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.

Sex variation in colorectal cancer mortality: trends and implications for screening

BACKGROUND

Colorectal cancer (CRC) screening using faecal tests reduces disease-specific mortality. To investigate mortality and its association with sex, rates in women and men, and in different age ranges, were examined, before and after screening began in Scotland.

METHODS

From 1990-99, no structured screening existed. Three pilots ran from 2000 to 2007 and subsequent full roll-out completed in 2009. Crude mortality rates for 1990-2020 were calculated relative to Scottish population estimates, and age-sex standardized rates calculated for all, pre-screening (<50 years), screening (5-74 years) and post-screening (>74 years) age ranges.

RESULTS

CRC mortality declined from 1990 to 2020, but not linearly, and differed between sexes. In women, 1990-99 showed a steady decline [average annual percentage change (AAPC): -2.1%, 95% confidence interval (CI): -2.8% to -1.4%], but a less marked decline after 2000 (AAPC: -0.7%, 95% CI: -0.9% to -0.4%). In men, no clear decline was seen from 1990 to 1999 (AAPC: -0.4%, 95% CI: -1.1% to 0.4%), but mortality declined from 2000 to 2020 (AAPC: -1.7%, 95% CI: -1.9% to -1.5%). This pattern was exaggerated in the screening age ranges. For 2000-20, the overall reduction in mortality was less in women and in the screening age range. In the post-screening age range, reductions were smaller, but an increase was seen in the pre-screening age range, greater in women.

CONCLUSIONS

CRC mortality fell during 1990-2020, but the decline differed markedly between sexes, indicating a larger beneficial effect of screening on CRC mortality in men compared to women: use of different thresholds for the sexes might lead to equality.

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.

Comparison with first round findings of faecal haemoglobin concentrations and clinical outcomes in the second round of a biennial faecal immunochemical test based colorectal cancer screening programme

Objective

How faecal haemoglobin concentrations (f-Hb) vary from one round to the next in a colorectal cancer (CRC) screening programme, and relate to colonoscopy findings, are unknown. Our aim was to use data from the first two rounds of the faecal immunochemical test (FIT) based Scottish Bowel Screening Programme (SBoSP) to explore these issues.

Methods

Faecal haemoglobin concentration (f-Hb) percentiles in the second round were compared with those in the first when the first round yielded a negative FIT result (<80 µg Hb/g faeces), a positive FIT but no colonoscopy, CRC, all adenoma, and a negative colonoscopy. In addition, the outcomes in the first and second rounds were compared.

Results

The profiles of f-Hb in the first and second rounds differed in (a) those who had had a negative FIT result in the first round and (b) those in whom neoplastic pathology had been found. In contrast, the pattern of difference between profiles in those who had had a negative colonoscopy was very similar to that in those in whom an adenoma had been found. In addition, the risk of CRC being diagnosed in the second round after a negative colonoscopy in the first was 3.0%, not very different to that after a negative test result (4.9%).

Conclusions

Adenomas may be rarely the cause of a positive FIT result. An alternative explanation as to why these are detected using FIT is required. In addition, a negative colonoscopy for a positive FIT result does not rule out the finding of significant neoplastic pathology in the next round.

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 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.

The use of faecal haemoglobin in deciding which patients presenting to primary care require further investigation (and how quickly) - the FIT approach

Patients presenting to general practitioners (GPs) with new bowel symptoms can be difficult to assess since symptoms are poor predictors of pathology. National Institute for Health and Care Excellence referral guidelines highlight features that may suggest colorectal cancer (CRC) including rectal bleeding, palpable mass, iron deficiency anaemia, but also non-specific symptoms such as weight loss. In those patients referred for investigation on the basis of symptoms alone the yield of CRC is low (2-3%). Faecal immunochemical tests (FIT) quantify faecal haemoglobin (f-Hb) and are widely used in bowel screening programmes. A number of groups have now studied the utility of FIT in patients attending primary care with new bowel symptoms. Studies have concluded that if the FIT is negative and clinical assessment and full blood count normal then the risk of underlying significant bowel disease (SBD) is extremely small. Furthermore, patients with f-Hb ≥400 μgHb/g faeces have >50% risk of SBD and should be investigated urgently. Thus, a single f-Hb requested by GPs provides both a reliable prediction of the absence of SBD, and an objective assessment of the need and urgency of further investigation.

