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

Analytical evaluation of eight qualitative FIT for haemoglobin products, for professional use in the UK

OBJECTIVES

Qualitative faecal immunochemical tests for haemoglobin (FIT), for triaging for colorectal cancer investigations, are available for professional use. The aim was to evaluate these lateral flow tests. No previous analytical evaluations have been published.

METHODS

Analytical sensitivity (AS) was assessed using samples spanning manufacturers' quoted AS, concurrently with the quantitative OC-SENSOR PLEDIA, using Hb-spiked samples in manufacturers' buffer (n≥5; ≤9-99 ng Hb/mL buffer), Hb-spiked faeces (n=6; <2-34 µg Hb/g faeces) and natural faeces (n=17; <2-82 μg/g); concentrations for 50 %/100 % Hb-detected were compared with quoted AS. Compatibility with two external quality assessment schemes (EQAS) (n=9; 3-96 μg/g) and prozone compared with manufacturers limits (n=9; 2,500-10,000,000 ng/mL) were tested. Ease-of-use by five healthcare personnel was assessed.

RESULTS

Seven products showed lower AS (ng/mL) than manufacturers quoted using Hb-spiked aqueous samples compared with OC-SENSOR, one was equivocal; six manufacturers quoted AS in µg/g, five showed lower AS using Hb-spiked faeces. Results were similar but less consistent for natural faeces. Result lines for low concentrations can be faint and open to interpretation. Results were consistent with manufacturers quoted prozone limits. Results were consistent for seven products for two EQAS. The ease-of-use was 68.5-85.6 %; products with lower scores could be improved with better instructions and sample bottles.

CONCLUSIONS

AS was lower for seven products (aqueous samples) and five products (aqueous/faecal samples) and prozone consistent with manufacturers expected concentrations, compared with OC-SENSOR. EQAS results were mostly consistent with expected results; products can be used by healthcare professionals, though some manufacturer improvements could be made.

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

BACKGROUND

Faecal immunochemical testing (FIT) is widely used in bowel screening programmes and assessing symptomatic patients for suspected colorectal cancer (CRC). The evidence for single test performance of FIT in both settings is considerable; however, the use of a repeat test to increase sensitivity remains uncertain. We aimed to review what increase in test positivity would be generated by additional FITs, whether a repeated FIT detects previously missed CRC and advanced colorectal neoplasia (ACRN), and to estimate the sensitivity of double-FIT strategies to diagnose CRC and ACRN.

METHODS

A systematic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) was performed using key search terms. Studies reporting the use of more than one FIT in the same screening round or planned assessment of a single symptomatic patient episode were included. Studies were categorised by the reported study population into asymptomatic, mixed (cohorts of combined asymptomatic, symptomatic, or high-risk surveillance), or symptomatic cohorts.

RESULTS

A total of 68 studies were included for analysis (39 asymptomatic, 21 mixed, 7 symptomatic, and 1 study with discrete asymptomatic and symptomatic data). At a threshold of 10 µg Hb/g, the two-test positivity ranged between 8.1 and 34.5%, with an increase from the second test of 3-9.2 percentage points. Four out of five studies comparing one versus two tests for diagnosing CRC at 10 µg Hb/g identified additional cases with the second test, with a minimum of 50% reduction in missed CRC. At a threshold of 20 µg Hb/g, the second test increased the positivity by 1.3-6.7 percentage points, with a two-test positivity of between 5.1 and 25.0%. Using a threshold of 20 µg Hb/g, five out of seven studies had a 25% reduction in missed CRC. A meta-analysis estimated the double-FIT sensitivity at 10 µg Hb/g for CRC in mixed-risk and symptomatic cohorts to be 94% and 98%, respectively.

CONCLUSIONS

Repeated use of FIT helps to diagnose more cases of CRC with a moderate increase in positivity. A double-FIT strategy at 10 µg Hb/g in mixed and symptomatic cohorts has a very high sensitivity for CRC.

Survival After Wait-and-See Approach in Older Patients With Unexplained Iron Deficiency Anemia in Primary Care: A Practice Evaluation

OBJECTIVES

Guidelines recommend upper and lower gastrointestinal endoscopic evaluation for patients without a clear physiological explanation for iron deficiency anemia (IDA). However, the consequences of watchful waiting in older patients with unexplained IDA in general practice are unknown. The aim of this study was to investigate characteristics and survival of patients with an unexplained IDA in general practice who refrain from medical specialist evaluation.

DESIGN

Historical prospective study.

SETTING AND PARTICIPANTS

Patients aged ≥70 years with IDA coded in their medical records were selected from the Dutch Academic General Practitioner Development Network (AHON) database.

