The risk of colorectal cancer with symptoms at different ages and between the sexes: a case-control study

Diagnostic yield from symptomatic lower gastrointestinal endoscopy in the UK: A British Society of Gastroenterology analysis using data from the National Endoscopy Database

BACKGROUND

The value of lower gastrointestinal endoscopy (LGIE; colonoscopy or sigmoidoscopy) relates to its ability to detect clinically relevant findings, predominantly cancers, preneoplastic polyps or inflammatory bowel disease. There are concerns that many LGIEs are performed on low-risk patients with limited benefit.

AIMS

To determine the diagnostic outcomes of LGIE for common symptoms.

METHODS

We performed a cross-sectional study of diagnostic LGIE between March 2019 and February 2020 using the UK National Endoscopy Database. We used mixed-effects logistic regression models, incorporating random (endoscopist) and fixed (symptoms, patient age, and sex) effects upon two dependent variables (large polyp [≥10 mm] and cancer diagnosis). Adjusted positive predictive values (aPPVs) were calculated.

RESULTS

We analysed 384,510 LGIEs; 33.2% were performed on patients aged under 50 and 53.6% on women. Regarding colonoscopies, the unadjusted PPV for cancer was 1.5% (95% CI: 1.4-1.5); higher for men than women (1.9% vs. 1.1%, p < 0.01). The PPV for large polyps was 3.2% (95% CI: 3.1-3.2). The highest colonoscopy cancer aPPVs were in the over 50s (1.9%) and in those with rectal bleeding (2.5%) or anaemia (2.1%). Cancer aPPVs for other symptoms were <1% despite representing 54.3% of activity. In patients under 50, aPPVs were 0.4% for cancer and 1.6% for large polyps. Results were similar for sigmoidoscopy.

CONCLUSIONS

Most colonoscopies were performed on patients with low-risk symptoms, where cancer risk was similar to the general population. Cancer and large polyp yield was highest in elderly patients with rectal bleeding or anaemia, although still fell short of FIT-based screening yields.

Stage-specific risk of colon and rectal cancer in patients presenting with rectal bleeding or change in bowel habit in primary care: A population-based cohort study

INTRODUCTION

Rectal bleeding and change in bowel habit are red-flag symptoms for colon and rectal cancer but how they relate to advanced stage disease is not adequately understood.

METHODS

We analysed primary care electronic health records data on patients aged 30-99 years. Using logistic regression, we first examined the risk of colon and rectal cancer within 12 months in patients presenting with change in bowel habit and rectal bleeding, and then the risk of advanced stage at diagnosis within cancer cases. We combined the results to estimate risk of advanced stage colon and rectal cancers at diagnosis.

RESULTS

For both symptoms and sexes, risk of cancer (overall and by stage) increased with increasing age. We illustrate the findings for persons at the highest age-specific observed risk (typically aged around 80). In men, change in bowel habit (CIBH) and rectal bleeding were associated with different risk of advanced stage colon and rectal cancers (e.g., for colon, CIBH = 2.7% (95% CI 2.2-3.1) and rectal bleeding = 1.7% (95% CI 1.4-2.0)), but without evidence of risk difference between the two symptoms for non-advanced disease. The opposite pattern was apparent in women, with both symptoms associated with similar risk of advanced disease, but different risk of non-advanced colon and rectal cancers (e.g., for colon, CIBH = 1.0% (95% CI 0.8-1.3) and rectal bleeding = 1.3% (95% CI 1.1-1.6)).

DISCUSSION

Change in bowel habit and rectal bleeding have different age-specific associations with advanced stage disease, which vary by sex. A substantial proportion of cases is diagnosed at non-advanced stage, supporting the need for prompt diagnostic assessment of patients who present with those symptoms, taking into account the age-specific nature of risks.

Colorectal cancer in symptomatic patients: How to improve the diagnostic pathway

Even in countries with national screening programmes for colorectal cancer, most cancers are identified after the patient has developed symptoms. The patients present these symptoms usually to primary care, or in some countries to specialist care. In either healthcare setting, the clinician has to consider cancer to be a possibility, then to perform triage investigations, followed by definitive investigation, usually by colonoscopy. This apparently simple pathway is not simple: most symptoms of colorectal cancer are more likely to represent benign disease than cancer, and each of these stages represents selection of patients into a higher-risk pool. This article summarises a symptom-based approach to selection and initial investigation of such patients in primary care. Some special groups need particular attention, including the younger patient, those with an inherited predisposition to cancer, and those with co-morbidities.

Prediction of advanced colorectal neoplasia based on metabolic parameters among symptomatic patients

BACKGROUND AND AIM

Worldwide, colorectal cancer (CRC) is the third most common cancer and ranks second among the leading causes of cancer death. This study aims to devise and validate a scoring system based on metabolic parameters to predict the risk of advanced colorectal neoplasia (ACN) in a large Chinese population.

METHODS

This was a cohort study of 495 584 symptomatic subjects aged 40 years or older who have received colonoscopy in Hong Kong from 1997 to 2017. The algorithm's discriminatory ability was evaluated as the area under the curve (AUC) of the mathematically constructed receiver operating characteristic curve.

RESULTS

Age, male gender, inpatient setting, abnormal aspartate transaminase/alanine transaminase, white blood cell, plasma gamma-glutamyl transferase, high-density lipoprotein cholesterol, triglycerides, and hemoglobin A1c were significantly associated with ACN. A scoring of < 2.65 was designated as "low risk (LR)." Scores at 2.65 or above had prevalence higher than the overall prevalence and hence were assigned as "high risk (HR)." The prevalence of ACN was 32% and 11%, respectively, for HR and LR groups. The AUC for the risk score in the derivation and validation cohort was 70.12%.

CONCLUSIONS

This study has validated a simple, accurate, and easy-to-use scoring algorithm, which has a high discriminatory capability to predict ACN in symptomatic patients. Future studies should examine its predictive performance in other population groups.

Development and Validation of Risk Prediction Models for Colorectal Cancer in Patients with Symptoms

We aimed to develop and validate prediction models incorporating demographics, clinical features, and a weighted genetic risk score (wGRS) for individual prediction of colorectal cancer (CRC) risk in patients with gastroenterological symptoms. Prediction models were developed with internal validation [CRC Cases: n = 1686/Controls: n = 963]. Candidate predictors included age, sex, BMI, wGRS, family history, and symptoms (changes in bowel habits, rectal bleeding, weight loss, anaemia, abdominal pain). The baseline model included all the non-genetic predictors. Models A (baseline model + wGRS) and B (baseline model) were developed based on LASSO regression to select predictors. Models C (baseline model + wGRS) and D (baseline model) were built using all variables. Models' calibration and discrimination were evaluated through the Hosmer-Lemeshow test (calibration curves were plotted) and C-statistics (corrected based on 1000 bootstrapping). The models' prediction performance was: model A (corrected C-statistic = 0.765); model B (corrected C-statistic = 0.753); model C (corrected C-statistic = 0.764); and model D (corrected C-statistic = 0.752). Models A and C, that integrated wGRS with demographic and clinical predictors, had a statistically significant improved prediction performance. Our findings suggest that future application of genetic predictors holds significant promise, which could enhance CRC risk prediction. Therefore, further investigation through model external validation and clinical impact is merited.

Possible Value of Faecal Immunochemical Test (FIT) When Added in Symptomatic Patients Referred for Colonoscopy: A Systematic Review

If Colorectal cancer (CRC) is detected and treated early, the survival rate is high. This is one of the reasons that population-based screening programs for the early detection of CRC using the faecal immunochemical test (FIT) started worldwide. These programs compete with regular colonoscopy programs and increase the waiting time for symptomatic patients. However, the literature has shown that the correlation between intestinal complaints and the gain of colonoscopy is poor. The aim of this study is to assess the diagnostic utility of symptoms for the yield (CRC) of colonoscopy and to compare this with the diagnostic utility of FIT when offered to symptomatic patients. Methods: We performed a systematic review search for CRC as an outcome of colonoscopy in referred symptomatic patients and separately for CRC as an outcome in symptomatic patients with a positive FIT. We searched systematically for clinical trials or observational studies in databases, followed by hand-searching of reference lists. We used random Meta-Disc to evaluate the diagnostic performance, using the exploration of heterogeneity with a variety of test statistics and by computing the pooled estimates. Results: We included 35 studies, with almost 5 million symptomatic patients. In addition, we included nine prospective studies with a positive FIT in symptomatic patients, with more than 5000 patients. Significant heterogeneity was found for every symptom and the outcome of colonoscopy in the effect size of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio. In a random effect model, the pooled sensitivity of colonoscopy in symptomatic patients was very low (25%). However, the pooled sensitivity in symptomatic patients with a positive FIT was 83% and the pooled specificity 77%. A total of 75 symptomatic patients (1.4%) had a false-negative FIT. Conclusion: Adding FIT in symptomatic patients seems useful for predicting CRC as an outcome of colonoscopy. FIT seems a potential tool for an improved triage of colonoscopy in symptomatic patients.

Use of faecal immunochemical tests common in patients with suspected colorectal cancer but unrelated to travel distance to secondary care: a population-based study from Swedish primary care

BACKGROUND

Evidence is increasing for the use of faecal immunochemical tests (FITs) for occult blood as diagnostic tools when colorectal cancer can be suspected. FITs have been used for this purpose in Swedish primary care since around 2005 despite absence of supporting guidelines. To our knowledge, the extent of this use has not been studied.

OBJECTIVE

To investigate the use of FITs as diagnostic tools, and if the use was related to patient age, sex and travel time from primary care to diagnostic facilities in secondary care.

DESIGN

Population-based retrospective study using data from electronic health records.

SETTING AND SUBJECTS

Patients ≥18 years that provided FITs in primary care in five Swedish health care regions during 2015. Driving times from their primary care centres to secondary care were calculated.

MAIN OUTCOME MEASURES

The proportion of patients that provided FITs was calculated for each region, different age intervals and grouped driving times.

