increases with age and deprivation in both sexes. f-Hb also varies by geographical region, independently of deprivation, and by country. The f-Hb distribution estimated by pilot evaluation may not represent the population distribution. Decision limits have advantages over reference intervals. Use of partitioned f-Hb thresholds for further investigation, based on the data generated, has advantages and disadvantages, as do risk scores based on a spectrum of influencing variables.

Faecal haemoglobin can define risk of colorectal neoplasia at surveillance colonoscopy in patients at increased risk of colorectal cancer.

BACKGROUND: Quantitative faecal immunochemical tests measure faecal haemoglobin concentration (f-Hb), which increases in the presence of colorectal neoplasia. OBJECTIVE: We examined the diagnostic accuracy of faecal immunochemical test (FIT)in patients at increased risk of colorectal cancer (CRC) attending for surveillance colonoscopy as per national guidelines. METHODS: A total of 1103 consecutive patients were prospectively invited to complete a FIT before their scheduled colonoscopy in two university hospitals in 2014- 2016. F-Hb was analysed on an OC-Sensor io automated analyser (Eiken Chemical Co., Ltd, Tokyo, Japan) with a limit of detection of 2 µg Hb/g faeces. The diagnostic accuracy of f-Hb for CRC and higher-risk adenoma was examined. RESULTS: A total of 643 patients returned a faecal test. After excluding 4 patients with known inflammatory bowel disease, 639 (57.9%) remained in the study: age range: 25-90 years (median: 64 years, interquartile range (IQR): 55-71): 54.6% male. Of 593 patients who also completed colonoscopy, 41 (6.9%) had advanced neoplasia (4 CRC, 37 higher-risk adenoma). Of the 238 patients (40.1%) who had detectable f-Hb, 31 (13.0%) had advanced neoplasia (2 CRC, 29 higher-risk adenoma) compared with 10 (2.8%) in those with undetectable f-Hb (2 CRC, 8 higher-risk adenoma). Detectable f-Hb gave negative predictive values of 99.4% for CRC and 97.2% for CRC plus higher-risk adenoma. CONCLUSION: In patients at increased risk of CRC under colonoscopy surveillance, a test measuring faecal haemoglobin can provide an objective estimate of the risk of advanced neoplasia, and could enable tailored scheduling of colonoscopy.

Appraisal of the faecal haemoglobin, age and sex test (FAST) score in assessment of patients with lower bowel symptoms: an observational study.

BACKGROUND: Many patients present in primary care with lower bowel symptoms, but significant bowel disease (SBD), comprising colorectal cancer (CRC), advanced adenoma (AA), or inflammatory bowel disease (IBD), is uncommon. Quantitative faecal immunochemical tests for haemoglobin (FIT), which examine faecal haemoglobin concentrations (f-Hb), assist in deciding who would benefit from colonoscopy. Incorporation of additional variables in an individual risk-score might improve this approach. We investigated if the published f-Hb, age and sex test score (FAST score) added value. METHODS: Data from the first year of routine use of FIT in primary care in one NHS Board in Scotland were examined: f-Hb was estimated using one HM-JACKarc FIT system (Kyowa Medex Co., Ltd., Tokyo, Japan) with a cut-off for positivity ≥10 µg Hb/g faeces. 5660 specimens were received for analysis in the first year. 4072 patients were referred to secondary care: 2881 (70.6%) of these had returned a FIT specimen. Of those referred, 1447 had colonoscopy data as well as the f-Hb result (group A): 2521 patients, also with f-Hb, were not immediately referred (group B). The FAST score was assessed in both groups. RESULTS: 1196 (41.7%) of patients who returned a specimen for FIT analysis had f-Hb ≥10 µg Hb/g faeces. In group A, 252 of 296 (85.1%) with SBD had f-Hb > 10 µg Hb/g faeces, as did 528 of 1151 (45.8%) without SBD. Using a FAST score > 2.12, which gives high clinical sensitivity for CRC, only 1143 would have been referred for colonoscopy (21.0% reduction in demand): 286 of 296 (96.6%) with SBD had a positive FAST score, as did 857 of 1151 (74.5%) without SBD. However, one CRC, five AA and four IBD would have been missed. In group B, although 95.2% had f-Hb < 10 µg Hb/g faeces, 1371 (53.7%) had FAST score ≥ 2.12: clinical rationale led to only 122 of group B completing subsequent bowel investigations: a FAST score > 2.12 was found in 13 of 15 (86.7%) with SBD. CONCLUSIONS: The performance characteristics of the FAST score did not seem to enhance the utility of f-Hb alone. Locally-derived formulae might confer desired benefits.

Impact of introducing a faecal immunochemical test (FIT) for haemoglobin into primary care on the outcome of patients with new bowel symptoms: a prospective cohort study.

