Lower gastrointestinal symptoms are prevalent among individuals colonoscoped within the Bowel Cancer Screening Programme

Detection of cancers and advanced adenomas in asymptomatic participants in colorectal cancer screening: a cross-sectional study

OBJECTIVES

To assess detection rates for colorectal cancer (CRC) and advanced adenomas in asymptomatic CRC screening participants and bowel symptoms in association with CRC and advanced adenoma.

DESIGN

Cross-sectional study.

SETTING

Two screening centres.

PARTICIPANTS

42 554 men and women, aged 50-74 years, participating in a randomised CRC screening trial. 36 059 participants underwent a sigmoidoscopy (and follow-up colonoscopy if positive sigmoidoscopy) and 6495 underwent a colonoscopy after a positive faecal immunochemical test (FIT).

PRIMARY AND SECONDARY OUTCOME MEASURES

Proportion of asymptomatic participants diagnosed with CRC or advanced adenomas. Prevalence of bowel symptoms (rectal bleeding, change in bowel habits, diarrhoea, constipation, bloating, alternating bowel habits, general symptoms, other bowel symptoms) recorded by the endoscopist and their association with CRC and advanced adenomas.

RESULTS

Among sigmoidoscopy participants, 7336 (20.3%) reported at least one symptom. 120 (60%) out of 200 individuals with screen-detected CRC and 1301 (76.5%) out of 1700 with advanced adenoma were asymptomatic. Rectal bleeding was associated with detection of CRC and advanced adenoma (OR 4.3, 95% CI 3.1 to 6.1 and 1.8, 95% CI 1.5 to 2.1, respectively), while change in bowel habits only with CRC detection (OR 3.8, 95% CI 2.4 to 6.1). Among the FIT positives, 2173 (33.5%) reported at least one symptom. Out of 299 individuals with screen-detected CRC and 1639 with advanced adenoma, 167 (55.9%) and 1 175 (71.7%) were asymptomatic, respectively. Detection of CRC was associated with rectal bleeding (OR 1.8, 95% CI 1.4 to 2.3), change in bowel habits (OR 2.2, 95% CI 1.4 to 3.5) and abdominal pain (OR 1.8, 95% CI 1.2 to 2.7).

CONCLUSIONS

Some bowel symptoms increased the likelihood of being diagnosed with CRC or advanced adenoma. However, the majority of individuals with these findings were asymptomatic. Asymptomatic individuals should be encouraged to participate in CRC screening.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov Identifier: NCT01538550.

High-risk symptoms and quantitative faecal immunochemical test accuracy: Systematic review and meta-analysis

BACKGROUND

The quantitative faecal immunochemical test for haemoglobin (FIT) has been revealed to be highly accurate for colorectal cancer (CRC) detection not only in a screening setting, but also in the assessment of patients presenting lower bowel symptoms. Therefore, the National Institute for Health and Care Excellence has recommended the adoption of FIT in primary care to guide referral for suspected CRC in low-risk symptomatic patients using a 10 µg Hb/g faeces threshold. Nevertheless, it is unknown whether FIT´s accuracy remains stable throughout the broad spectrum of possible symptoms.

AIM

To perform a systematic review and meta-analysis to assess FIT accuracy for CRC detection in different clinical settings.

METHODS

A systematic literature search was performed using MEDLINE and EMBASE databases from inception to May 2018 to conduct a meta-analysis of prospective studies including symptomatic patients that evaluated the diagnostic accuracy of quantitative FIT for CRC detection. Studies were classified on the basis of brand, threshold of faecal haemoglobin concentration for a positive test result, percentage of reported symptoms (solely symptomatic, mixed cohorts) and CRC prevalence (< 2.5%, ≥ 2.5%) to limit heterogeneity and perform subgroup analysis to assess the influence of clinical spectrum on FIT´s accuracy to detect CRC.

RESULTS

Fifteen cohorts including 13073 patients (CRC prevalence 0.4% to 16.8%) were identified. Pooled estimates of sensitivity for studies using OC-Sensor at 10 µg Hb/g faeces threshold (n = 10400) was 89.6% [95% confidence interval (CI): 82.7% to 94.0%). However, pooled estimates of sensitivity for studies formed solely by symptomatic patients (n = 4035) and mixed cohorts (n = 6365) were 94.1% (95%CI: 90.0% to 96.6%) and 85.5% (95%CI: 76.5% to 91.4%) respectively (P < 0.01), while there were no statistically significant differences between pooled sensitivity of studies with CRC prevalence < 2.5% (84.9%, 95%CI: 73.4% to 92.0%) and ≥ 2.5% (91.7%, 95%CI: 83.3% to 96.1%) (P = 0.25). At the same threshold, OC-Sensor® sensitivity to rule out any significant colonic lesion was 78.6% (95%CI: 75.6% to 81.4%). We found substantial heterogeneity especially when assessing specificity.

