The faecal immunochemical test (FIT) - which works by detecting microscopic levels of blood in faeces - could be effectively used as a 'rule-in' test to detect colorectal cancer and other serious bowel diseases in patients with non-alarming symptoms, researchers said.
A year-long study conducted in Denmark found that the use of a FIT helped GPs to diagnose the majority (67%) of colorectal cancer cases in early stages one and two, increasing patients’ chance of a full recovery.
The research, which was published in the British Journal of Cancer, is the first study to investigate the use of a low-cost FIT in patients presenting with non-alrm symptoms of colorectal cancer.
The researchers said that the majority of new colorectal cancer cases were found on symptomatic presentation in general practice and around 50% of these patients present with symptoms and signs that do not qualify for urgent referral.
'For these patients, the GP will often use a "wait and see" and safety netting approach, which is reflected in a longer diagnostic process compared to patients with alarm symptoms. This may lead to stage progression and ultimately to poorer prognosis. New diagnostic strategies could contribute to [and] aid the GP in the diagnostic work-up of patients with non-alarm symptoms of colorectal cancer,' the researchers added.
For the study a total of 3,462 valid FITs were performed on patients aged 30 years and under who presented with non-alarm symptoms of colorectal cancer between 1 September 2015 and 30 August 2016. Of these, 540 (16%) were positive, resulting in urgent colonoscopy referrals. Three months after the initial FIT was performed as a rule-in, 9.4% (51) of patients were diagnosed with colorectal cancer - 67% of whom were in the early stages one or two of the cancer and 20% of whom were in the later stage four.
In addition, 13.5% (73) of those who received a positive FIT were diagnosed with some other serious bowel disease, and were treated accordingly.
The false negative rate for colorectal cancer was <0.1% for the initial three months after the FITS were first performed.
The researchers said awareness of false negative test results was important when using the test and further studies were needed to assess the exact performance of the FIT.
However they concluded: ‘Our results suggest that the FIT may be used as a rule-in test in this group of patients to detect both colorectal cancer and serious bowel disease in primary care, and that the stage distribution of detected colorectal cancer by this method may be more favourable.
‘We consider the findings of importance in a realistic diagnostic work-up of patients with non-alarm symptoms of colorectal cancer and it reveals a possible diagnostic supplement for a group of patients that are notoriously difficult to handle in primary care.’