RESULTS

18,913 patients provided FITs. The proportion of listed patients in the five regions that provided FITs increased with age: 0.86-1.2% for ages <65 years, 3.6-4.1% for ages 65-79 years and 3.8-6.1% for ages ≥80 years. Differences between the regions were small. There was no overall correlation between the proportion of patients that provided FITs and driving time to secondary care.

CONCLUSION

FITs were used extensively in Swedish primary care with a higher use in older age groups. There was no tendency towards a higher use of FITs at primary care centres with longer driving times to secondary care.Key PointsEvidence is increasing for the use of faecal immunochemical tests (FITs) as diagnostic tools when colorectal cancer can be suspected. We investigated the use of FITs in Sweden.FITs were used extensively in primary care especially in older age groups.There were small differences in the use of FITs between five studied health care regions.There was no tendency towards a higher use of FITs at primary care centres with longer driving times to diagnostic facilities in secondary care.

The association between sociodemographic factors and time to diagnosis for colorectal cancer in northern Sweden

OBJECTIVES

This study examined whether sociodemographic factors, including distance to hospital, were associated with differences in the diagnostic interval and the treatment interval for colorectal cancer in northern Sweden.

METHODS

Data were retrieved from the Swedish cancer register on patients (n = 446) diagnosed in three northern regions during 2017-2018, then linked to data from Statistics Sweden and medical records. Also, Google maps was used to map the distance between patients' place of residence and nearest hospital. The different time intervals were analysed using Mann-Whitney U-test and Cox regression.

RESULTS

Differences in time to diagnosis were found between groups for income and distance to hospital, favouring those with higher income and shorter distance. The unadjusted regression analysis showed higher income to be associated with more rapid diagnosis (HR 1.004, CI 1.001-1.007). This association remained in the fully adjusted model for income (HR 1.004, CI 1.000-1.008), but not for distance. No differences between sociodemographic groups were found in the treatment interval.

CONCLUSION

Higher income and shorter distance to hospital were in the unadjusted models associated with shorter time to diagnosis for patients with CRC in northern Sweden. The association remained for income when adjusting for other variables even though the difference was small.

Cultivating Doctors' Gut Feeling: Experience, Temporality and Politics of Gut Feelings in Family Medicine

For the past decade, within family medicine there has been a focus on cultivating doctors gut feelings as 'a way of knowing' in cancer diagnostics. In this paper, building on interviews with family doctors in Oxford shire, UK we explore the embodied and temporal dimensions of clinical reasoning and how the cultivation of doctors' gut feelings is related to hierarchies of medical knowledge, professional training, and doctors' fears of litigation. Also, we suggest that the introduction of gut feeling in clinical practice is an attempt to develop a theory of clinical reasoning that fits the biopolitics of our contemporary. The turn towards predictive medicine and the values introduced by accelerated diagnostic regimes, we conclude, introduce a need for situated and embodied modes of reading bodies. We contribute theoretically by framing our analysis within a sensorial anthropology approach.

The Underestimated and Overlooked Burden of Diarrhea and Constipation in Cancer Patients

PURPOSE OF REVIEW

This review aims to summarize and discuss the diverse causes of two major gastrointestinal dysfunction symptoms, diarrhea and constipation, in cancer patients. We also discuss short- and long-term clinical, economic, and humanistic consequences, including the impact on cancer treatment regimens and patient quality of life, highlighting the limitations of the literature.

RECENT FINDINGS

Diarrhea and constipation as a result of cancer and its treatment can risk the success of anti-cancer therapies by requiring treatment delay or withdrawal, and imposes a substantial humanistic burden in patients with cancer. Despite its importance and frequency, gastrointestinal side effects may be overlooked due to the focus on cancer treatment, and the impact on patients may be underestimated. Additionally, the burden reported may not fully reflect current cancer management, particularly the true impact of economic consequences. A full understanding of the burden of diarrhea and constipation in patients with cancer is required, including broad evaluation of clinical considerations, the patient experience, and an updated assessment of economic burden. This would improve caregivers' appreciation of the impact of gastrointestinal dysfunction and aid the prioritization of future research efforts.

Outcomes from colonoscopy following referral from New Zealand general practice: a retrospective analysis

Background

New Zealand has high rates of colorectal cancer (CRC) but poor outcomes. Most patients with CRC are diagnosed following referral from general practice, where a general practitioner (GP) assesses symptoms according to national guidelines. All referred patients are then re-prioritised by the hospital system. The first objective of this study was to identify what proportion of patients referred by general practice to surgical/gastroenterology at Waikato District Health Board (DHB) had a colonoscopy. The second objective was to determine what proportion of these referrals have an underlying CRC and the factors associated with the likelihood of this diagnosis.

Methods

This study is a retrospective analysis of e-referral data for patients aged 30–70+ who were referred from 75 general practices to general surgery, gastroenterology or direct to colonoscopy at Waikato DHB, 01 January 2015–31 December 2017. Primary and secondary outcome measures included the proportion and characteristics of patients who were having colonoscopy, and of those, who were diagnosed with CRC. Data were analysed using chi square and logistic regression.

Results

6718/20648 (32.5%) patients had a colonoscopy and 372 (5.5%) of these were diagnosed with CRC. The probability of having CRC following a colonoscopy increased with age (p value < 0.001). Females (p value < 0.001), non-Māori (p value < 0.001), and patients with a high suspicion of cancer (HSCan) label originating from their GP were more likely to have a colonoscopy, while the odds ratio of Māori having a colonoscopy was 0.66 (95% CI 0.60–0.73). The odds ratio of a CRC diagnosis following colonoscopy was 1.67 (95% CI 1.35–2.07) for men compared to women, and 2.34 (95% CI 1.70–3.22) for those with a GP HSCan label. Of the 585 patients referred with a GP HSCan, 423 (72.3%) were reprioritised by the hospital and 55 patients had their diagnosis unnecessarily delayed.

Conclusions

If a GP refers a patient with an HSCan, and the patient receives a colonoscopy, then the likelihood of having CRC is almost 15.0%. This would suggest that these patients should be routinely prioritised without further triage by the hospital. Further research is needed to understand why Māori are less likely to receive a colonoscopy following referral from general practice.

Cancer diagnostic tools to aid decision-making in primary care: mixed-methods systematic reviews and cost-effectiveness analysis

BACKGROUND

Tools based on diagnostic prediction models are available to help general practitioners diagnose cancer. It is unclear whether or not tools expedite diagnosis or affect patient quality of life and/or survival.

OBJECTIVES

The objectives were to evaluate the evidence on the validation, clinical effectiveness, cost-effectiveness, and availability and use of cancer diagnostic tools in primary care.

METHODS

Two systematic reviews were conducted to examine the clinical effectiveness (review 1) and the development, validation and accuracy (review 2) of diagnostic prediction models for aiding general practitioners in cancer diagnosis. Bibliographic searches were conducted on MEDLINE, MEDLINE In-Process, EMBASE, Cochrane Library and Web of Science) in May 2017, with updated searches conducted in November 2018. A decision-analytic model explored the tools' clinical effectiveness and cost-effectiveness in colorectal cancer. The model compared patient outcomes and costs between strategies that included the use of the tools and those that did not, using the NHS perspective. We surveyed 4600 general practitioners in randomly selected UK practices to determine the proportions of general practices and general practitioners with access to, and using, cancer decision support tools. Association between access to these tools and practice-level cancer diagnostic indicators was explored.

RESULTS

Systematic review 1 - five studies, of different design and quality, reporting on three diagnostic tools, were included. We found no evidence that using the tools was associated with better outcomes. Systematic review 2 - 43 studies were included, reporting on prediction models, in various stages of development, for 14 cancer sites (including multiple cancers). Most studies relate to QCancer^® (ClinRisk Ltd, Leeds, UK) and risk assessment tools.

DECISION MODEL

In the absence of studies reporting their clinical outcomes, QCancer and risk assessment tools were evaluated against faecal immunochemical testing. A linked data approach was used, which translates diagnostic accuracy into time to diagnosis and treatment, and stage at diagnosis. Given the current lack of evidence, the model showed that the cost-effectiveness of diagnostic tools in colorectal cancer relies on demonstrating patient survival benefits. Sensitivity of faecal immunochemical testing and specificity of QCancer and risk assessment tools in a low-risk population were the key uncertain parameters.

SURVEY

Practitioner- and practice-level response rates were 10.3% (476/4600) and 23.3% (227/975), respectively. Cancer decision support tools were available in 83 out of 227 practices (36.6%, 95% confidence interval 30.3% to 43.1%), and were likely to be used in 38 out of 227 practices (16.7%, 95% confidence interval 12.1% to 22.2%). The mean 2-week-wait referral rate did not differ between practices that do and practices that do not have access to QCancer or risk assessment tools (mean difference of 1.8 referrals per 100,000 referrals, 95% confidence interval -6.7 to 10.3 referrals per 100,000 referrals).

LIMITATIONS

There is little good-quality evidence on the clinical effectiveness and cost-effectiveness of diagnostic tools. Many diagnostic prediction models are limited by a lack of external validation. There are limited data on current UK practice and clinical outcomes of diagnostic strategies, and there is no evidence on the quality-of-life outcomes of diagnostic results. The survey was limited by low response rates.

CONCLUSION

The evidence base on the tools is limited. Research on how general practitioners interact with the tools may help to identify barriers to implementation and uptake, and the potential for clinical effectiveness.

FUTURE WORK

Continued model validation is recommended, especially for risk assessment tools. Assessment of the tools' impact on time to diagnosis and treatment, stage at diagnosis, and health outcomes is also recommended, as is further work to understand how tools are used in general practitioner consultations.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017068373 and CRD42017068375.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology programme and will be published in full in Health Technology Assessment; Vol. 24, No. 66. See the NIHR Journals Library website for further project information.