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 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.

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

OBJECTIVE

Faecal 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.

DESIGN

Data 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).

RESULTS

Overall, 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.

CONCLUSION

Transition 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%.

Variation in changes in the incidence of colorectal cancer by age and association with screening uptake: an observational study

OBJECTIVES

In developed countries, the incidence of colorectal cancer (CRC) has declined in the over 50 years age group but increased in younger people. We studied CRC incidence by age and the influence of screening uptake.

DESIGN

Age-standardised and sex-standardised incidences for CRC from 1997 to 2017 were obtained from the Scottish Cancer Registry (SCR). In addition, linkage between the Scottish Bowel Screening Database and the SCR allowed investigation of any association between screening participation and CRC incidence.

SETTING

Scotland and the Scottish Bowel Screening Programme, in which guaiac faecal occult blood test screening was piloted from March 2000 and fully rolled by December 2009.

PARTICIPANTS

From the introduction of screening in 2000 through to 2017, 2 395 172 were invited to participate, of whom 1 487 999 participated at least once.

MAIN OUTCOME MEASURES

Incidence of CRC.

RESULTS

In the screening age range (50-74 years), CRC incidence peaked at 156.5 cases per 100 000 in 2010 after full roll-out of screening across Scotland but fell to 123.9 per 100 000 in 2017. However, under 50 years, there was a rise from 5.3 cases per 100 000 in 2000 to 6.8 per 100 000 in 2017. When CRC incidence was examined in those who had been offered screening, incidence fell in the participant group more than in the non-participant group after roll-out of screening was complete. Analysis of cumulative incidence demonstrated that CRC incidence in the participant group remained consistently below that of the non-participant from around 7 years of follow-up.

CONCLUSIONS

The incidence of CRC in Scotland has declined in the over 50 years age group but increased in younger people. It is likely that population screening has contributed to the reduction in CRC incidence in the over 50 years age group.

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.

Randomized controlled trial: Flexible sigmoidoscopy as an adjunct to faecal occult blood testing in population screening

Objectives

Flexible sigmoidoscopy screening at around age 60 can reduce colorectal cancer incidence. Insufficient evidence exists on flexible sigmoidoscopy at age 60 in a population being offered biennial faecal occult blood test screening from age 50. This randomized controlled trial assessed if flexible sigmoidoscopy would be an effective adjunct to faecal occult blood test.

Methods

In the Scottish Bowel Screening Programme between June 2014 and December 2015, 51,769 individuals were randomized to be offered flexible sigmoidoscopy instead of faecal occult blood test at age 60 or to continue faecal occult blood test. Those not accepting flexible sigmoidoscopy and those with normal flexible sigmoidoscopy were offered faecal occult blood test. All with flexible sigmoidoscopy-detected neoplasia or a positive faecal occult blood test result were offered colonoscopy.

Results

Overall flexible sigmoidoscopy uptake was 17.8%, higher in men than women, and decreased with increasing deprivation (25.7% in the least to 9.2% in the most deprived quintile). In those who underwent flexible sigmoidoscopy, detection rate for colorectal cancer was 0.13%, for adenoma 7.27%, and for total neoplasia 7.40%. In those who underwent colonoscopy after a positive flexible sigmoidoscopy, detection rate for colorectal cancer was 0.28%, adenoma 8.66%, and total neoplasia 8.83%. On an intention to screen basis, there was no difference in colorectal cancer detection rate between the study and control groups. Adenoma and total neoplasia detection rate were significantly higher in the study group, with odds ratios of 5.95 (95%CI: 4.69–7.56) and 5.10 (95%CI: 4.09–6.35), respectively.

Conclusions

In a single screening round at age 60, there was low uptake and neoplasia detection rate. Flexible sigmoidoscopy detected significantly more neoplasia than faecal occult blood test alone.

Changes in prevalence of faecal occult blood positivity over time

Objectives

Changes in the prevalence of faecal occult blood test positivity over time have not been previously reported, but could have important implications. This study examined the positivity of the initial guaiac faecal occult blood test, a surrogate marker for colorectal bleeding, in participants aged 50 in a national bowel screening programme.

