GPs can confidently avoid secondary care referrals for colorectal cancer investigation for patients who have had a negative result to a faecal immunochemical test (FIT), a study has concluded.
The new study, published in Alimentary Pharmacology & Therapeutics, concluded that a positive test of ten micrograms or more of haemoglobin per gram of sample detects 91% of underlying cancers.
Unlike colonoscopy, FIT tests are non-invasive and can be collected as a stool sample by the patient at home to be sent off for lab analysis.
They have been recommended by NICE since 2017 as a means to triage patients for urgent referral but GPs have expressed concern regarding false negatives, and still advise that GPs can refer patients following a negative FIT test.
A study into GP attitudes, published by BJGP in 2018, showed that only just over one-third of GPs across England would prefer to use a FIT to rule out colorectal cancer over referral to the 2WW pathway for a diagnostic colonoscopy.
But the University of Oxford researchers said their new study should give GPs confidence not to refer patients to secondary care following a negative FIT result, while advising them to reconsult it their symptoms persist or worsen.
And GPs in Oxford could now be told to only refer patients after a positive FIT test, after Oxford University Hospitals NHS Foundation Trust said it was currently in the process of redesigning its colorectal cancer pathway in light of the study.
As only one in ten people with colorectal cancer symptoms went on to receive a positive FIT result, this could save the NHS money and speed up investigations for those with cancer, according to the researchers.
They also said this could help prioritise the backlog of patients awaiting investigation for possible colorectal cancer symptoms due to the Covid-19 pandemic.
Researchers analysed the results of 14,487 FIT test requests for patients with symptoms that could be colorectal cancer. Patients were then followed up via their electronic patient health record for up to 36 months for evidence of colorectal disease.
The paper said: ‘A FIT threshold of ≥10 µg Hb/g faeces would be appropriate to triage adult patients presenting to primary care with symptoms of serious colorectal disease. FIT may be used to reprioritise patients referred with colorectal cancer symptoms whose investigations have been delayed by the Covid‐19 pandemic.’
Lead researcher Dr Brian Nicholson, a GP in Oxford, said: ‘This study will give GPs the confidence to request a FIT test for patients with symptoms of colorectal cancer. FIT provides a non-invasive simple home-based test that supports urgent referral for colorectal cancer investigation if positive.
‘If negative, the risk of cancer is similar to somebody without symptoms and immediate referral can be avoided, but patients should be given safety netting advice to reconsult if their symptoms are persistent or worsening.’
Professor James East, consultant gastroenterologist at Oxford University Hospitals NHS Foundation Trust, said: ‘The simple at-home kit could be used to reduce pressure on urgent NHS referral pathways by identifying patients who do not require further investigation for colorectal cancer, thereby controlling colonoscopy demand and reducing costs.
‘FIT could also be used to reprioritise patients with colorectal cancer symptoms whose tests have been delayed by the Covid-19 pandemic, helping us avoid delayed cancer diagnosis due to the backlog.’
‘A positive FIT test from a patient tested in primary care for suspected colorectal cancer or serious colorectal disease should prompt urgent referral for definitive colorectal investigation.’
But Dr Richard Roope, Cancer Research UK’s senior clinical advisor, said GPs should still use the rapid referral pathway based on symptoms even if patients’ FIT test came back negative.
He told Pulse: ‘This important piece of research shows how a simple test undertaken by patients at home will help hospital teams prioritise those who have symptoms that may be caused by colorectal cancer. It can also be used to assess patients whose symptoms do not otherwise reach the referral threshold.
‘However, GPs should still be referring people who have symptoms that feature in the rapid referral guidance (NICE Guidance NG12 in England) via the cancer rapid referral pathway (2 week wait referral pathway in England) regardless of the results of their FIT test.’
A spokesperson for NICE said: ‘This research backs up our diagnostics guidance recommendations for quantitative faecal immunochemical tests to guide referral for colorectal cancer in primary care published in July 2017. NICE carries out a literature search to identify any new evidence three years after diagnostics guidance has published, so this new study will inform whether we update our guidance when the search for new evidence takes place in the near future.
‘Due to delays caused by the COVID-19 pandemic, this update has yet to be scheduled in our work programme.’
GPs in London were already blocked from referring patients with urgent suspected bowel cancer to hospitals without a positive FIT test under changes to local NHS guidance due to the Covid pandemic. At the time, cancer experts warned that while useful, FIT tests do not pick up all cancers.
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05 February 2024