Predictive values for different cancers and inflammatory bowel disease of 6 common abdominal symptoms among more than 1.9 million primary care patients in the UK: A cohort study

BACKGROUND

The diagnostic assessment of abdominal symptoms in primary care presents a challenge. Evidence is needed about the positive predictive values (PPVs) of abdominal symptoms for different cancers and inflammatory bowel disease (IBD).

METHODS AND FINDINGS

Using data from The Health Improvement Network (THIN) in the United Kingdom (2000-2017), we estimated the PPVs for diagnosis of (i) cancer (overall and for different cancer sites); (ii) IBD; and (iii) either cancer or IBD in the year post-consultation with each of 6 abdominal symptoms: dysphagia (n = 86,193 patients), abdominal bloating/distension (n = 100,856), change in bowel habit (n = 106,715), rectal bleeding (n = 235,094), dyspepsia (n = 517,326), and abdominal pain (n = 890,490). The median age ranged from 54 (abdominal pain) to 63 years (dysphagia and change in bowel habit); the ratio of women/men ranged from 50%:50% (rectal bleeding) to 73%:27% (abdominal bloating/distension). Across all studied symptoms, the risk of diagnosis of cancer and the risk of diagnosis of IBD were of similar magnitude, particularly in women, and younger men. Estimated PPVs were greatest for change in bowel habit in men (4.64% cancer and 2.82% IBD) and for rectal bleeding in women (2.39% cancer and 2.57% IBD) and lowest for dyspepsia (for cancer: 1.41% men and 1.03% women; for IBD: 0.89% men and 1.00% women). Considering PPVs for specific cancers, change in bowel habit and rectal bleeding had the highest PPVs for colon and rectal cancer; dysphagia for esophageal cancer; and abdominal bloating/distension (in women) for ovarian cancer. The highest PPVs of abdominal pain (either sex) and abdominal bloating/distension (men only) were for non-abdominal cancer sites. For the composite outcome of diagnosis of either cancer or IBD, PPVs of rectal bleeding exceeded the National Institute of Health and Care Excellence (NICE)-recommended specialist referral threshold of 3% in all age-sex strata, as did PPVs of abdominal pain, change in bowel habit, and dyspepsia, in those aged 60 years and over. Study limitations include reliance on accuracy and completeness of coding of symptoms and disease outcomes.

CONCLUSIONS

Based on evidence from more than 1.9 million patients presenting in primary care, the findings provide estimated PPVs that could be used to guide specialist referral decisions, considering the PPVs of common abdominal symptoms for cancer alongside that for IBD and their composite outcome (cancer or IBD), taking into account the variable PPVs of different abdominal symptoms for different cancers sites. Jointly assessing the risk of cancer or IBD can better support decision-making and prompt diagnosis of both conditions, optimising specialist referrals or investigations, particularly in women.

Prioritisation of lower gastrointestinal endoscopy during the COVID-19 pandemic: outcomes of a novel triage pathway

OBJECTIVE

The 2-week-wait (2ww) referral pathway is used in England to fast-track patients with suspected colorectal cancer (CRC). A two-stage triage pathway was used to prioritise lower gastrointestinal (LGI) endoscopy for suspected CRC during the COVID-19 pandemic.

METHOD

All patients referred for an LGI endoscopy via a 2ww referral pathway between March 2020 and July 2020 were assessed. The first stage triaged patients to high, standard or low risk of CRC based on symptoms and faecal immunochemical test (FIT), and offered CT scans to those at high risk. The second stage, endoscopy prioritisation (EP), incorporated the CT results, FIT and symptoms to triage into four groups, EP1-EP4; with EP1 being the most urgent and EP4 the least. The primary outcome measure was CRC detection.

RESULTS

514 patients were included. The risk of CRC was triaged as high in 190/514 patients (37%), standard in 274/514 patients (53%) and low in 50/514 (10%) patients. 422/514 patients (82%) underwent endoscopy with triage to EP1 in 52/422 (12%), EP2 in 105/422 (25%), EP3 in 210/422 (50%) and EP4 in 55/422 (13%). CRC was detected in 23 patients (5.4%). CRC was significantly more frequent in the EP1 group (23.1%, relative risk (RR)=16.2) and EP2 group (6.7%, RR=4.7) compared with EP3 group (1.4%). All CRC lesions were identified by CT imaging when performed prior to LGI endoscopy.

CONCLUSION

This triage pathway designated 83% of patients with CRC to either EP1 or EP2. During a period of limited endoscopy provision, this pathway effectively prioritises endoscopy for those at greatest risk of CRC.

A population-based study on time trends of hemoglobin in primary care comparing prediagnostic colorectal cancer patients vs age- and sex-matched controls

BACKGROUND

Some 40% of colorectal cancer (CRC) patients present with anemia. Temporal trends of gradually decreasing Hb are suggested as a supplementary diagnostic tool for CRC. We set out to explore this concept in a strictly defined population.

METHODS

A laboratory database identified patients ≥40 years that had ≥1 Hb test reported from primary care, Örebro county in 2000-17. Linkage to the Swedish Colorectal Cancer Registry identified patients diagnosed with CRC. Other primary care patients served as controls (1:10), matched by age and sex. Prediagnostic Hb in cases and controls were compared and temporal trajectories of Hb modelled using a nonlinear three-parameter logistic function.

RESULTS

1,534 CRC patients and 15,333 controls were identified. The average number of reported Hb tests in primary care per year increased successively, and diagnostic delay from detection of anemia to diagnosis of CRC decreased; in 2015-17 it was median 4 (IQR 2-6) months. No association was found between last Hb and stage of right-/left-sided colon, or rectal cancer.A statistically significantly lower Hb in CRC patients was discernable 609 days (20 months) prior to diagnosis for men and 905 days (30 months) for women, both in the range of normal Hb. The frequency of Hb testing in the general population via primary care was surprisingly low, and was ≥50% annually only in octogenarians.

CONCLUSION

The findings indicate a potential for Hb trends to inform the diagnostic process of CRC but whether it will translate into any clinical advantage is yet uncertain.

Diagnosing colorectal cancer in primary care: cohort study in Sweden of qualitative faecal immunochemical tests, haemoglobin levels, and platelet counts

BACKGROUND

Colorectal cancer (CRC) diagnostics are challenging in primary care and reliable diagnostic aids are desired. Qualitative faecal immunochemical tests (FITs) have been used for suspected CRC in Sweden since the mid-2000s, but evidence regarding their effectiveness is scarce. Anaemia and thrombocytosis are both associated with CRC.

AIM

To evaluate the usefulness of qualitative FITs requested for symptomatic patients in primary care, alone and combined with findings of anaemia and thrombocytosis, in the diagnosis of CRC.

DESIGN AND SETTING

A population-based cohort study using electronic health records and data from the Swedish Cancer Register, covering five Swedish regions.

METHOD

Patients aged ≥18 years in the five regions who had provided FITs requested by primary care practitioners from 1 January 2015 to 31 December 2015 were identified. FIT and blood-count data were registered and all CRC diagnoses made within 2 years were retrieved. Diagnostic measurements were calculated.

RESULTS

In total, 15 789 patients provided FITs (four different brands); of these patients, 304 were later diagnosed with CRC. Haemoglobin levels were available for 13 863 patients, and platelet counts for 10 973 patients. Calculated for the different FIT brands only, the sensitivities for CRC were 81.6%-100%; specificities 65.7%-79.5%; positive predictive values 4.7%-8.1%; and negative predictive values 99.5%-100%. Calculated for the finding of either a positive FIT or anaemia, the sensitivities increased to 88.9-100%. Adding thrombocytosis did not further increase the diagnostic performance.

CONCLUSION

Qualitative FITs requested in primary care seem to be useful as rule-in tests for referral when CRC is suspected. A negative FIT and no anaemia indicate a low risk of CRC.

Screening to identify postoperative pain and cross-sectional associations between factors identified in this process with pain and function, three months after total knee replacement

Objective

To describe the screening and recruitment process of a randomized trial and evaluate associations with knee pain and function 3 months after total knee replacement (TKR).

Methods

In order to screen for a multicenter trial, a total of 5,036 patients were sent the Oxford Knee Score (OKS) questionnaire 10 weeks post‐TKR. Patients who reported pain in their replaced knee (score of ≤14 on the OKS pain component) completed a second OKS questionnaire 12 weeks post‐TKR. Those patients who were still experiencing pain 12 weeks post‐TKR completed a detailed questionnaire 13 weeks post‐TKR. These data were used to characterize pain in a cross‐sectional analysis. Multivariable regression was performed in order to identify factors associated with pain and function at 13 weeks post‐TKR.

Results

We received OKS questionnaires from 3,058 of 5,063 TKR patients (60%), and 907 of the 3,058 (30%) reported pain in their replaced knee 10 weeks post‐TKR. By 12 weeks, 179 of 553 patients (32%) reported improved pain (score of >14 on the OKS pain component). At 13 weeks, 192 of 363 patients (53%) who completed a detailed questionnaire reported neuropathic pain, 94 of 362 (26%) reported depression symptoms, and 95 of 363 (26%) anxiety symptoms. More severe pain at 13 weeks postoperatively was associated with poorer general health, poorer physical health, more pain worry, and lower satisfaction with surgery outcome. More severe functional limitation was associated with higher levels of depression, more pain worry, lower satisfaction with surgery outcome, and higher pain acceptance.

Conclusion

Screening after TKR identified individuals with pain. We identified several potential targets (physical and mental health outcomes, acceptance of pain, and quality of life) for tailored intervention to improve outcomes for patients. Future trials of multidisciplinary interventions warranted.

Development, validation and effectiveness of diagnostic prediction tools for colorectal cancer in primary care: a systematic review

BACKGROUND

Tools based on diagnostic prediction models are available to help general practitioners (GP) diagnose colorectal cancer. It is unclear how well they perform and whether they lead to increased or quicker diagnoses and ultimately impact on patient quality of life and/or survival. The aim of this systematic review is to evaluate the development, validation, effectiveness, and cost-effectiveness, of cancer diagnostic tools for colorectal cancer in primary care.