Methods

Data from the Scottish Bowel Screening Programme were used to study the initial positivity of the guaiac faecal occult blood test between 2007 and 2017. Positive predictive values of the testing process for colorectal cancer and adenoma were assessed over the same time period.

Results

Across Scotland, the initial guaiac faecal occult blood test positivity increased from 4.1 to 10.8%. In NHS Grampian and NHS Fife, two of the three NHS Boards which began roll-out of screening in 2007, it increased from 4.0 to 10.9%. In the Scottish Bowel Screening Programme, the positive predictive value declined from 11.0 to 6.6% for colorectal cancer and increased from 31.6 to 39.8% for adenoma.

Conclusions

In the Scottish programme over a decade, initial guaiac faecal occult blood test positivity increased in participants aged 50. This may be associated with changes in lifestyle and might have implications for screening clinical outcomes, including positive predictive value.

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.

Do other variables add value to assessment of the risk of colorectal disease using faecal immunochemical tests for haemoglobin?

Background

Faecal immunochemical tests for haemoglobin have been recommended to assist in assessment of patients presenting in primary care with lower bowel symptoms. The aim was to assess if, and which, additional variables might enhance this use of faecal immunochemical tests.

Methods

Faecal immunochemical test analysis has been a NHS Tayside investigation since December 2015. During the first year, 993 patients attending colonoscopy were invited to complete a detailed questionnaire on demographic background, symptoms, smoking status, alcohol use, dietary fibre, red and processed meat intake, physical activity, sitting time, dietary supplement use, family history of colorectal cancer, adenoma, inflammatory bowel disease and diabetes. Significant bowel disease was classified as colorectal cancer, advanced adenoma or inflammatory bowel disease.

Results

A total of 470 (47.3%) invitees agreed to complete the questionnaire and 408 (41.1%) did. Unadjusted odds ratios for the presence of significant bowel disease compared with undetectable faecal haemoglobin increased with increasing faecal haemoglobin and for faecal haemoglobin 10–49, 50–199, 200–399 and ⩾400 μg Hb/g faeces were 0.95 (95% CI: 0.16–5.63), 2.47 (0.55–1.03), 6.30 (1.08–36.65) and 18.90 (4.22–84.62), respectively. Rectal bleeding and family history of polyps were the only other variables with statistically significant ( P < 0.05) odds ratios greater than 1.00, being 1.88 (1.13–3.17) and 2.93 (1.23–6.95), respectively. Odds ratios adjusted for all other variables showed similar associations, but only faecal haemoglobin and family history of polyps had significant associations.

Conclusions

Faecal haemoglobin is the most important factor to be considered when deciding which patients presenting in primary care with lower bowel symptoms would benefit most from referral for colonoscopy.

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.

Faecal haemoglobin and faecal calprotectin as indicators of bowel disease in patients presenting to primary care with bowel symptoms

OBJECTIVE

In primary care, assessing which patients with bowel symptoms harbour significant disease (cancer, higher-risk adenoma or IBD) is difficult. We studied the diagnostic accuracies of faecal haemoglobin (FHb) and faecal calprotectin (FC) in a cohort of symptomatic patients.

DESIGN

From October 2013 to March 2014, general practitioners were prompted to request FHb and FC when referring patients with bowel symptoms to secondary care. Faecal samples were analysed for haemoglobin (EIKEN OC-Sensor io) and calprotectin (BÜHLMANN Calprotectin ELISA). Patients triaged to endoscopy were investigated within 6 weeks. All clinicians and endoscopists were blind to the faecal test results. The diagnostic accuracies of FHb and FC for identification of significant bowel disease were assessed.

RESULTS

1043 patients returned samples. FHb was detectable in 57.6% (median 0.4 µg/g, 95% CI 0.4 to 0.8; range 0-200). FC at 50 µg/g or above was present in 60.0%. 755 patients (54.6% women, median age 64 years (range 16-90, IQR 52-73)) returned samples and completed colonic investigations. 103 patients had significant bowel disease; the negative predictive values of FHb for colorectal cancer, higher-risk adenoma and IBD were 100%, 97.8% and 98.4%, respectively. Using cut-offs of detectable FHb and/or 200 µg/g FC detected two further cases of IBD, one higher-risk adenoma and no additional cancers.

