The fecal hemoglobin concentration, age and sex test score: Development and external validation of a simple prediction tool for colorectal cancer detection in symptomatic patients

Abstract

Prediction models for colorectal cancer (CRC) detection in symptomatic patients, based on easily obtainable variables such as fecal haemoglobin concentration (f-Hb), age and sex, may simplify CRC diagnosis. We developed, and then externally validated, a multivariable prediction model, the FAST Score, with data from five diagnostic test accuracy studies that evaluated quantitative fecal immunochemical tests in symptomatic patients referred for colonoscopy. The diagnostic accuracy of the Score in derivation and validation cohorts was compared statistically with the area under the curve (AUC) and the Chi-square test. 1,572 and 3,976 patients were examined in these cohorts, respectively. For CRC, the odds ratio (OR) of the variables included in the Score were: age (years): 1.03 (95% confidence intervals (CI): 1.02-1.05), male sex: 1.6 (95% CI: 1.1-2.3) and f-Hb (0-<20 µg Hb/g feces): 2.0 (95% CI: 0.7-5.5), (20-<200 µg Hb/g): 16.8 (95% CI: 6.6-42.0), ≥200 µg Hb/g: 65.7 (95% CI: 26.3-164.1). The AUC for CRC detection was 0.88 (95% CI: 0.85-0.90) in the derivation and 0.91 (95% CI: 0.90-093; p = 0.005) in the validation cohort. At the two Score thresholds with 90% (4.50) and 99% (2.12) sensitivity for CRC, the Score had equivalent sensitivity, although the specificity was higher in the validation cohort (p < 0.001). Accordingly, the validation cohort was divided into three groups: high (21.4% of the cohort, positive predictive value-PPV: 21.7%), intermediate (59.8%, PPV: 0.9%) and low (18.8%, PPV: 0.0%) risk for CRC. The FAST Score is an easy to calculate prediction tool, highly accurate for CRC detection in symptomatic patients.

Impact of introducing a faecal immunochemical test (FIT) for haemoglobin into primary care on the outcome of patients with new bowel symptoms: a prospective cohort study

“…Future research should focus on refining the predictive value of an elevated f-Hb, and on whether FIT could be used as a ‘rule-out’ test in any other patient groups referred for colonoscopy. Moreover, it might be that other approaches, including risk scoring using additional variables to the f-Hb, such as the Faecal Haemoglobin Concentration, Age and Sex Test score, have advantages in this clinical setting30: further research is required.…”

Faecal immunochemical tests (FIT) in the assessment of patients presenting with lower bowel symptoms: Concepts and challenges

“…Such risk scoring approaches do exist and have been recently reviewed. 51 Only a few of the models suggested incorporate f-Hb, examples being the COLONPREDICT approach 52 and the FAST Score developed with much input from research centres in Scotland: 53 their application in routine clinical care has not yet been established.…”

Faecal haemoglobin concentration and personalised assessment of the risk of colorectal neoplasia

“…Would readily available data such as age and sex, which have been shown to affect f-Hb (7,8) be usefully incorporated in a risk-based screening algorithm as suggested a number of times (14,17) and already shown to be potentially useful in use of f-Hb in the assessment of patients presenting with symptoms of CRC (18). This would be both simple and inexpensive but, as suggested, further research is necessary to determine the benefits of more complex algorithms incorporating variables other than f-Hb (14).…”