METHODS

Electronic databases including Medline and Web of Science were searched in May 2017 (updated October 2019). Two reviewers independently screened titles, abstracts and full-texts. Studies were included if they reported the development, validation or accuracy of a prediction model, or assessed the effectiveness or cost-effectiveness of diagnostic tools based on prediction models to aid GP decision-making for symptomatic patients presenting with features potentially indicative of colorectal cancer. Data extraction and risk of bias were completed by one reviewer and checked by a second. A narrative synthesis was conducted.

RESULTS

Eleven thousand one hundred thirteen records were screened and 23 studies met the inclusion criteria. Twenty-studies reported on the development, validation and/or accuracy of 13 prediction models: eight for colorectal cancer, five for cancer areas/types that include colorectal cancer. The Qcancer models were generally the best performing. Three impact studies met the inclusion criteria. Two (an RCT and a pre-post study) assessed tools based on the RAT prediction model. The third study looked at the impact of GP practices having access to RAT or Qcancer. Although the pre-post study reported a positive impact of the tools on outcomes, the results of the RCT and cross-sectional survey found no evidence that use of, or access to, the tools was associated with better outcomes. No study evaluated cost effectiveness.

CONCLUSIONS

Many prediction models have been developed but none have been fully validated. Evidence demonstrating improved patient outcome of introducing the tools is the main deficiency and is essential given the imperfect classification achieved by all tools. This need is emphasised by the equivocal results of the small number of impact studies done so far.

Understanding the role of GPs' gut feelings in diagnosing cancer in primary care: a systematic review and meta-analysis of existing evidence

BACKGROUND

Growing evidence for the role of GPs' gut feelings in cancer diagnosis raises questions about their origin and role in clinical practice.

AIM

To explore the origins of GPs' gut feelings for cancer, their use, and their diagnostic utility.

DESIGN AND SETTING

Systematic review and meta-analysis of international research on GPs' gut feelings in primary care.

METHOD

Six databases were searched from inception to July 2019, and internet searches were conducted. A segregated method was used to analyse, then combine, quantitative and qualitative findings.

RESULTS

Twelve articles and four online resources were included that described varied conceptualisations of gut feelings. Gut feelings were often initially associated with patients being unwell, rather than with a suspicion of cancer, and were commonly experienced in response to symptoms and non-verbal cues. The pooled odds of a cancer diagnosis were four times higher when gut feelings were recorded (OR 4.24, 95% confidence interval = 2.26 to 7.94); they became more predictive of cancer as clinical experience and familiarity with the patient increased. Despite being included in some clinical guidelines, GPs had varying experiences of acting on gut feelings as some specialists questioned their diagnostic value. Consequently, some GPs ignored or omitted gut feelings from referral letters, or chose investigations that did not require specialist approval.

CONCLUSION

GPs' gut feelings for cancer were conceptualised as a rapid summing up of multiple verbal and non-verbal patient cues in the context of the GPs' clinical knowledge and experience. Triggers of gut feelings not included in referral guidance deserve further investigation as predictors of cancer. Non-verbal cues that trigger gut feelings appear to be reliant on continuity of care and clinical experience; they tend to remain poorly recorded and are, therefore, inaccessible to researchers.

The Full Blood Count Blood Test for Colorectal Cancer Detection: A Systematic Review, Meta-Analysis, and Critical Appraisal

INTRODUCTION

A full blood count (FBC) blood test includes 20 components. We systematically reviewed studies that assessed the association of the FBC and diagnosis of colorectal cancer to identify components as risk factors. We reviewed FBC-based prediction models for colorectal cancer risk.

METHODS

MEDLINE, EMBASE, CINAHL, and Web of Science were searched until 3 September 2019. We meta-analysed the mean difference in FBC components between those with and without a diagnosis and critically appraised the development and validation of FBC-based prediction models.

RESULTS

We included 53 eligible articles. Three of four meta-analysed components showed an association with diagnosis. In the remaining 16 with insufficient data for meta-analysis, three were associated with colorectal cancer. Thirteen FBC-based models were developed. Model performance was commonly assessed using the c-statistic (range 0.72-0.91) and calibration plots. Some models appeared to work well for early detection but good performance may be driven by early events.

CONCLUSION

Red blood cells, haemoglobin, mean corpuscular volume, red blood cell distribution width, white blood cell count, and platelets are associated with diagnosis and could be used for referral. Existing FBC-based prediction models might not perform as well as expected and need further critical testing.

Measuring the impact of national guidelines: What methods can be used to uncover time-varying effects for healthcare evaluations?

We examine the suitability of three methods using patient-level data to evaluate the time-varying impacts of national healthcare guidelines. Such guidelines often codify progressive change and are implemented gradually; for example, National Institute for Health and Care Excellence (NICE) suspected-cancer referral guidelines. These were revised on June 23, 2015, to include more cancer symptoms and test results ("features"), partly reflecting changing practice. We explore the time-varying impact of guideline revision on time to colorectal cancer diagnosis, which is linked to improved outcomes in decision-analytic models. We included 11,842 patients diagnosed in 01/01/2006-31/12/2017 in the Clinical Practice Research Datalink with England cancer registry data linkage. Patients were classified by whether their first pre-diagnostic cancer feature was in the original guidelines (NICE-2005) or was added during the revision (NICE-2015-only). Outcome was diagnostic interval: time from first cancer feature to diagnosis. All analyses adjusted for age and sex. Two difference-in-differences analyses used either a Pre (01/08/2012-31/12/2014, n = 2243) and Post (01/08/2015-31/12/2017, n = 1017) design, or event-study cohorts (2006-2017 vs 2015) to estimate change in diagnostic interval attributable to official implementation of the revised guidelines. A semiparametric varying-coefficient model analysed the difference in diagnostic interval between the NICE groups over time. After model estimation, primary and broader treatment effects of guideline content and implementation were measured. The event-study difference-in-differences and the semiparametric varying-coefficient methods showed that shorter diagnostic intervals were attributable to official implementation of the revised guidelines. This impact was only detectable by pre-to-post difference-in-differences when the pre/post periods were selected according to the estimation results from the varying-coefficient model. Formal tests of the parametric models, which are special cases of the semiparametric model, suggest that they are misspecified. We conclude that the semiparametric method is well suited to explore the time-varying impacts of guidelines codifying progressive change.

Patient-reported and doctor-reported symptoms when faecal immunochemical tests are requested in primary care in the diagnosis of colorectal cancer and inflammatory bowel disease: a prospective study

BACKGROUND

Rectal bleeding and a change in bowel habits are considered to be alarm symptoms for colorectal cancer and they are also common symptoms for inflammatory bowel disease. However, most patients with these symptoms do not have any of these diseases. Faecal immunochemical tests (FITs) for haemoglobin are used as triage tests in Sweden and other countries but little is known about the symptoms patients have when FITs are requested.

OBJECTIVE

Firstly, to determine patients' symptoms when FITs are used as triage tests in primary care and whether doctors record the symptoms that patients report, and secondly to evaluate the association between symptoms, FIT results and possible prediction of colorectal cancer or inflammatory bowel disease.

METHODS AND MATERIALS

This prospective study included 364 consecutive patients for whom primary care doctors requested a FIT. Questionnaires including gastrointestinal symptoms were completed by patients and doctors.

RESULTS

Concordance between symptoms reported from patients and doctors was low. Rectal bleeding was recorded by 43.5% of patients versus 25.6% of doctors, FITs were negative in 58.3 and 52.7% of these cases respectively. The positive predictive value (PPV) of rectal bleeding recorded by patients for colorectal cancer or inflammatory bowel disease was 9.9% (95% confidence interval [CI] 5.2-14.7); for rectal bleeding combined with a FIT the PPV was 22.6% (95% CI 12.2-33.0) and the negative predictive value (NPV) was 98.9% (95% CI 96.7-100). For patient-recorded change in bowel habits the PPV was 6.1% (95% CI 2.4-9.8); for change in bowel habits combined with a FIT the PPV was 18.2% (95% CI 9.1-30.9) and the NPV 100% (95% CI 90.3-100).

CONCLUSIONS

Doctors should be aware that, during consultations, they do not record all symptoms experienced by patients. FITs requested in primary care, when found positive, may potentially be of help in prioritising referrals, also when patients present with rectal bleeding or change in bowel habits.

The use of electronic healthcare records for colorectal cancer screening referral decisions and risk prediction model development

BACKGROUND

The database used for the NHS Bowel Cancer Screening Programme (BCSP) derives participant information from primary care records. Combining predictors with FOBTs has shown to improve referral decisions and accuracy. The richer data available from GP databases could be used to complement screening referral decisions by identifying those at greatest risk of colorectal cancer. We determined the availability of data for key predictors and whether this information could be used to inform more accurate screening referral decisions.

METHODS

An English BCSP cohort was derived using the electronic notifications received from the BCSP database to GP records. The cohort covered a period between 13th May 2009 to 17th January 2017. Completeness of variables and univariable associations were assessed. Risk prediction models were developed using Cox regression and multivariable fractional polynomials with backwards elimination. Optimism adjusted performance metrics were reported. The sensitivity and specificity of a combined approach using the negative FOBT model plus FOBT positive patients was determined using a probability equivalent to a 3% PPV NICE guidelines level.

RESULTS

292,059 participants aged 60-74 were derived for the BCSP screening cohort. A model including the screening test result had a C-statistic of 0.860, c-slope of 0.997, and R² of 0.597. A model developed for negative screening results only had a C-statistic of 0.597, c-slope of 0.940, and R² of 0.062. Risk predictors included in the models included; age, sex, alcohol consumption, IBS diagnosis, family history of gastrointestinal cancer, smoking status, previous negatives and whether a GP had ordered a blood test. For the combined screening approach, sensitivity increased slightly from 53.90% (FOBT only) to 58.82% but at the expense of an increased referral rate.