METHODS

Based on their medical records, patients with an unexplained IDA were classified as (1) referred for medical specialist evaluation, or (2) no or noninvasive evaluation in general practice.

RESULTS

Compared to patients who were referred for medical specialist evaluation (n = 235, 47.8%), patients who had no or noninvasive evaluation (n = 257; 52.5%) were older (median respectively 79 vs 82 years old, P < .01) and more likely to have congestive heart failure (respectively 17.4% and 26.1%, P = .02) and dementia (respectively 2.6% and 8.9%, P < .01). Two-year survival was significantly higher in patients who were referred for medical specialist evaluation compared to patients who had no or noninvasive evaluation (respectively, 83.9% and 75.5%, P = .02).

CONCLUSIONS AND IMPLICATIONS

Although mortality was significantly higher in the older and more comorbid patients who had no or noninvasive evaluation in general practice, survival was still high in this patient group. Therefore, non-guideline adherence and a wait-and-see approach could be discussed in a shared-decision-making consultation.

The performance of FIT-based and other risk prediction models for colorectal neoplasia in symptomatic patients: a systematic review

Background

Colorectal cancer (CRC) incidence and mortality are increasing internationally. Endoscopy services are under significant pressure with many overwhelmed. Faecal immunochemical testing (FIT) has been advocated to identify a high-risk population of symptomatic patients requiring definitive investigation by colonoscopy. Combining FIT with other factors in a risk prediction model could further improve performance in identifying those requiring investigation most urgently. We systematically reviewed performance of models predicting risk of CRC and/or advanced colorectal polyps (ACP) in symptomatic patients, with a particular focus on those models including FIT.

Methods

The review protocol was published on PROSPERO (CRD42022314710). Searches were conducted from database inception to April 2023 in MEDLINE, EMBASE, Cochrane libraries, SCOPUS and CINAHL. Risk of bias of each study was assessed using The Prediction study Risk Of Bias Assessment Tool. A narrative synthesis based on the guidelines for Synthesis Without Meta-Analysis was performed due to study heterogeneity.

Findings

We included 62 studies; 23 included FIT (n = 22) or guaiac Faecal Occult Blood Testing (n = 1) combined with one or more other variables. Twenty-one studies were conducted solely in primary care. Generally, prediction models including FIT consistently had good discriminatory ability for CRC/ACP (i.e. AUC >0.8) and performed better than models without FIT although some models without FIT also performed well. However, many studies did not present calibration and internal and external validation were limited. Two studies were rated as low risk of bias; neither model included FIT.

Interpretation

Risk prediction models, including and not including FIT, show promise for identifying those most at risk of colorectal neoplasia. Substantial limitations in evidence remain, including heterogeneity, high risk of bias, and lack of external validation. Further evaluation in studies adhering to gold standard methodology, in appropriate populations, is required before widespread adoption in clinical practice.

Funding

National Institute for Health and Care Research (NIHR) [Health Technology Assessment Programme (HTA) Programme (Project number 133852).

Colorectal Cancer Fast Tracks: Cancer Yield and the Predictive Value of Entry Criteria

BACKGROUND

Fast-track pathways for diagnosing colorectal cancer (CRC) have been implemented in several European countries. In Sweden, a substantial number of CRC are diagnosed via the Swedish Standardized Course of Care for colorectal cancer (SCC-CRC). We evaluated the SCC-CRC in terms of CRC yield, and predictive values and odds ratios (OR) for the entry criteria.

METHODS

We retrospectively analyzed all 2539 patients referred for SCC-CRC colonoscopy between September 2016 and December 2020. Entry criteria and colonoscopy outcomes were analyzed.

RESULTS

CRC yield was 16.4%. Highest positive predictive values (PPVs) were seen for abnormal radiology (PPV 30.5%, OR 4.7 (95% CI 3.4-6.4) p < 0.001), abnormal rectal examination (PPV 28%, OR 3.6 (95% CI 2.7-4.8) p < 0.001), and anemia (PPV 24.8%, OR 2.2 (95% CI 1.5-3.1) p < 0.001). Some entry criteria showed no significant risk increase, i.e., visible blood in stool/rectal bleeding, change in bowel habits, and the combination of changed bowel habits plus anemia. A positive fecal immunochemical test (FIT), although not part of the SCC-CRC, showed the highest OR: 9.9 (95% CI 4.5-21.7) p < 0.001) and PPV of 18.8%.

CONCLUSIONS

CRC yield from the SCC-CRC is slightly higher compared to other European fast tracks. A number of entry criteria showed no benefit towards assessing CRC risk. FIT testing should be included in CRC fast tracks to increase diagnostic efficacy.