CONCLUSION

The results of this meta-analysis confirm that, regardless of CRC prevalence, quantitative FIT is highly sensitive for CRC detection. However, FIT ability to rule out CRC is higher in studies solely including symptomatic patients.

Differences in diagnostic activity in general practice and findings for individuals invited to the danish screening programme for colorectal cancer: a population-based cohort study

OBJECTIVE

To investigate the diagnostic activity in general practice and the cumulative incidence of colorectal cancer (CRC) in individuals invited to the Danish national screening programme for CRC.

DESIGN

A historical population-based cohort study.

SETTING

The Danish CRC screening programme and general practice.

SUBJECTS

The 376,198 individuals invited to the Danish CRC screening programme from 1 March to 31 December 2014.

MAIN OUTCOME MEASURES

The diagnostic activity (consultations and haemoglobin measures) in general practice in the year preceding the screening invitation and the cumulated incidence of CRC in the year following the screening invitation.

RESULTS

Screening participants had significantly higher diagnostic activity than non-participants. Individuals with a positive faecal immunochemical test (FIT) had higher diagnostic activity compared to individuals with a negative FIT, and a small increase in the months leading up to the invitation. Individuals with a screen-detected CRC had lower diagnostic activity than individuals with no CRC. In total, 308 (25.3%) of CRCs diagnosed in the invited population were diagnosed outside the screening programme. Non-participants with CRC more often had low socio-economic status, high comorbidity and stage IV CRC than participants with CRC.

CONCLUSIONS

There was a tendency that participants and those with a positive FIT had a higher diagnostic activity the year before the screening. This was not seen for those with CRC detected through screening. CRC must still be diagnosed in general practice in the invited population and non-participants are of special interest as they have higher risk of late stage CRC. Key Points Current awareness:Individuals with colorectal cancer (CRC) in screening may be symptomatic and CRC may still occur outside screening in the invited population. Most important points:The majority of individuals with CRC in screening cannot be expected to be diagnosed on symptomatic presentation in general practice GPs have to be aware that CRC still occurs outside screening in the invited population Non-participants with CRC are often deprived and have late stage CRC.

Diagnostic value of rectal bleeding in predicting colorectal cancer: a systematic review

This study aimed at summarizing published study findings on the diagnostic value of rectal bleeding (RB) and informing clinical practice, preventive interventions and future research areas. We searched Medline and Embase for studies published by September 13, 2013 examining the risk of colorectal cancer in patients with RB using highly inclusive algorithms. Data for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and positive predictive value (PPV) of RB were extracted by two researchers and analyzed applying Meta-Disc (version 1.4) and Stata (version 11.0). Methodological quality of studies was assessed according to QUADAS. A total of 38 studies containing 5,626 colorectal cancer patients and 73,174 participants with RB were included. The pooled sensitivity and specificity were 0.47 (95% CI: 0.45-0.48) and 0.96 (95% CI: 0.96-0.96) respectively. The overall PPVs ranged from 0.01 to 0.21 with a pooled value of 0.06 (95% CI: 0.05-0.08). Being over the age of 60 years, change in bowel habit, weight loss, anaemia, colorectal cancer among first-degree relatives and feeling of incomplete evacuation of rectum appeared to increase the predictive value of RB. Although RB greatly increases the probability of diagnosing colorectal cancer, it alone may not be sufficient for proposing further sophisticated investigations. However, given the high specificity, subjects without RB may be ruled out of further investigations. Future studies should focus on strategies using RB as an "alarm" symptom and finding additional indications to justify whether there is a need for further investigations.

Screen-detected colorectal cancers are associated with an improved outcome compared with stage-matched interval cancers

Background:

Colorectal cancers (CRCs) detected through the NHS Bowel Cancer Screening Programme (BCSP) have been shown to have a more favourable outcome compared to non-screen-detected cancers. The aim was to identify whether this was solely due to the earlier stage shift of these cancers, or whether other factors were involved.

Methods:

A combination of a regional CRC registry (Northern Colorectal Cancer Audit Group) and the BCSP database were used to identify screen-detected and interval cancers (diagnosed after a negative faecal occult blood test, before the next screening round), diagnosed between April 2007 and March 2010, within the North East of England. For each Dukes' stage, patient demographics, tumour characteristics, and survival rates were compared between these two groups.