CONCLUSIONS

This research has identified several potential predictors for CRC in a BCSP population. A risk prediction model developed for BCSP FOBT negative patients was not clinically useful due to a low sensitivity and increased referral rate. The predictors identified in this study should be investigated in a refined algorithm combining the quantitative FIT result. Combining data from multiple sources enables fuller patient profiles using the primary care and screening database interface.

Diagnostic accuracy of a quantitative faecal immunochemical test vs. symptoms suspected for colorectal cancer in patients referred for colonoscopy

Objective: Determine diagnostic accuracy of a quantitative faecal immunochemical haemoglobin test (QuikRead go^® FIT, Orion Diagnostica Oy) in symptomatic patients referred for colonoscopy, at various cut-offs and for one or two tests.Methods: Patients referred to four endoscopy units in mid-Sweden between 2013 and 2017 provided information on lower abdominal symptoms and faecal samples from two separate days prior to colonoscopy.Results: In all, 5.4% (13/242) patients had colorectal cancer (CRC). For one FIT at cut-off 10 µg Hb/g faeces, sensitivity for CRC was 92% (95% CI 78-100%) and specificity 77% (95% CI 72-83%); equal to 74%; 95% CI 68-80 (178/242) colonoscopies potentially avoidable and one CRC missed. Based on the maximal outcome of two FITs, sensitivity was 100%, specificity 71% (66-77%) and 68%; 95% CI 62-74 (160/237) colonoscopies potentially avoidable. Among 17% (42/242) patients with one FIT of >200 µg Hb/g faeces, 85% (11/13) had CRC. Positive predictive values of FIT varied 16.9-26.2% depending on cut-off and one or two FITs, whereas NPVs were 99% and above in all scenarios.In 60 patients reporting rectal bleeding, one FIT at cut-off 10 µg Hb/g discriminated well between CRC and other conditions (p = .001). In regression models, FIT was more important than age, sex and all symptoms.Conclusion: One or two FITs in symptomatic patients referred for colonoscopy imply powerful risk stratification abilities for CRC, even among patients reporting rectal bleeding. Larger studies in various settings will clarify how to make the best use of this opportunity. Trial registration: Clinicaltrails.gov NCT02491593.

Prevalence of gastrointestinal malignancy in iron deficiency without anaemia: A systematic review and meta-analysis

BACKGROUND

Iron deficiency anaemia is associated with gastrointestinal (GI) malignancy and is an indication for GI investigations. However, the relevance of iron deficiency without anaemia (IDWA) and the underlying risks of GI malignancy are uncertain. Therefore, the aim of this study was to estimate the prevalence of GI malignancy in patients with IDWA overall and in clinically relevant subgroups.

METHODS

We searched MEDLINE and EMBASE for studies that reported on the prevalence or risk of GI malignancy in patients with confirmed IDWA. We performed a random effects meta-analysis of proportions and assessed statistical heterogeneity using the I² statistic.

RESULTS

A total of 1923 citations were screened and 5 studies (4 retrospective cohorts, 1 prospective cohort) comprising 3329 participants with IDWA were included in the meta-analysis. Overall pooled random-effects estimates for prevalence of GI malignancy in those with IDWA were low (0.38%, 95% CI 0.00%-1.84%, I2 = 87.7%). Older patients (2.58%, 95% CI 0.00%-8.77%); non-screening populations (2.45%, 95% CI 0.16%-6.39%) and men and post-menopausal women (0.90%, 95% CI 0.11%-3.23%) with IDWA were at increased risk of GI malignancy compared to younger patients (0.00%, 95% CI 0.00%-0.21%); screened populations (0.24%, 95% CI 0.00%-1.10%) and pre-menopausal women (0.00%, 95% CI 0.00%-1.05%).

CONCLUSION

Overall, IDWA is associated with a low risk of GI malignancy. Older patients and non-screening populations are at elevated risk and require GI investigations. Those not in these subgroups have a lower risk of GI malignancy and may wish to be monitored following discussion of the risk and potential benefits of GI investigations.

Determinants and extent of weight recording in UK primary care: an analysis of 5 million adults' electronic health records from 2000 to 2017

BACKGROUND

Excess weight and unexpected weight loss are associated with multiple disease states and increased morbidity and mortality, but weight measurement is not routine in many primary care settings. The aim of this study was to characterise who has had their weight recorded in UK primary care, how frequently, by whom and in relation to which clinical events, symptoms and diagnoses.

METHODS

A longitudinal analysis of UK primary care electronic health records (EHR) data from 2000 to 2017. Descriptive statistics were used to summarise weight recording in terms of patient sociodemographic characteristics, health professional encounters, clinical events, symptoms and diagnoses. Negative binomial regression was used to model the likelihood of having a weight record each year, and Cox regression to the likelihood of repeated weight recording.

RESULTS

A total of 14,049,871 weight records were identified in the EHR of 4,918,746 patients during the study period, representing 26,998,591 person-years of observation. Around a third of patients had a weight record each year. Forty-nine percent of weight records were repeated within a year with an average time to a repeat weight record of 1.92 years. Weight records were most often taken by nursing staff (38-42%) and GPs (37-39%) as part of a routine clinical care, such as chronic disease reviews (16%), medication reviews (6-8%) and health checks (6-7%), or were associated with consultations for contraception (5-8%), respiratory disease (5%) and obesity (1%). Patient characteristics independently associated with an increased likelihood of weight recording were as follows: female sex, younger and older adults, non-drinkers, ex-smokers, low or high BMI, being more deprived, diagnosed with a greater number of comorbidities and consulting more frequently. The effect of policy-level incentives to record weight did not appear to be sustained after they were removed.

CONCLUSION

Weight recording is not a routine activity in UK primary care. It is recorded for around a third of patients each year and is repeated on average every 2 years for these patients. It is more common in females with higher BMI and in those with comorbidity. Incentive payments and their removal appear to be associated with increases and decreases in weight recording.

The diagnostic value of a change in bowel habit for colorectal cancer within different age groups

BACKGROUND

Change in bowel habit as a sole alarm symptom for colorectal cancer is disputed.

OBJECTIVE

We investigated the diagnostic value of change in bowel habit for colorectal cancer, particularly as a single symptom and within different age groups.

METHODS

This retrospective cohort study examined colorectal cancer fast track referrals and outcomes across four Swedish hospitals (April 2016-May 2017). Entry criteria constituted one or more of three alarm features: anaemia, visible rectal bleeding, or change in bowel habit for more than 4 weeks in patients over 40 years of age. Patients were grouped as having only change in bowel habit, change in bowel habit plus anaemia/bleeding or anaemia/bleeding only.

RESULTS

Of 628 patients, 22% were diagnosed with colorectal cancer. There were no cases of colorectal cancer in the only change in bowel habit group under 55 years, while this was 6% for 55-64 years, 8% for 65-74 years and 14% for 75 years and older. Among subjects under 55 years, 2% with anaemia/bleeding had colorectal cancer, this increased to 34% for 55 years and older (P < 0.0001). Change in bowel habit plus anaemia/bleeding gave a colorectal cancer prevalence of 16% in under 55 years and increased to 30% for 55 years and older (P = 0.07).

CONCLUSION

Change in bowel habit as the only alarm feature has a low diagnostic yield for colorectal cancer in patients under 55 years.

Contrasting effects of comorbidities on emergency colon cancer diagnosis: a longitudinal data-linkage study in England

BACKGROUND

One in three colon cancers are diagnosed as an emergency, which is associated with worse cancer outcomes. Chronic conditions (comorbidities) affect large proportions of adults and they might influence the risk of emergency presentations (EP).

METHODS

We aimed to evaluate the effect of specific pre-existing comorbidities on the risk of colon cancer being diagnosed following an EP rather than through non-emergency routes. The cohort study included 5745 colon cancer patients diagnosed in England 2005-2010, with individually-linked cancer registry, primary and secondary care data. In addition to multivariable analyses we also used potential-outcomes methods.

RESULTS

Colon cancer patients with comorbidities consulted their GP more frequently with cancer symptoms during the pre-diagnostic year, compared with non-comorbid cancer patients. EP occurred more frequently in patients with 'serious' or complex comorbidities (diabetes, cardiac and respiratory diseases) diagnosed/treated in hospital during the years pre-cancer diagnosis (43% EP in comorbid versus 27% in non-comorbid individuals; multivariable analysis Odds Ratio (OR), controlling for socio-demographic factors and symptoms: men OR = 2.40; 95% CI 2.0-2.9 and women OR = 1.98; 95% CI 1.6-2.4. Among women younger than 60, gynaecological (OR = 3.41; 95% CI 1.2-9.9) or recent onset gastro-intestinal conditions (OR = 2.84; 95% CI 1.1-7.7) increased the risk of EP. In contrast, primary care visits for hypertension monitoring decreased EPs for both genders.

CONCLUSIONS

Patients with comorbidities have a greater risk of being diagnosed with cancer as an emergency, although they consult more frequently with cancer symptoms during the year pre-cancer diagnosis. This suggests that comorbidities may interfere with diagnostic reasoning or investigations due to 'competing demands' or because they provide 'alternative explanations'. In contrast, the management of chronic risk factors such as hypertension may offer opportunities for earlier diagnosis. Interventions are needed to support the diagnostic process in comorbid patients. Appropriate guidelines and diagnostic services to support the evaluation of new or changing symptoms in comorbid patients may be useful.

Opportunities for reducing emergency diagnoses of colon cancer in women and men: A data-linkage study on pre-diagnostic symptomatic presentations and benign diagnoses

OBJECTIVES

To identify opportunities for reducing emergency colon cancer diagnoses, we evaluated symptoms and benign diagnoses recorded before emergency presentations (EP).

METHODS

Cohort of 5,745 colon cancers diagnosed in England 2005-2010, with individually linked cancer registry and primary care data for the 5-year pre-diagnostic period.