CONCLUSIONS

In primary care, undetectable FHb is a good 'rule-out' test for significant bowel disease and could guide who requires investigation.

Clinical outcomes using a faecal immunochemical test for haemoglobin as a first-line test in a national programme constrained by colonoscopy capacity

INTRODUCTION

Because of their many advantages, faecal immunochemical tests (FIT) are superseding traditional guaiac-based faecal occult blood tests in bowel screening programmes.

METHODS

A quantitative FIT was adopted for use in two evaluation National Health Service (NHS) Boards in Scotland using a cut-off faecal haemoglobin concentration chosen to give a positivity rate equivalent to that achieved in the Scottish Bowel Screening Programme. Uptake and clinical outcomes were compared with results obtained contemporaneously in two other similar NHS Boards and before and after the evaluation in the two evaluation NHS Boards.

RESULTS

During the evaluation, uptake was 58.5%. This was higher than in the same NHS Boards both before and after the evaluation, higher than in the other two NHS Boards and higher than the 53.7% achieved overall in Scotland. The overall positivity rate was higher in men than in women and increased with age in both genders. Positive predictive values for cancer (4.8%), high-risk adenoma (23.3%), all adenoma (38.2%) and all neoplasia (43.0%) in the two test NHS Boards were similar in all groups.

CONCLUSIONS

In summary, this evaluation of the FIT supports the introduction of FIT as a first-line test, even when colonoscopy capacity is limited.

Deprivation and faecal haemoglobin: implications for bowel cancer screening

OBJECTIVE

To investigate the relationship between deprivation and faecal haemoglobin concentration (f-Hb).

SETTING

Scottish Bowel Screening Programme.

METHODS

A total of 66725 men and women, aged 50 to 74, were invited to provide a single sample for a faecal immunochemical test. Deprivation was estimated using the Scottish Index of Multiple Deprivation quintiles: f-Hb was measured (OC-Sensor, Eiken, Japan) on 38439 participants. The relationship between deprivation quintiles and f-Hb was examined.

RESULTS

Median age was 60 years, 53.6% women, with 14.1%, 19.7%, 17.7%, 25.9% and 22.6% in the lowest to the highest deprivation quintiles respectively. No detectable f-Hb was found in 51.9%, ranging from 45.5% in the most deprived up to 56.5% in the least deprived. As deprivation increased, f-Hb increased (p < 0.0001). This trend remained controlling for sex and age (p < 0.001). Participants in the most deprived quintile were more likely to have a f-Hb above a cut-off of 80 µg Hb/g faeces compared with the least deprived, independent of sex and age (adjusted odds ratio 1.70, 95% confidence interval: 1.37 to 2.11).

CONCLUSIONS

Deprivation and f-Hb are related. This has important implications for selection of cut-off f-Hb for screening programmes, and supports the inclusion of deprivation in risk-scoring systems.

Use of a faecal immunochemical test narrows current gaps in uptake for sex, age and deprivation in a bowel cancer screening programme

Objectives

To investigate the characteristics of participants screened for bowel cancer using a faecal immunochemical test for haemoglobin (FIT).

Setting

Scottish Bowel Screening Programme.

Methods

65909 men and women in two NHS Boards, aged 50 to 74, were invited to participate in an evaluation of FIT as a first-line test. Uptake was calculated by sex, age in quintiles, and deprivation in quintiles, and compared with a group who had completed a guaiac faecal occult blood test (gFOBT) and for whom details of sex, age and deprivation were well documented.

Results

FIT kits from 38672 participants were tested. The overall uptake of 58.7% was significantly higher than the 53.9% for gFOBT (p < 0.0001). Uptakes in the two NHS Boards were 57.6% and 54.4% for men and 63.2% and 59.1% for women, higher than the 49.5% and 58.1% completing gFOBT. Uptake was higher for FIT than gFOBT in all age and deprivation quintiles for both men and women in both NHS Boards. The difference in uptake fell with age for men but rose for women; the increase in uptake was greater for men than women. Uptake fell as deprivation decreased for both sexes, and was similar in both NHS Boards.