OBJECTIVE: To determine whether a faecal immunochemical test (FIT) for faecal haemoglobin concentration (f-Hb) can be safely implemented in primary care as a rule-out test for significant bowel disease (SBD) (colorectal cancer (CRC), higher risk adenoma (HRA) and inflammatory bowel disease (IBD)) when used as an adjunct to the clinical assessment of new bowel symptoms. DESIGN: Single-centre prospective cohort study of all patients who attended primary care and submitted a FIT in the first calendar year of the service beginning December 2015. f-Hb was estimated using HM-JACKarc (Kyowa Medex) with a clinical cut-off of ≥10 µg Hb/g faeces. Incident cases of CRC were verified via anonymised record linkage to the Scottish Cancer Registry. RESULTS: 5422 patients submitted 5660 FIT specimens, of which 5372 were analysed (positivity: 21.9%). 2848 patients were referred immediately to secondary care and three with f-Hb <10 µg/g presented acutely within days with obstructing CRC. 1447 completed colonoscopy in whom overall prevalence of SBD was 20.5% (95 CRC (6.6%), 133 HRA (9.2%) and 68 IBD (4.7%)); 6.6% in patients with f-Hb <10 µg/g vs 32.3% in patients with f-Hb ≥10 µg/g. One CRC was detected at CT colonoscopy. 2521 patients were not immediately referred (95.3% had f-Hb <10 µg/g) of which four (0.2%) later developed CRC. Record linkage identified no additional CRC cases within a follow-up period of 23-35 months. CONCLUSION: In primary care, measurement of f-Hb, in conjunction with clinical assessment, can safely and objectively determine a patient's risk of SBD.

The impact of personalised risk information compared to a positive/negative result on informed choice and intention to undergo colonoscopy following colorectal Cancer screening in Scotland (PERICCS) - a randomised controlled trial: study protocol.

BACKGROUND: In Scotland a new, easier to complete bowel screening test, the Faecal Immunochemical Test (FIT), has been introduced. This test gives more accurate information about an individual's risk of having colorectal cancer (CRC), based on their age and gender, and could lead to fewer missed cancers compared to the current screening test. However, there is no evidence of the effect on colonoscopy uptake of providing individuals with personalised risk information following a positive FIT test. The objectives of the study are: 1) To develop novel methods of presenting personalised risk information in an easy-to-understand format using infographics with involvement of members of the public 2) To assess the impact of different presentations of risk information on informed choice and intention to take up an offer of colonoscopy after FIT 3) To assess participants' responses to receiving personal risk information (knowledge, attitudes to screening/risk, emotional responses including anxiety). METHODS: Adults (age range 50-74) registered on the Scottish Bowel Screening database will be invited by letter to take part. Consenting participants will be randomised to one of three groups to receive hypothetical information about their risk of cancer, based on age, gender and faecal haemoglobin concentration: 1) personalised risk information in numeric form (e.g. 1 in 100) with use of infographics, 2) personalised information described as 'highest', 'moderate' or 'lowest' risk with use of infographics, and 3) as a 'positive' test result, as is current practice. Groups will be compared on informed choice, intention to have a colonoscopy, and satisfaction with their decision. Follow-up semi-structured qualitative interviews will be conducted, by telephone, with a small number of consenting participants (n = 10 per group) to explore the acceptability/readability and any potential negative impact of the risk information, participants' understanding of risk factors, attitudes to the different scenarios, and reasons for reported intentions. DISCUSSION: Proving personalised risk information and allowing patient choice could lead to improved detection of CRC and increase patient satisfaction by facilitating informed choice over when/whether to undergo further invasive screening. However, we need to determine whether/how informed choice can be achieved and assess the potential impact on the colonoscopy service. TRIAL REGISTRATION: The trial is registered on www.isrctn.com on 08/12/2017. Registration no: ISRCTN14254582.

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 < 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 < 0.0005). Conclusion f-Hb provides a good rule-out test for SCD and has significantly higher overall diagnostic accuracy than NG12.

The fecal hemoglobin concentration, age and sex test score: Development and external validation of a simple prediction tool for colorectal cancer detection in symptomatic patients.

Prediction models for colorectal cancer (CRC) detection in symptomatic patients, based on easily obtainable variables such as fecal haemoglobin concentration (f-Hb), age and sex, may simplify CRC diagnosis. We developed, and then externally validated, a multivariable prediction model, the FAST Score, with data from five diagnostic test accuracy studies that evaluated quantitative fecal immunochemical tests in symptomatic patients referred for colonoscopy. The diagnostic accuracy of the Score in derivation and validation cohorts was compared statistically with the area under the curve (AUC) and the Chi-square test. 1,572 and 3,976 patients were examined in these cohorts, respectively. For CRC, the odds ratio (OR) of the variables included in the Score were: age (years): 1.03 (95% confidence intervals (CI): 1.02-1.05), male sex: 1.6 (95% CI: 1.1-2.3) and f-Hb (0-<20 µg Hb/g feces): 2.0 (95% CI: 0.7-5.5), (20-<200 µg Hb/g): 16.8 (95% CI: 6.6-42.0), ≥200 µg Hb/g: 65.7 (95% CI: 26.3-164.1). The AUC for CRC detection was 0.88 (95% CI: 0.85-0.90) in the derivation and 0.91 (95% CI: 0.90-093; p = 0.005) in the validation cohort. At the two Score thresholds with 90% (4.50) and 99% (2.12) sensitivity for CRC, the Score had equivalent sensitivity, although the specificity was higher in the validation cohort (p < 0.001). Accordingly, the validation cohort was divided into three groups: high (21.4% of the cohort, positive predictive value-PPV: 21.7%), intermediate (59.8%, PPV: 0.9%) and low (18.8%, PPV: 0.0%) risk for CRC. The FAST Score is an easy to calculate prediction tool, highly accurate for CRC detection in symptomatic patients.