RESULTS

Colon cancer was diagnosed following EP in 34% of women and 30% of men. Among emergency presenters, 20% of women and 15% of men (p = 0.002) had alarm symptoms (anaemia/rectal bleeding/change in bowel habit) 2-12 months pre-diagnosis. Women with abdominal symptoms (change in bowel habit/constipation/diarrhoea) received a benign diagnosis (irritable bowel syndrome (IBS)/diverticular disease) more frequently than men in the year before EP: 12% vs. 6% among women and men (p = 0.002). EP was more likely in women (OR = 1.20; 95% CI 1.1-1.4), independently of socio-demographic factors and symptoms. Benign diagnoses in the pre-diagnostic year (OR = 2.01; 95% CI 1.2-3.3) and anaemia 2-5 years pre-diagnosis (OR = 1.91; 95% CI 1.2-3.0) increased the risk of EP in women but not men. The risk was particularly high for women aged 40-59 with a recent benign diagnosis vs. none (OR = 4.41; 95% CI 1.3-14.9).

CONCLUSIONS

Women have an increased risk of EP, in part due to less specific symptoms and their more frequent attribution to benign diagnoses. For women aged 40-59 years with new-onset IBS/diverticular disease innovative diagnostic strategies are needed, which might include use of quantitative faecal haemoglobin testing (FIT) or other colorectal cancer investigations. One-fifth of women had alarm symptoms before EP, offering opportunities for earlier diagnosis.

The internal validation of weight and weight change coding using weight measurement data within the UK primary care Electronic Health Record

PURPOSE

To use recorded weight values to internally validate weight status and weight change coding in the primary care Electronic Health Record (EHR).

PATIENTS AND METHODS

We included adult patients with weight-related Read codes recorded in the UK's Clinical Practice Research Datalink EHR between 2000 and 2017. Weight status codes were compared to weight values recorded on the same day and positive predictive values (PPVs) were calculated for commonly used codes. Weight change codes were validated using three methods: the percentage (%) difference in kilograms at the time of the code and 1) the previous weight measurement, 2) the weight predicted using linear regression, and 3) the historic mean weight. Weight change codes were validated if estimates were consistent across two out of three methods.

RESULTS

A total of 8,108,481 weight codes were recorded in 1,000,002 patients' EHR. Twice as many were recorded in females (n=5,208,593, 64%). The mean body mass index for "overweight" codes ranged from 31.9 kg/m2 to 46.9 kg/m2 and from 17.4 kg/m2 to 19.2 kg/m2 for "underweight" codes. PPVs for the most commonly used weight status codes ranged from 81.3% (80%-82.5%) to 99.3% (99.2%-99.4%). Across the estimation methods, and using only validated weight change codes, mean weight loss ranged from - 5.2% (SD 5.8%) to -7.9% (SD 7.3%) and mean weight gain from 4.2 % (SD 5.5%) to 7.9 % (SD 8.2%). The previous and predicted weight methods were most consistent.

CONCLUSION

We have developed an internationally applicable methodology to internally validate weight-related EHR coding by using available weight measurement data. We demonstrate the UK Read codes that can be confidently used to classify weight status and weight change in the absence of weight values. We provide the first evidence from primary care that a Read code for unexpected weight loss represents a mean loss of ≥ 5 % in a 6-month period, which was broadly consistent across age groups and gender.

A review of sex-related differences in colorectal cancer incidence, screening uptake, routes to diagnosis, cancer stage and survival in the UK

Background

Colorectal cancer (CRC) is an illness strongly influenced by sex and gender, with mortality rates in males significantly higher than females. There is still a dearth of understanding on where sex differences exist along the pathway from presentation to survival. The aim of this review is to identify where actions are needed to improve outcomes for both sexes, and to narrow the gap for CRC.

Methods

A cross-sectional review of national data was undertaken to identify sex differences in incidence, screening uptake, route to diagnosis, cancer stage at diagnosis and survival, and their influence in the sex differences in mortality.

Results

Overall incidence is higher in men, with an earlier age distribution, however, important sex differences exist in anatomical site. There were relatively small differences in screening uptake, route to diagnosis, cancer staging at diagnosis and survival. Screening uptake is higher in women under 69 years. Women are more likely to present as emergency cases, with more men diagnosed through screening and two-week-wait. No sex differences are seen in diagnosis for more advanced disease. Overall, age-standardised 5-year survival is similar between the sexes.

Conclusions

As there are minimal sex differences in the data from routes to diagnosis to survival, the higher mortality of colorectal cancer in men appears to be a result of exogenous and/or endogenous factors pre-diagnosis that lead to higher incidence rates. There are however, sex and gender differences that suggest more targeted interventions may facilitate prevention and earlier diagnosis in both men and women.

Diagnostic profile characteristics of cancer patients with frequent consultations in primary care before diagnosis: a case-control study

BACKGROUND

Many patients with common cancers are late diagnosed.

OBJECTIVES

Identify consultation profiles and clinical features in patients with the seven most common cancers, who had consulted a general practitioner (GP) frequently before their cancer diagnosis.

METHODS

A case-control study was conducted in Region Västra Götaland, Sweden. A total of 2570 patients, diagnosed in 2011 with prostate, breast, colorectal, lung, gynaecological and skin cancers including malignant melanoma, and 9424 controls were selected from the Swedish Cancer Register and a regional health care database. Diagnostic codes [International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10)] from primary care for patients with ≥4 GP consultations registered in the year before cancer diagnosis were collected. Likelihood ratios (LRs) were calculated for variables associated with the different cancers.

RESULTS

Fifty-six percent of the patients had consulted a GP four or more times in the year before cancer diagnosis. Alarm symptoms or signs represented 60% of the codes with the highest LR, but only 40% of the 10 most prevalent codes. Breast lump had the highest LR, 11.9 [95% confidence interval (CI) 8.0-17.8]; abnormalities of plasma proteins had an LR of 5.0 (95% CI 3.0-8.2) and abnormal serum enzyme levels had an LR of 4.6 (95% CI 3.6-5.9). Early clinical features associated with cancer had been registered already at the first two GP consultations.

CONCLUSION

One out of six clinical features associated with cancer were presented by cancer patients with four or more pre-referral consultations already at the two first consultations. These early clinical features that were focal and had benign characteristics might have been missed diagnostic opportunities.

Weight loss as a predictor of cancer in primary care: a systematic review and meta-analysis

BACKGROUND

Weight loss is a non-specific cancer symptom for which there are no clinical guidelines about investigation in primary care.

AIM

To summarise the available evidence on weight loss as a clinical feature of cancer in patients presenting to primary care.

DESIGN AND SETTING

A diagnostic test accuracy review and meta-analysis.

METHOD

Studies reporting 2 × 2 diagnostic accuracy data for weight loss (index test) in adults presenting to primary care and a subsequent diagnosis of cancer (reference standard) were included. QUADAS-2 was used to assess study quality. Sensitivity, specificity, positive likelihood ratios, and positive predictive values were calculated, and a bivariate meta-analysis performed.

RESULTS

A total of 25 studies were included, with 23 (92%) using primary care records. Of these, 20 (80%) defined weight loss as a physician's coding of the symptom; the remainder collected data directly. One defined unexplained weight loss using objective measurements. Positive associations between weight loss and cancer were found for 10 cancer sites: prostate, colorectal, lung, gastro-oesophageal, pancreatic, non-Hodgkin's lymphoma, ovarian, myeloma, renal tract, and biliary tree. Sensitivity ranged from 2% to 47%, and specificity from 92% to 99%, across cancer sites. The positive predictive value for cancer in male and female patients with weight loss for all age groups ≥60 years exceeded the 3% risk threshold that current UK guidance proposes for further investigation.

CONCLUSION

A primary care clinician's decision to code for weight loss is highly predictive of cancer. For such patients, urgent referral pathways are justified to investigate for cancer across multiple sites.

Primary care variability in patients at higher risk for colorectal cancer: evaluation of screening and preventive care practices

OBJECTIVE

Sub-optimal colorectal cancer (CRC) evaluations have been attributed to both physician and patient factors. The primary objective of this study was to evaluate physician practice variation in patients with a higher risk of CRC. We wanted to identify the physician characteristics and the types of patients that were associated with missed screening opportunities; we also explored whether screening for CRC served as a proxy for better preventive care practices.

METHODS

A total of 213 board-certified family and internal medicine physicians participated in the study, conducted between September and December 2016. We used Clinical Performance and Value (CPV^®) vignettes, simulated patients, to collect data on CRC screening. The CPV patients presented with a typical range of signs and symptoms of potential CRC. The care provided to the simulated patients was scored against explicit evidence-based criteria. The main outcome measure was rate a diagnostic CRC workup was ordered. This data quantified the clinical practice variability for CRC screening in high risk patients and other preventive and screening practices.

RESULTS

A total of 81% of participants ordered appropriate CRC workup in patients at risk for CRC, with a majority (71%) selecting diagnostic colonoscopy over FIT/FOBT. Only 6% of physicians ordering CRC workup, however, counseled patients on their higher risk for CRC. The most commonly recognized symptoms prompting testing were unexplained weight loss or inadequate screening history, while the least recognized symptoms of CRC risk were abdominal discomfort found on review of systems.

CONCLUSION

This study shows that primary care physician screening of CRC varies widely. Those physicians who successfully screened for CRC were more likely to complete other prevention and screening practices.

The contribution of a negative colorectal screening test result to symptom appraisal and help-seeking behaviour among patients subsequently diagnosed with an interval colorectal cancer

Background

Colorectal cancer (CRC) screening programmes using a guaiac faecal occult blood test (gFOBt) reduce CRC mortality. Interval cancers are diagnosed between screening rounds: reassurance from a negative gFOBt has the potential to influence the pathway to diagnosis of an interval colorectal cancer.

Methods

Twenty‐six semi‐structured face‐to‐face interviews were carried out in Scotland and England, with individuals diagnosed with an interval colorectal cancer following a negative gFOBt result.

