Evaluation of a fecal immunochemistry test prior to colonoscopy for outpatients with various indications

Faecal immunochemical tests can improve colonoscopy triage in patients with iron deficiency: A systematic review and meta-analysis

BACKGROUND

Use of the faecal immunochemical test (FIT) to triage patients with iron deficiency (ID) for colonoscopy due to suspected colorectal cancer (CRC) may improve distribution of colonoscopic resources. We reviewed the diagnostic performance of FIT for detecting advanced colorectal neoplasia, including CRC and advanced pre-cancerous neoplasia (APCN), in patients with ID, with or without anaemia.

METHODS

We performed a systematic review of three databases for studies comprising of patients with ID, with or without anaemia, completing a quantitative FIT within six months prior to colonoscopy, where test performance was compared against the reference standard colonoscopy. Random effects meta-analyses determined the diagnostic performance of FIT for advanced colorectal neoplasia.

RESULTS

Nine studies were included on a total of n=1761 patients with ID, reporting FIT positivity thresholds between 4-150 µg haemoglobin/g faeces. Only one study included a non-anaemic ID (NAID) cohort. FIT detected CRC and APCN in ID patients with 90.7 % and 49.3 % sensitivity, and 81.0 % and 82.4 % specificity, respectively. FIT was 88.0 % sensitive and 83.4 % specific for CRC in patients with ID anaemia at a FIT positivity threshold of 10 µg haemoglobin/g faeces.

CONCLUSIONS

FIT shows high sensitivity for advanced colorectal neoplasia and may be used to triage those with ID anaemia where colonoscopic resources are limited, enabling those at higher risk of CRC to be prioritised for colonoscopy. There is a need for further research investigating the diagnostic performance of FIT in NAID patients.

Comprehensive analysis of 5-hydroxymethylcytosine in zw10 kinetochore protein as a promising biomarker for screening and diagnosis of early colorectal cancer

BACKGROUND

As a new epigenetic biomarker, 5-hydroxymethylcytosine (5hmC) is broadly involved in various diseases including cancers. However, the function and diagnostic performance of 5hmC in colorectal cancer (CRC) remain unclear.

RESULTS

High-throughput sequencing was used to profile 5hmC levels in adjacent normal colon, advanced adenomas, and CRC. The expression and 5hmC levels in zw10 kinetochore protein (ZW10) were significantly increased in the tissues and blood samples for patients with advanced adenoma and CRC, and were much higher in the early stages of CRC (I and II). The receiver operating characteristic analysis had potential diagnostic value for CRC. The area under the curve (AUC) of ZW10 5hmC levels in tissue samples of CRC was 0.901. In blood samples, the AUC was 0.748 for CRC. In addition, the ZW10 5hmC level had much higher diagnostic performance in early stages of CRC (AUC = 0.857) than it did in advanced stages (AUC = 0.594). Compared with FHC cell, ZW10 expression in HT29 cell was significantly increased. The ZW10 knockdown could inhibit cell proliferation and the ZW10 overexpression could promote cell proliferation in HT-29 cell. Furthermore, ZW10 knockdown inhibited AKT and mTOR phosphorylation, and ZW10 overexpression promoted AKT and mTOR phosphorylation.

CONCLUSIONS

The ZW10 5hmC level may serve as an effective epigenetic biomarker for minimally invasive screening and diagnosis of CRC, and it has higher diagnostic performance in early stages of CRC than it does in advanced stages. In addition, ZW10 could regulate CRC progression through the AKT-mTOR signaling.

FIT negative cancers: A right-sided problem? Implications for screening and whether iron deficiency anaemia has a role to play

INTRODUCTION

Faecal Immunohistochemistry Testing (FIT) is recommended as an adjunct to guide referrals from Primary Care for individuals without rectal bleeding, who do not meet the suspected cancer pathway referral guidelines. It has largely replaced Faecal Occult Blood Testing.

AIMS

To assess the specificity of FIT. To understand the characteristics of FIT negative cancer patients and whether they have predominantly right sided cancers. Evaluating the efficacy of FIT and Iron deficiency anaemia in combination to capture patients with colorectal cancers.

METHODS

A study of 1000 symptomatic patients, undergoing FIT by Clinicians during the 'Digital rectal examination'. Inclusion criteria; all patients referred via our cancer referral pathway. FIT positivity was set at 10 μg g of faeces.

RESULTS

There were 7 FIT negative cancers in this cohort; 1 was a lymphoma and the other 6 were caecal adenocarcinomas. 5 were anaemic. The positive predictive value of IDA was 34% compared with 'other symptoms'; 18%. The negative predictive value of FIT was 99.05% in this cohort. Specificity for FIT was 86.9% (CI 96%).

CONCLUSION

Two separate referral pathways for IDA and FIT positive tests, would have captured all patients except 2; the lymphoma and 1 advanced caecal adenocarcinoma. FIT is an excellent triage tool prior to colonoscopy however capturing right sided disease remains a weak point. Multivariate analysis of patients in addition to IDA and FIT should improve capture of this subgroup.