Conclusions

Use of FIT increases uptake over gFOBT, and the greatest increases are seen in men, younger participants, and more deprived individuals, groups for which an increase in uptake is likely to be beneficial. The results support a move to FIT as a first-line screening test for those countries still using gFOBT.

Low faecal haemoglobin concentration potentially rules out significant colorectal disease

AIM

The study aimed to determine whether faecal haemoglobin (Hb) concentration can assist in deciding who with lower abdominal symptoms will benefit from endoscopy.

METHOD

Faecal Hb concentrations were measured on single samples from 280 patients referred for lower gastrointestinal tract endoscopy from primary care in NHS Tayside who completed a faecal immunochemical test (FIT) for Hb and underwent subsequent endoscopy.

RESULTS

Among 739 invited patients, FIT and endoscopy were completed by 280 (median age 63 (18-84) years; 59.6% women), with a median time between FIT and endoscopy of 9 days. Six (2.1%) participants had cancer, 23 (8.2%) had high-risk adenoma (HRA) (more than three adenomas or any > 1 cm), 31 (11.1%) low-risk adenoma (LRA) and 26 (9.3%) inflammatory bowel disease (IBD) as the most serious diagnosis. Those with cancer had a median faecal Hb of > 1000 ng Hb/ml buffer. Those with cancer + HRA + IBD had a median faecal Hb concentration of 75 ng Hb/ml buffer (95% CI 18-204), which was significantly higher than that of all remaining participants without significant colorectal disease (P < 0.0001). Using a cut-off faecal Hb concentration of 50 ng Hb/ml buffer, negative predictive values of 100.0%, 94.4%, 93.4% and 93.9% were found for cancer, HRA, LRA and IBD. Patients with reasons for referral other than rectal bleeding and family history did not have high faecal Hb concentrations.

CONCLUSION

Faecal Hb concentration measurements have considerable potential to contribute to reducing unnecessary endoscopy for the majority of symptomatic patients.

Faecal haemoglobin concentration is related to severity of colorectal neoplasia

AIMS

Guaiac faecal occult blood tests are being replaced by faecal immunochemical tests (FIT). We investigated whether faecal haemoglobin concentration (f-Hb) was related to stage in progression of colorectal neoplasia, studying cancer and adenoma characteristics in an evaluation of quantitative FIT as a first-line screening test.

METHODS

We invited 66 225 individuals aged 50-74 years to provide one sample of faeces. f-Hb was measured on samples from 38 720 responders. Colonoscopy findings and pathology data were collected on the 943 with f-Hb ≥ 400 ng Hb/ml (80 µg Hb/g faeces).

RESULTS

Of the 814 participants with outcome data (median age: 63 years, range 50-75, 56.4% male), 39 had cancer, 190 high-risk adenoma (HRA, defined as ≥ 3 or any ≥ 10 mm) and 119 low-risk adenoma (LRA). 74.4% of those with cancer had f-Hb>1000 ng Hb/ml compared with 58.4% with HRA, and 44.1% with no pathology. Median f-Hb concentration was higher in those with cancer than those with no (p<0.002) or non-neoplastic (p<0.002) pathology, and those with LRA (p=0.0001). Polyp cancers had lower concentrations than more advanced stage cancers (p<0.04). Higher f-Hb was also found in those with HRA than with LRA (p<0.006), large (>10 mm) compared with small adenoma (p<0.0001), and also an adenoma displaying high-grade dysplasia compared with low-grade dysplasia (p<0.009).

CONCLUSIONS

f-Hb is related to severity of colorectal neoplastic disease. This has ramifications for the selection of the appropriate cut-off concentration adopted for bowel screening programmes.

Experience with a two-tier reflex gFOBT/FIT strategy in a national bowel screening programme

Objectives

To evaluate a two-tier reflex guaiac-based faecal occult blood test (gFOBT)/faecal immunochemical test (FIT) algorithm in screening for colorectal cancer.

Setting

Fourth screening round in NHS Tayside (Scotland).

Methods

gFOBT were sent to 50–74-year-olds. Participants with five or six windows positive were offered colonoscopy. Participants with one to four windows positive were sent a FIT and, if positive, were offered colonoscopy. Participants providing an untestable gFOBT were sent a FIT and, if positive, were offered colonoscopy. Outcomes following positive results, cancer stages and key performance indicators were assessed.