Results

Participants reported they were reassured by a negative gFOBt, interpreting their result as an “all clear”. Therefore, most did not suspect cancer as a possible cause of symptoms and many did not recall their screening result during symptom appraisal. Among those who did consider cancer, and did think about their screening test result, reassurance from a negative gFOBt led some to “downplay” the seriousness of their symptoms with some interviewees explicitly stating that their negative test result contributed to a delayed decision to seek help.

Conclusion

Screening participants need to be informed of the limitations of screening and the ongoing risk of developing colorectal cancer even when in receipt of a negative result: the importance of minimizing delay in seeking medical advice for colorectal symptoms should be emphasized.

Symptom Signatures and Diagnostic Timeliness in Cancer Patients: A Review of Current Evidence

Early diagnosis is an important aspect of contemporary cancer prevention and control strategies, as the majority of patients are diagnosed following symptomatic presentation. The nature of presenting symptoms can critically influence the length of the diagnostic intervals from symptom onset to presentation (the patient interval), and from first presentation to specialist referral (the primary care interval). Understanding which symptoms are associated with longer diagnostic intervals to help the targeting of early diagnosis initiatives is an area of emerging research. In this Review, we consider the methodological challenges in studying the presenting symptoms and intervals to diagnosis of cancer patients, and summarize current evidence on presenting symptoms associated with a range of common and rarer cancer sites. We propose a taxonomy of cancer sites considering their symptom signature and the predictive value of common presenting symptoms. Finally, we consider evidence on associations between symptomatic presentations and intervals to diagnosis before discussing implications for the design, implementation, and evaluation of public health or health system interventions to achieve the earlier detection of cancer.

Weight loss as a predictor of cancer and serious disease in primary care: an ISAC-approved CPRD protocol for a retrospective cohort study using routinely collected primary care data from the UK

BACKGROUND

Unexpected weight loss is a symptom of serious disease in primary care, for example between 1 in 200 and 1 in 30 patients with unexpected weight loss go on to develop cancer. However, it remains unclear how and when general practitioners (GPs) should investigate unexpected weight loss. Without clarification, GPs may wait too long before referring (choosing to watch and wait and potentially missing a diagnosis) or not long enough (overburdening hospital services and exposing patients to the risks of investigation). The overall aim of this study is to provide the evidence necessary to allow GPs to more effectively manage patients with unexpected weight loss.

METHODS

A retrospective cohort analysis of UK Clinical Practice Research Datalink (CPRD) data to: (1) describe how often in UK primary care the symptom of reported weight loss is coded, when weight is measured, and how GPs respond to a patient attending with unexpected weight loss; (2) identify the predictive value of recorded weight loss for cancer and serious disease in primary care, using cumulative incidence plots to compare outcomes between subgroups and Cox regression to explore and adjust for covariates. Preliminary work in CPRD estimates that weight loss as a symptom is recorded for approximately 148,000 eligible patients > 18 years and is distributed evenly across decades of age, providing adequate statistical power and precision in relation to cancer overall and common cancers individually. Further stratification by cancer stage will be attempted but may not be possible as not all practices within CPRD are eligible for cancer registry linkage, and staging information is often incomplete. The feasibility of using multiple imputation to address missing covariate values will be explored.

DISCUSSION

This will be the largest reported retrospective cohort of primary care patients with weight measurements and unexpected weight loss codes used to understand the association between weight measurement, unexpected weight loss, and serious disease including cancer. Our findings will directly inform international guidelines for the management of unexpected weight loss in primary care populations.

Identifying clinical features in primary care electronic health record studies: methods for codelist development

OBJECTIVE

Analysis of routinely collected electronic health record (EHR) data from primary care is reliant on the creation of codelists to define clinical features of interest. To improve scientific rigour, transparency and replicability, we describe and demonstrate a standardised reproducible methodology for clinical codelist development.

DESIGN

We describe a three-stage process for developing clinical codelists. First, the clear definition a priori of the clinical feature of interest using reliable clinical resources. Second, development of a list of potential codes using statistical software to comprehensively search all available codes. Third, a modified Delphi process to reach consensus between primary care practitioners on the most relevant codes, including the generation of an 'uncertainty' variable to allow sensitivity analysis.

SETTING

These methods are illustrated by developing a codelist for shortness of breath in a primary care EHR sample, including modifiable syntax for commonly used statistical software.

PARTICIPANTS

The codelist was used to estimate the frequency of shortness of breath in a cohort of 28 216 patients aged over 18 years who received an incident diagnosis of lung cancer between 1 January 2000 and 30 November 2016 in the Clinical Practice Research Datalink (CPRD).

RESULTS

Of 78 candidate codes, 29 were excluded as inappropriate. Complete agreement was reached for 44 (90%) of the remaining codes, with partial disagreement over 5 (10%). 13 091 episodes of shortness of breath were identified in the cohort of 28 216 patients. Sensitivity analysis demonstrates that codes with the greatest uncertainty tend to be rarely used in clinical practice.

CONCLUSIONS

Although initially time consuming, using a rigorous and reproducible method for codelist generation 'future-proofs' findings and an auditable, modifiable syntax for codelist generation enables sharing and replication of EHR studies. Published codelists should be badged by quality and report the methods of codelist generation including: definitions and justifications associated with each codelist; the syntax or search method; the number of candidate codes identified; and the categorisation of codes after Delphi review.

Is whole-colon investigation by colonoscopy, computerised tomography colonography or barium enema necessary for all patients with colorectal cancer symptoms, and for which patients would flexible sigmoidoscopy suffice? A retrospective cohort study

BACKGROUND

For patients referred to hospital with suspected colorectal cancer (CRC), it is current standard clinical practice to conduct an examination of the whole colon and rectum. However, studies have shown that an examination of the distal colorectum using flexible sigmoidoscopy (FS) can be a safe and clinically effective investigation for some patients. These findings require validation in a multicentre study.

OBJECTIVES

To investigate the links between patient symptoms at presentation and CRC risk by subsite, and to provide evidence of whether or not FS is an effective alternative to whole-colon investigation (WCI) in patients whose symptoms do not suggest proximal or obstructive disease.

DESIGN

A multicentre retrospective study using data collected prospectively from two randomised controlled trials. Additional data were collected from trial diagnostic procedure reports and hospital records. CRC diagnoses within 3 years of referral were sourced from hospital records and national cancer registries via the Health and Social Care Information Centre.

SETTING

Participants were recruited to the two randomised controlled trials from 21 NHS hospitals in England between 2004 and 2007.

PARTICIPANTS

Men and women aged ≥ 55 years referred to secondary care for the investigation of symptoms suggestive of CRC.

MAIN OUTCOME MEASURE

Diagnostic yield of CRC at distal (to the splenic flexure) and proximal subsites by symptoms/clinical signs at presentation.

RESULTS

The data set for analysis comprised 7380 patients, of whom 59% were women (median age 69 years, interquartile range 62-76 years). Change in bowel habit (CIBH) was the most frequently presenting symptom (73%), followed by rectal bleeding (38%) and abdominal pain (29%); 26% of patients had anaemia. CRC was diagnosed in 551 patients (7.5%): 424 (77%) patients with distal CRC, 122 (22%) patients with cancer proximal to the descending colon and five patients with both proximal and distal CRC. Proximal cancer was diagnosed in 96 out of 2021 (4.8%) patients with anaemia and/or an abdominal mass. The yield of proximal cancer in patients without anaemia or an abdominal mass who presented with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom was low (0.5%). These low-risk groups for proximal cancer accounted for 41% (3032/7380) of the cohort; only three proximal cancers were diagnosed in 814 low-risk patients examined by FS (diagnostic yield 0.4%).

LIMITATIONS

A limitation to this study is that changes to practice since the trial ended, such as new referral guidelines and improvements in endoscopy quality, potentially weaken the generalisability of our findings.

CONCLUSIONS

Symptom profiles can be used to determine whether or not WCI is necessary. Most proximal cancers were diagnosed in patients who presented with anaemia and/or an abdominal mass. In patients without anaemia or an abdominal mass, proximal cancer diagnoses were rare in those with rectal bleeding with or without a CIBH or with a CIBH to looser and/or more frequent stools as a single symptom. FS alone should be a safe and clinically effective investigation in these patients. A cost-effectiveness analysis of symptom-based tailoring of diagnostic investigations for CRC is recommended.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95152621.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 66. See the NIHR Journals Library website for further project information.

Barriers to Colorectal Cancer Screening in Pakistan

Background The prevalence of colorectal cancer (CRC) is growing in Pakistan; however, there are no national screening programs or guidelines in place to curb its development. This study was conducted with the aim of ascertaining public awareness and attitudes regarding CRC and current screening practices. Furthermore, the study assessed perceived barriers which could impact future screening processes. Methods A cross-sectional, questionnaire-based study was conducted among urban dwellers of Karachi, Pakistan. We excluded any individuals belonging to the medical profession, those diagnosed previously with CRC or having any significant co-morbidity. The validated and pre-tested questionnaire was administered among the study participants to record demographic information, awareness of CRC risk factors, symptoms and screening tests. Attitudes towards screening and perceived barriers to screening were also assessed. Data were analyzed using Statistical Package for Social Sciences (SPSS version 20.0) (IBM Corp., Armonk, NY). A knowledge score, out of a total of 14 points was calculated to reflect a participant's overall knowledge regarding CRC risk factors and signs/symptoms. Results The prevalence of CRC screening in eligible individuals (50 years or older) was 2.6% in our study population. Positive attitudes towards CRC management and screening were observed, with 75.1% (n = 296) acknowledging the preventive role of screening tests. Despite this only 14.9% (n = 58) of study participants expressed a future desire to undergo screening. Major barriers to screening were reported to be "a lack of knowledge regarding the screening procedure", a "lack of screening facilities" and that the "screening procedure is too expensive". A majority (n = 285, 72.3%) of the participants expressed a greater willingness to undergo screening if their doctor recommended it. Conclusion A national CRC screening and awareness program should be launched to promote awareness and facilitate screening in risk groups. General practitioners are needed to play a key role in counseling patients and endorsing healthy screening practices.