Results:

Overall, 322 screen-detected cancers were compared against 192 interval cancers. Screen-detected Dukes' C and D CRCs had a superior survival rate compared with interval cancers (P=0.014 and P=0.04, respectively). Cox proportional hazards regression showed that Dukes' stage, tumour location, and diagnostic group (HR 0.45, 95% CI 0.29–0.69, P<0.001 for screen-detected CRCs) were all found to have a significant impact on the survival of patients.

Conclusions:

The improved survival of screen-detected over interval cancers for stages C and D suggest that there may be a biological difference in the cancers in each group. Although lead-time bias may have a role, this may be related to a tumour's propensity to bleed and therefore may reflect detection through current screening tests.

Developing a clinical research network: the Northern Region Endoscopy Group experience

Research is central to the National Health Service. Clinical trial recruitment has been aided by the National Institute for Health Research's Comprehensive Research Network but these networks do not support development of research. The Northern Region Endoscopy Group (NREG) was founded in 2007, encompasses 17 endoscopy units and has become a highly successful collaborative research network. The network is now a major contributor to UK trials, has published over 20 papers (>60 abstracts) and holds grants totalling more than £1.5 million. The NREG provides an exemplar model of how collaborative working can contribute significantly to biomedical research.

Non-neoplastic findings at colonoscopy after positive faecal occult blood testing: Data from the English Bowel Cancer Screening Programme

Background

The aim of the English Bowel Cancer Screening Programme (BCSP) is to diagnose early colorectal cancer and advanced adenomas. However, other findings are also reported at screening colonoscopy. Small studies demonstrate findings other than cancer or adenomas (non-neoplastic findings (NNF)) in 11–25%.

Objectives and setting

Describe the frequency and nature of NNF within the BSCP.

Methods

Data were obtained from the BCSP national database for all individuals undergoing colonoscopic investigation after positive faecal occult blood testing between August 2006 and November 2011. Data included demographics, smoking status, neoplastic findings and NNF.

Results

121728 colonoscopies were analysed. ≥1 NNF were found in 26251 cases (21.6%). Diverticular disease (18875 cases) and haemorrhoids (7011) were the most frequently reported. Inflammatory bowel disease (IBD) was reported in 2152 cases. Individuals with a neoplastic diagnosis were less likely to have an NNF than those without (19.8% v 24.4%, p < 0.001). After adjustment for confounding using multivariable analysis, older age was still associated with a small but statistically significant risk of NNF.

Conclusions

The BCSP generates a significant volume of NNF. A small proportion of individuals were found to have inflammatory bowel disease (IBD) - an important diagnosis with implications for long-term management. BCSP participants should be aware that findings other than neoplasia may be detected and the relevance of these findings to that individual is not known. Reporting of NNF varies between colonoscopists, and potential underreporting is a limitation of this study. Further study is required to establish the impact of NNF on primary and secondary care.

Two-week wait symptoms are prevalent in screened patients with a positive faecal occult blood test but do not predict cancer

AIM

Lower gastrointestinal (LGI) symptoms are prevalent in patients screened for bowel cancer yet do not predict a finding of cancer. This study evaluates symptoms in patients with these characteristics against the 2-week wait (2ww) criteria to determine whether they predicted cancer in these patients.

METHOD

A prospective cohort study was performed. Patients with a positive faecal occult blood (FOB) test attending our unit over a 7-month period were included. Data on symptom prevalence, frequency and duration were collected and assessed against the 2ww criteria. Associations between symptom prevalence and patient outcome were investigated using the χ(2) test.

RESULTS

Three hundred and ninety-seven patients were included and 37 (9%) were found to have colorectal cancer (CRC). The prevalence of undefined LGI symptoms was 71% and appeared comparable between those with and without CRC (65 vs 72%, P = 0.385). 2ww symptoms were reported in 147 (37%), with 2ww change in bowel habit in 10% and 2ww rectal bleeding in 31%. 2ww symptom prevalence was similar in those with and without cancer (38 vs 37%, P = 0.915). No significant differences in overall 2ww prevalence or prevalence of individual 2ww symptoms were demonstrated between those with a normal colonoscopy or one showing cancer, polyps or other pathology. Twenty nine per cent of patients with 2ww symptoms had reported these to their GP.

CONCLUSION

Undefined LGI symptoms are prevalent in FOB-positive patients but do not predict CRC. 2ww symptoms are also highly prevalent, yet similarly fail to predict cancer. Further efforts to increase public awareness of cancer symptoms are required, whilst false reassurance from a negative FOB result should be discouraged.