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.

Who are the patients being offered the faecal immunochemical test in routine English general practice, and for what symptoms? A prospective descriptive study

OBJECTIVES

The faecal immunochemical test (FIT) was introduced to triage patients with lower-risk symptoms of colorectal cancer (CRC) in English primary care in 2018. While there is growing evidence on its utility to triage patients in this setting, evidence is still limited on how official FIT guidance is being used, for which patients and for what symptoms. We aimed to investigate the use of FIT in primary care practice for lower-risk patients who did not immediately meet criteria for urgent referral.

DESIGN

A prospective, descriptive study of symptomatic patients offered a FIT in primary care between January and June 2020.

SETTING

East of England general practices.

PARTICIPANTS

Consenting patients (aged ≥40 years) who were seen by their general practitioners (GPs) with symptoms of possible CRC for whom a FIT was requested. We excluded patients receiving a FIT for asymptomatic screening purposes, or patients deemed by GPs as lacking capacity for informed consent. Data were obtained via patient questionnaire, medical and laboratory records.

PRIMARY AND SECONDARY OUTCOME MEASURES

FIT results (10 µg Hb/g faeces defined a positive result); patient sociodemographic and clinical characteristics; patient-reported and GP-recorded symptoms, symptom severity and symptom agreement between patient and GP (% and kappa statistics).

RESULTS

Complete data were available for 310 patients, median age 70 (IQR 61-77) years, 53% female and 23% FIT positive. Patients most commonly reported change in bowel habit (69%) and fatigue (57%), while GPs most commonly recorded abdominal pain (25%) and change in bowel habit (24%). Symptom agreement ranged from 44% (fatigue) to 80% (unexplained weight loss). Kappa agreement was universally low across symptoms.

CONCLUSION

Almost a quarter of this primary care cohort of symptomatic patients with FIT testing were found to be positive. However, there was low agreement between patient-reported and GP-recorded symptoms. This may impact cancer risk assessment and optimal patient management in primary care.

Diagnostic accuracy for colorectal cancer of a quantitative faecal immunochemical test in symptomatic primary care patients: a study protocol

BACKGROUND

There is increasing evidence supporting the use of faecal immunochemical tests (FIT) in patients reporting symptoms associated with colorectal cancer (CRC), but most studies until now have focused on selected subjects already referred for investigation. We therefore set out to determine the accuracy and predictive values of FIT in a primary care population.

METHOD

A prospective, multicentre, single-gated comparative diagnostic study on quantitative FIT in patients aged 40 years and above presenting in primary care with symptoms associated with CRC will be conducted. Patients representing the whole spectrum of severity of such symptoms met with in primary care will be eligible and identified by GPs. Participants will answer a short form on symptoms during the last month. They will provide two faecal samples from two separate days. Analyses will be performed within 5 days (QuikRead go®, Aidian Oy). The analytical working range is 10-200 μg Hb/g faeces. Reference test will be linked to the Swedish Colorectal Cancer Registry up to 2 years after inclusion. Accuracy, area under ROC curves, and predictive values will be calculated for one FIT compared to the highest value of two FIT and at cutoff < 10, 10-14.9, 15-19.9 and ≥ 20 μg Hb/g faeces. Subgroup analyses will be conducted for patients with anaemia and those reporting rectal bleeding. A model-based cost-effectiveness analysis based on the clinical accuracy study will be performed. Based on previous literature, we hypothesized that the sensitivity of the highest value of two FIT at cutoff 10 μg Hb/g faeces will be 95% (95% CI + / - 15%). The prevalence of CRC in the study population was estimated to be 2%, and the rate of non-responders to be 1/6. In all, 3000 patients will be invited at 30 primary care centres.

DISCUSSION

This study will generate important clinical real-life structured data on accuracy and predictive values of FIT in the most critical population for work-up of CRC, i.e. patients presenting with at times ambiguous symptoms in primary care. It will help establish the role of FIT in this large group.

TRIAL REGISTRATION

NCT05156307 . Registered on 14 December 2021-retrospectively registered.

Faecal immunochemical tests safely enhance rational use of resources during the assessment of suspected symptomatic colorectal cancer in primary care: systematic review and meta-analysis

OBJECTIVE

Implementation of faecal immunochemical tests (FIT) as a triage test in primary healthcare may improve the efficiency of referrals without missing cases of colorectal cancer (CRC). We aim to summarise the performance characteristics of FITs for CRC in symptomatic patients presenting to primary healthcare.

