Curative resectability of gastrointestinal cancer identified from iron deficiency anemia

Development and validation of a faecal immunochemical test-based model in the work-up of patients with iron deficiency anaemia

Objective

In patients with iron deficiency anaemia (IDA), the diagnostic yield of gastroscopy and colonoscopy (bidirectional endoscopy) in detecting neoplastic lesions is low. This study aimed to develop and validate a faecal immunochemical test (FIT)-based model to optimise the work-up of patients with IDA.

Methods

Outpatients with IDA were enrolled in a prospective, multicentre study from April 2016 to October 2019. One FIT was performed before bidirectional endoscopy. Significant gastrointestinal lesions were recorded and a combined model developed with variables that were independently associated with significant colorectal lesions in the multivariate analysis. The model cut-off was selected to provide a sensitivity of at least 95% for colorectal cancer (CRC) detection, and its performance was compared to different FIT cut-offs. The data set was randomly split into two groups (developed and validation cohorts). An online calculator was developed for clinical application.

Results

The development and validation cohorts included 373 and 160 patients, respectively. The developed model included FIT value, age, and sex. In the development and validation cohorts, a model cut-off of 0.1375 provided a negative predictive value of 98.1 and 96.7% for CRC and 90.7 and 88.3% for significant colorectal lesions, respectively. This combined model reduced the rate of missed significant colorectal lesions compared to FIT alone and could have avoided more than one-fourth of colonoscopies.

Conclusion

The FIT-based combined model developed in this study may serve as a useful diagnostic tool to triage IDA patients for early endoscopic referral, resulting in considerable reduction of unnecessary colonoscopies.

The use of faecal immunochemical testing in the decision-making process for the endoscopic investigation of iron deficiency anaemia

Background Blood loss from the gastrointestinal (GI) tract is the most common cause of iron deficiency anaemia (IDA) in adult men and postmenopausal women. Gastroduodenal endoscopy (GDE) and colonoscopy are frequently recommended, despite uncertainty regarding the coexistence of lesions in the upper and lower GI tract. The faecal immunochemical test (FIT) measures the concentration of faecal haemoglobin (f-Hb) originating only from the colon or rectum. We aimed to assess whether the FIT was able to select the best endoscopic procedure for detecting the cause of IDA. Methods A prospective study of 120 men and postmenopausal women referred for a diagnostic study of IDA were evaluated with an FIT, GDE and colonoscopy. The endoscopic finding of a significant upper lesion (SUL) or a significant bowel lesion (SBL) was considered to be the cause of the IDA. Results The diagnoses were 35.0% SUL and 20.0% SBL, including 13.3% GI cancer. In the multivariate analysis, the concentration of blood haemoglobin (b-Hb) <9 g/dL (OR: 2.60; 95% CI 1.13-6.00; p = 0.025) and non-steroidal anti-inflammatory drugs NSAIDs (2.56; 1.13-5.88; p = 0.024) were associated with an SUL. Age (0.93; 0.88-0.99; p = 0.042) and f-Hb ≥ 15 μg Hb/g faeces (38.53; 8.60-172.50; p < 0.001) were associated with an SBL. A "FIT plus gastroscopy" strategy, in which colonoscopy is performed only when f-Hb ≥15 μg Hb/g faeces, would be able to detect 92.4% of lesions and be 100% accurate in the detection of cancer while avoiding 71.6% of colonoscopies. Conclusions The FIT is an accurate method for selecting the best endoscopy study for the evaluation of IDA. An FIT-based strategy is more cost-effective than the current bidirectional endoscopy-based strategy and could improve endoscopic resource allocation.