Results

Of 131,885 invited, 73,315 (55.6%) responded. There were 66,957 (91.3%) negative, 241 (0.3%) strong positive, 5230 (7.1%) weak positive and 887 (1.2%) untestable results. The 241 participants who had five or six windows positive had more cancers than those positive by other routes: only 3 of the 30 cancers (9.7%) were Dukes' A. Among the 983 positive results from the weak positive gFOBT then positive FIT route, there were fewer cancers and more normal colonoscopies, but more adenomas than in the group with a strong positive gFOBT. In those with an untestable gFOBT, 77 had a positive FIT result, with fewer true and more false positive results than in the other groups. Fewer males had cancer and stages were earlier than in females, but more had adenoma. The detection rate for cancer was 0.18% and the PPV for cancer and all adenomas was 41.3%.

Conclusions

The algorithm and FIT following a weak positive gFOBT have advantages. FIT following an untestable gFOBT warrants review.

Faecal haemoglobin concentrations by gender and age: implications for population-based screening for colorectal cancer

BACKGROUND

Faecal immunochemical tests (FIT) are becoming widely used in colorectal cancer screening. Estimation of faecal haemoglobin concentration in a large group prompted an observational study on gender and age.

METHODS

A single estimate of faecal haemoglobin concentration was made using quantitative automated immunoturbidimetry. Potential reference intervals were calculated for men and women and for age quintiles according to the Clinical and Laboratory Standards Institute Approved Guideline. The percentages of positive results were calculated at a number of concentrations. The percentages of individuals who fell into different risk groups were assessed.

RESULTS

The 97.5 percentiles, potential upper reference limits, were 519 ng haemoglobin/mL (90% CI: 468-575) for men and 283 ng haemoglobin/mL (90% CI: 257-316) for women. Concentrations increased with age in both genders. Decision limits have advantages over reference intervals. At any cut-off concentration, more men are declared positive than women and more older people are declared positive than younger people. Future risk of neoplasia is higher in men than in women and in older people.

CONCLUSIONS

Faecal haemoglobin concentrations vary with gender and age. More tailored strategies are needed in screening programmes. Faecal haemoglobin concentration could be included in individual risk assessment scores. These data should assist in screening programme design.

Autosomal glycogenosis of liver and muscle due to phosphorylase kinase deficiency is caused by mutations in the phosphorylase kinase beta subunit (PHKB)

Glycogen storage disease due to phosphorylase kinase deficiency occurs in several variants that differ in mode of inheritance and tissue-specificity. This heterogeneity is suspected to be largely due to mutations affecting different subunits and isoforms of phosphorylase kinase. The gene of the ubiquitously expressed beta subunit, PHKB, was a candidate for involvement in autosomally transmitted phosphorylase kinase deficiency of liver and muscle. To identify such mutations, the complete PHKB coding sequence was amplified by RT-PCR of RNA isolated from blood samples of patients and analyzed by direct sequencing of PCR products. The characterization of mutations was complemented by PCR of genomic DNA. In one female and four male patients, we identified five independent nonsense mutations (Y418ter; R428ter; Y974H+E975ter; Q656ter in two cases), one single-base insertion in codon N421, one splice-site mutation affecting exon 31, and a large deletion involving the loss of exon 8. Although these severe translation-disrupting mutations occur in constitutively expressed sequences of the only known beta subunit gene of phosphorylase kinase, PHKB, they are associated with a surprisingly mild clinical phenotype, affecting virtually only the liver, and relatively high residual enzyme activity of approximately 10%.

Pain during injection of propofol. The effect of prior administration of thiopentone

A controlled, double-blind study was performed to compare the prior administration of intravenous saline 4 ml (n = 36), lignocaine 20 mg (n = 36) or thiopentone 100 mg (n = 43) on the pain produced by intravenous injection of propofol. One hundred and fifteen ASA 1 or 2 patients scheduled for minor surgery were studied using a randomised, double-blind design. Thiopentone was more effective than lignocaine in reducing the incidence of propofol injection pain (p < 0.03).