DESIGN

We performed a systematic literature review of Medline and EMBASE databases from May 2018 to November 2020. Previous related systematic searches were also adapted to this aim and completed with reference screening. We identified studies performed on adult patients consulting for abdominal symptoms in primary care which reported data such that the FIT diagnostic performance parameters for CRC could be obtained. Bivariate models were used to synthesise available evidence. Meta-regression analysis was performed to evaluate the causes of heterogeneity.

RESULTS

Twenty-three studies (69 536 participants) were included (CRC prevalence 0.3%-6.2%). Six studies (n=34 691) assessed FIT as rule in test (threshold of ≥150 µg Hb/g faeces) showing a sensitivity of 64.1% (95% CI 57.8% to 69.9%) and a specificity of 95.0% (95% CI 91.2% to 97.2%). A threshold of 10 µg/g (15 studies; n=48 872) resulted in a sensitivity of 87.2% (95% CI 81.0% to 91.6%) and a specificity of 84.4% (95% CI 79.4% to 88.3%) for CRC. At a 20 µg Hb/g faeces threshold (five studies; n=24 187) less than one additional CRC would be missed per 1000 patients investigated compared with 10 µg Hb/g faeces threshold (CRC prevalence 2%).

CONCLUSION

FIT is the test of choice to evaluate patients with new-onset lower gastrointestinal symptoms in primary healthcare.

Faecal immunochemical test for patients with 'high-risk' bowel symptoms: a large prospective cohort study and updated literature review

Background

We evaluated whether faecal immunochemical testing (FIT) can rule out colorectal cancer (CRC) among patients presenting with ‘high-risk’ symptoms requiring definitive investigation.

Methods

Three thousand five hundred and ninety-six symptomatic patients referred to the standard urgent CRC pathway were recruited in a multi-centre observational study. They completed FIT in addition to standard investigations. CRC miss rate (percentage of CRC cases with low quantitative faecal haemoglobin [f-Hb] measurement) and specificity (percentage of patients without cancer with low f-Hb) were calculated. We also provided an updated literature review.

Results

Ninety patients had CRC. At f-Hb < 10 µg/g, the miss rate was 16.7% (specificity 80.1%). At f-Hb < 4 µg/g, the miss rate was 12.2% (specificity 73%), which became 3.3% if low FIT plus the absence of anaemia and abdominal pain were considered (specificity 51%). Within meta-analyses of 9 UK studies, the pooled miss rate was 7.2% (specificity 74%) for f-Hb < 4 µg/g.

Discussion

FIT alone as a triage tool would miss an estimated 1 in 8 cases in our study (1 in 14 from meta-analysis), while many people without CRC could avoid investigations. FIT can focus secondary care diagnostic capacity on patients most at risk of CRC, but more work on safety netting is required before incorporating FIT triage into the urgent diagnostic pathway.

Diagnostic accuracy of point of care faecal immunochemical testing using a portable high-speed quantitative analyser for diagnosis in 2-week wait patients

AIM

Laboratory-based faecal immunochemical testing (FIT) is the gold standard for detecting the presence of blood in the stool. The aim was to perform a diagnostic accuracy study to confirm if a point of care (POC) analyser for FIT could be safely used as an adjunct in the triage and management of 2-week wait (TWW) colorectal patients.

METHODS

The Point of Care Faecal Immunochemical Testing (POC FIT) prospective observational cohort study was designed for TWW patients at a regional referral centre. Between July 2019 and March 2020, patients were invited to perform and bring a FIT sample to clinic. FIT was completed within the clinic appointment using a POC quantitative analyser that has a 2-min processing time (QuikRead go®). Patients and clinicians were blinded to results within the clinic appointment. The results were compared with subsequent diagnostic outcomes. Faecal haemoglobin of <10 µg haemoglobin/g of faeces was considered a negative result. Sensitivities for colorectal cancer (CRC) and combined serious bowel disease (SBD) were calculated using this pre-determined cut-off.

RESULTS

A total of 553 patients were included for analytical comparison with diagnostic outcomes. There were 14 (2.5%) patients with CRC and 52 (9.4%) with SBD. The sensitivities for CRC and SBD were 92.9% (95% CI 68.5%-98.7%) and 76.9% (95% CI 63.9%-86.3%) respectively. 379 (68.5%) patients had a negative FIT result (negative predictive value for CRC was 99.7%).

CONCLUSIONS

This POC FIT device is a useful adjunct to better manage TWW patients. The high observed sensitivity for CRC offers opportunities, within a single consultation, for improved triage and rationalization of investigation for those with bowel symptoms.

