Colorectal cancer is a common and important health problem in the UK, where national guidance recommends that people with possible symptoms of colorectal cancer are offered a test of their stool called a quantiative faecal immunochemical test (qFIT). qFIT detects small quantities of blood in the faeces that can indicate the presence of colorectal cancer and other important bowel disease. People with negative tests do not require any further investigation for colorectal cancer and are being looked after by their GP to establish another cause for their symptoms. Although there is good evidence from large studies that this is an appropriate strategy, there is a lack of real-world data on how best to investigate and treat people with ongoing symptoms but a negative qFIT result.
In this faesibility study we aim to establish the quality of data around qFIT results in the CPRD dataset in order to plan a larger analysis of patient outcomes that have negative qFIT results.
Colorectal cancer (CRC) is the fourth most common malignancy in the UK. Despite the national screening programme, most people with CRC will present to their GP with symptoms. Since publication of NICE guidance NG12, quantitative faecal immunochemical tests (qFIT) been progressively rolled out across UK primary care, as a rule out test for most patients with possible symptoms of CRC. This has meant that patients with symptoms of CRC and a negative qFIT– i.e. those who previously were referred for definitive testing – are now being held by primary care.
Our aim in a future study – i.e. if this feasibility study shows that adequate data is recorded in CPRD Aurum - is to estimate the real-world frequency of missed CRC with negative qFIT as well as non-CRC intrabdominal diagnoses such as other cancers, inflammatory bowel disease, and other significant bowel pathology. This feasibility study will have public health impact by determining whether CPRD is a suitable resource for future research on the real-world performance of qFIT – an issue that is important for primary care physicians and patients with symptoms of CRC.
This feasibility study is to establish whether sufficient information is coded within CPRD Aurum on qFIT tests in symptomatic patients. Specifically, whether the quantitative results are recorded and whether they can be distinguished from qFITs used for screening.
The population is all patients, irrespective of age or sex, in whom a qFIT test result is coded in CPRD Aurum between 01/01/2018 to 01/01/2024. For the feasibility study we will assess data quality and basic demographics only. Specifically, the proportion of patients with a recorded quantitative result versus a binary positive/negative; whether these can be distinguished from screening qFITs by the positive threshold (10 versus 100μgHb/g); and the age/sex distribution of these patients and their symptoms/signs (n, %)
Quantitative faecal immunochemcial test results; recorded symptoms and signs in the CPRD Aurum Observation table that correspond with the NICE guidance on suspected colorectal cancer - namely, weight loss, abdominal pain, rectal bleeding, change in bowel habit and iron-deficiency anaemia.
Jessica Watson - Chief Investigator - University of Bristol
Lewis Buss - Corresponding Applicant - University of Bristol