Use of iFOBT in Patients Presenting With Alarm Symptoms of Colorectal Cancer

Background: Colorectal cancer (CRC) is one of the most common types of cancer in Denmark, and mortality among patients is high. Patients presenting with alarm symptoms of CRC are referred to colonoscopy in the cancer patient pathway for CRC. However, the proportion of patients with alarm symptoms who have CRC is below 10%. Simultaneously, the burden on endoscopy units to conduct fast-track colonoscopies is growing. Occult blood in the faeces may be an early sign of cancer or precancerous lesions, and can be detected by an immunochemical faecal occult blood test (iFOBT). Few studies have examined the diagnostic properties of the iFOBT among symptomatic patients, and reported sensitivities ranging from 88%-100%, specificities from 77%-94%, and negative predictive values from 98%-100%. These results were derived from diverse patient populations, and used different cut-offs to define positive test results. Using iFOBT may be a valuable tool for the GP when deciding on referral of the patient to the cancer patient pathway. However, evidence is needed on the diagnostic accuracy of the test to detect CRC among patients presenting with alarm symptoms. Hypothesis: In patients presenting with alarm symptoms of CRC, detection of faecal occult blood by iFOBT is an accurate measure of the presence of colonic lesions. Aim: The aim of the study is to examine the diagnostic accuracy of the iFOBT among symptomatic patients referred to colonoscopy in the cancer patient pathway for CRC. Materials and methods: The project is conducted as a diagnostic accuracy study. Patients appointed for colonoscopy will be invited to collect a faecal sample and mail it for analysis. The iFOBT result will be registered in a computer-based laboratory information system. The result of the colonoscopy will be registered in Danish national health registries. The sensitivity, specificity, positive predictive value and negative predictive value will be calculated as measures of the diagnostic properties of the iFOBT, using the result of colonoscopy as the reference standard. The accuracy of the test by type of alarm symptom will also be assessed. Perspectives: The study will provide new and valuable data to evaluate the referral criteria for the cancer patient pathway. Given a good discriminatory ability of the iFOBT among symptomatic patients, fast-track colonoscopy may not be necessary as a first-choice examination in the diagnostic work-up of these patients.

Sex

All

Minimum age

40 Years

Inclusion Criteria:

* Referred by a GP in the Central Denmark Region to colonoscopy in the cancer patient pathway for colorectal cancer.

Exclusion Criteria:

* Referred to colonoscopy in the cancer patient pathway due to non-alarm symptoms.