Clinical utility of a blood-based protein assay to increase screening of elevated-risk patients for colorectal cancer in the primary care setting

PURPOSE

Colorectal cancer (CRC) screening is effective in finding early stage CRC and dramatically improves survival rates. Despite this, the number of eligible patients who do not obtain CRC screening is unacceptably high.

METHODS

We conducted a longitudinal, randomized controlled trial investigating the utility of a blood-based protein assay on the quality of care delivered by practicing PCPs in the United States. We used standardized simulated patients (CPVs), presenting with symptoms suggestive of a higher likelihood of CRC, to measure how frequently these PCPs ordered diagnostic colonoscopy. 190 PCPs cared for three patients at baseline and three patients post-intervention. The PCPs were randomized into one of two study arms: control and intervention. The intervention arm consisted of educational materials about the blood-based protein assay and positive test results. Each simulated patient in the intervention arm had a positive test result that was given to the doctor. The controls were given neither intervention materials nor blood-based protein assay results. Physician responses in both groups were scored against evidence-based criteria. Data were collected at baseline and post-intervention.

RESULTS

At baseline, we found that 71% of physicians ordered diagnostic colonoscopy. In round 2, 23% of physicians in the intervention arm adopted the new blood-based protein assay. Ordering physicians were 3.88 (95% CI 1.67-9.03) times more likely to order a diagnostic colonoscopy. In percentage terms, those who ordered the assay were more likely to order colonoscopy (92%) than either intervention physicians who did not order the assay (77%) or control physicians (66%) (p < 0.001). A marginal effects estimation showed that use of the assay would increase ordering colonoscopy to nearly 95%.

CONCLUSION

Over one-third of adults in the United States do not follow the recommended screening guidelines for CRC. The introduction of a blood-based protein assay significantly increased the likelihood that physicians would order diagnostic colonoscopies in elevated-risk patients compared to those without access to the assay results. The overall change in clinical utility observed here has the potential to significantly improve clinical care.

Clinical assessment to determine the risk of bowel cancer using Symptoms, Age, Mass and Iron deficiency anaemia (SAMI)

BACKGROUND

The aim of this study was to identify characteristics with independent predictive value for bowel cancer for use in the clinical assessment of patients attending colorectal outpatient clinics.

METHODS

This was a 22-year (1986-2007) retrospective cohort analysis of data collected prospectively from patients who attended colorectal surgical outpatient clinics in Portsmouth. The data set was split randomly into two groups of patients to generate and validate a predictive model. Multivariable logistic regression was used to create and validate a system to predict outcome. Receiver operating characteristic (ROC) curves and Hosmer-Lemeshow test were used to evaluate the model's predictive capability. The likelihood of bowel cancer was expressed as the odds ratio (OR).

RESULTS

Data from 29 005 patients were analysed. Discrimination of the model for bowel cancer was high in the development (C-statistic 0·87, 95 per cent c.i. 0·85 to 0·88) and validation (C-statistic 0·86, 0·84 to 0·87) groups. The most important co-variables in the final model were: age (OR 3·17-27·10), rectal (OR 31·48) or abdominal (OR 1·83-8·45) mass, iron deficiency anaemia (IDA) (OR 4·42-8·38), rectal bleeding and change in bowel habit in combination (OR 5·37), change in bowel habit without rectal bleeding, with or without abdominal pain (OR 2·12-2·52), and rectal bleeding with no perianal symptoms and without change in bowel habit (OR 2·91). Some 91·5 per cent of bowel cancers presented with these characteristics, 40·4 per cent with a mass and/or IDA. In patients with at least one of these characteristics the overall risk of having cancer was 10·0 (range 6·5-50·4) per cent, compared with 1·1 (0·3-2·3) per cent in patients without them.

CONCLUSION

A clinical assessment that systematically identifies or excludes four symptom-age combinations, a mass and IDA (SAMI) stratifies patients as having a low and higher risk of having bowel cancer. This could improve patient selection for referral and investigation.

The global burden of diagnostic errors in primary care

Diagnosis is one of the most important tasks performed by primary care physicians. The World Health Organization (WHO) recently prioritized patient safety areas in primary care, and included diagnostic errors as a high-priority problem. In addition, a recent report from the Institute of Medicine in the USA, 'Improving Diagnosis in Health Care', concluded that most people will likely experience a diagnostic error in their lifetime. In this narrative review, we discuss the global significance, burden and contributory factors related to diagnostic errors in primary care. We synthesize available literature to discuss the types of presenting symptoms and conditions most commonly affected. We then summarize interventions based on available data and suggest next steps to reduce the global burden of diagnostic errors. Research suggests that we are unlikely to find a 'magic bullet' and confirms the need for a multifaceted approach to understand and address the many systems and cognitive issues involved in diagnostic error. Because errors involve many common conditions and are prevalent across all countries, the WHO's leadership at a global level will be instrumental to address the problem. Based on our review, we recommend that the WHO consider bringing together primary care leaders, practicing frontline clinicians, safety experts, policymakers, the health IT community, medical education and accreditation organizations, researchers from multiple disciplines, patient advocates, and funding bodies among others, to address the many common challenges and opportunities to reduce diagnostic error. This could lead to prioritization of practice changes needed to improve primary care as well as setting research priorities for intervention development to reduce diagnostic error.

Comorbid conditions delay diagnosis of colorectal cancer: a cohort study using electronic primary care records

BACKGROUND

Pre-existing non-cancer conditions may complicate and delay colorectal cancer diagnosis.

METHOD

Incident cases (aged ⩾40 years, 2007-2009) with colorectal cancer were identified in the Clinical Practice Research Datalink, UK. Diagnostic interval was defined as time from first symptomatic presentation of colorectal cancer to diagnosis. Comorbid conditions were classified as 'competing demands' (unrelated to colorectal cancer) or 'alternative explanations' (sharing symptoms with colorectal cancer). The association between diagnostic interval (log-transformed) and age, gender, consultation rate and number of comorbid conditions was investigated using linear regressions, reported using geometric means.

RESULTS

Out of the 4512 patients included, 72.9% had ⩾1 competing demand and 31.3% had ⩾1 alternative explanation. In the regression model, the numbers of both types of comorbid conditions were independently associated with longer diagnostic interval: a single competing demand delayed diagnosis by 10 days, and four or more by 32 days; and a single alternative explanation by 9 days. For individual conditions, the longest delay was observed for inflammatory bowel disease (26 days; 95% CI 14-39).

CONCLUSIONS

The burden and nature of comorbidity is associated with delayed diagnosis in colorectal cancer, particularly in patients aged ⩾80 years. Effective clinical strategies are needed for shortening diagnostic interval in patients with comorbidity.

Clinical features of bowel disease in patients aged <50 years in primary care: a large case-control study

Background

Incidences of colorectal cancer (CRC) and inflammatory bowel disease (IBD) are increasing in those aged <50 years.

Aim

To identify and quantify clinical features in primary care of CRC/IBD in those aged <50 years. This study considered the two conditions together and aimed to determine which younger patients, presenting in primary care with symptoms, would benefit from investigation for potentially serious colorectal disease.

Design and setting

Matched case-control study using primary care records from the Clinical Practice Research Datalink, UK.

Method

Incident cases (aged <50 years) of CRC (n = 1661) and IBD (n = 9578) diagnosed between 2000 and 2013 were each matched with up to three controls (n = 3979 CRC; n = 22 947 IBD). Odds ratios (OR) and positive predictive values (PPV) were estimated for features of CRC/IBD in the year before diagnosis.

Results

Ten features were independently associated with CRC/IBD (all P<0.001): rectal bleeding, change in bowel habit, diarrhoea, raised inflammatory markers, thrombocytosis, abdominal pain, low mean cell volume (MCV), low haemoglobin, raised white cell count, and raised hepatic enzymes. PPVs were >3% for rectal bleeding with diarrhoea, thrombocytosis, low MCV, low haemoglobin or raised inflammatory markers; for change in bowel habit with low MCV, thrombocytosis or low haemoglobin; and for diarrhoea with thrombocytosis.

Conclusion

This study quantified the risk of serious bowel disease in symptomatic patients aged <50 years in primary care. Rectal bleeding and change in bowel habit are strongly predictive of CRC/IBD when combined with abnormal haematology. The present findings help prioritise patients for colonoscopy where the diagnosis is not immediately apparent.

Poor predictive value of lower gastrointestinal alarm features in the diagnosis of colorectal cancer in 1981 patients in secondary care

BACKGROUND

Clinicians are advised to refer patients with lower gastrointestinal (GI) alarm features for urgent colonoscopy to exclude colorectal cancer (CRC). However, the utility of alarm features is debated.

AIM

To assess whether performance of alarm features is improved by using a symptom frequency threshold to trigger referral, or by combining them into composite variables, including minimum age thresholds, as recommended by the National Institute for Health and Care Excellence (NICE).

METHODS

We collected data prospectively from 1981 consecutive adults with lower GI symptoms. Assessors were blinded to symptom status. The reference standard to define CRC was histopathological confirmation of adenocarcinoma in biopsy specimens from a malignant-looking colorectal lesion. Controls were patients without CRC. Sensitivity, specificity, positive predictive values (PPVs) and negative predictive values were calculated for individual alarm features, as well as combinations of these.

RESULTS

In identifying 47 (2.4%) patients with CRC, individual alarm features had sensitivities ranging from 11.1% (family history of CRC) to 66.0% (loose stools), and specificities from 30.5% (loose stools) to 75.6% (family history of CRC). Using higher symptom frequency thresholds improved specificity, but to the detriment of sensitivity. NICE referral criteria also had higher specificities and lower sensitivity, with PPVs above 4.8%. More than 80% of those with CRC met at least one of the NICE referral criteria.

CONCLUSIONS

Using higher symptom frequency thresholds for alarm features improved specificity, but sensitivity was low. NICE referral criteria had PPVs above 4.8%, but sensitivities ranged from 2.2% to 32.6%, meaning many cancers would be missed.