Symptoms and signs of colorectal cancer, with differences between proximal and distal colon cancer: a prospective cohort study of diagnostic accuracy in primary care

BACKGROUND

In an abdominal symptom study in primary care in six European countries, 511 cases of cancer were recorded prospectively among 61,802 patients 16 years and older in Norway, Denmark, Sweden, Netherlands, Belgium and Scotland. Colorectal cancer is one of the main types of cancer associated with abdominal symptoms; hence, an in-depth subgroup analysis of the 94 colorectal cancers was carried out in order to study variation in symptom presentation among cancers in different anatomical locations.

METHOD

Initial data capture was by completion of standardised forms containing closed questions about symptoms recorded during the consultation. Follow-up data were provided by the GP after diagnosis, based on medical record data made after the consultation. GPs also provided free text comments about the diagnostic procedure for individual patients. Fisher's exact test was used to analyse differences between groups.

RESULTS

Almost all symptoms recorded could indicate colorectal cancer. 'Rectal bleeding' had a specificity of 99.4% and a PPV of 4.0%. Faecal occult blood in stool (FOBT) or anaemia may indicate gastrointestinal bleeding: when these symptoms and signs were combined, sensitivity reached 57.5%, with 69.2% for cancer in the distal colon. For proximal colon cancers, none of 18 patients had 'Rectal bleeding' at the initial consultation, but three of the 18 did so at a later consultation. 'Abdominal pain, lower part', 'Constipation' and 'Distended abdomen, bloating' were less specific and also less sensitive than 'Rectal bleeding', and with PPV between 0.7% and 1.9%.

CONCLUSIONS

Apart from rectal bleeding, single symptoms did not reach the PPV 3% NICE threshold. However, supplementary information such as a positive FOBT or persistent symptoms may revise the PPV upwards. If a colorectal cancer is suspected by the GP despite few symptoms, the total clinical picture may still reach the NICE PPV threshold of 3% and justify a specific referral.

The effectiveness of the colorectal cancer referral pathway - identification of colorectal cancer in a Swedish region

INTRODUCTION

To shorten the time for diagnosis of suspected colorectal cancer (CRC), a standardized colorectal cancer referral pathway (CCRP) was introduced in Sweden in September 2016. However, the effects of the CCRP are still uncertain, and CRC is also found in patients undergoing a routine colonoscopy.

OBJECTIVE

To identify all CRC-cases in the Region Örebro County and to investigate via which diagnostic pathway they were diagnosed. Furthermore, to investigate the reasons for and possible effect of not being included in the CCRP for cases found via colonoscopy.

METHODS

Review of medical records of patients with CRC referred to the department of surgery in the Region Örebro County in 2016-2018 (n = 459).

RESULTS

In CRC-cases found through colonoscopy (n = 347), 37.5% were diagnosed via a routine waiting list and 62.5% within the CCRP. No difference in tumor stage or tumor grade was found between the two groups. The non-CCRP showed a longer time to diagnosis than the CCRP group (21.5 days, IQR 7-43 vs. 13 days, IQR 8-17 (p < .001), respectively). Non-rectal cancer was more common in the non-CCRP group (81.5% vs. 57.6%, p < .001). The non-CCRP group had lower median Hb-value (106, IQR 87-129 vs. 117, IQR 101-136, p = .001). 85% of the non-CCRP group was found to meet one or more CCRP referral criteria, with bleeding anemia being the dominant criterion to meet.

CONCLUSION

The CCRP did not appear to improve prognostic outcomes for CRC-patients. ClinicalTrials.gov Identifier: NCT04585516.

Recognising Colorectal Cancer in Primary Care

Colorectal cancer (CRC) is the third most common cancer worldwide. Primary care professionals can play an important role in both prevention and early detection of CRC. Most CRCs are attributed to modifiable lifestyle factors, which can be addressed within primary care, and promotion of population-based screening programmes can aid early cancer detection in asymptomatic patients. Primary care professionals have a vital role in clinically assessing patients presenting with symptoms that may indicate cancer, as most patients with CRC first present with symptoms. These assessments are often challenging—many of the symptoms of CRC are non-specific and commonly occur in patients presenting with non-malignant disease. The range of options for investigating symptomatic patients in primary care is rapidly growing. Simple tests, such as faecal immunochemical testing (FIT), are now being used to guide decisions around referral for more invasive tests, such as colonoscopy, while direct access to specialist investigations is also becoming more common. Clinical decision support tools (CDSTs) which calculate cancer risk based on symptomatology, patient characteristics and test results can provide an additional resource to guide decisions on further investigation. This article explores the challenges of CRC prevention and detection from the primary care perspective, discusses current evidence-based approaches for CRC detection used in primary care (with examples from UK guidelines), and highlights emerging research which may likely alter practice in the future.