Precision medicine in gastroenterology

Taking an individualised approach to screening, treating and monitoring patients was the focus of a dedicated session on precision medicine in gastroenterology during the Irish Society of Gastroenterology Summer Meeting 2023, which took place at the Grand Hotel, Malahide, Co Dublin, on 22-23 June.

Dr Craig Mowat, Clinical Senior Lecturer and Honorary Consultant in Gastroenterology, School of Medicine, University of Dundee, Scotland, discussed personalised colorectal cancer screening and post-polypectomy surveillance.

He highlighted the importance of measuring faecal haemoglobin concentrations to predict the risk of underlying pathology through the faecal immunochemical test (FIT). However, Dr Mowat stressed that the current ‘one-size-fits-all’ approach taken in screening programmes simply does not work, as there are clear inequalities in FIT uptake among certain populations eligible for colorectal cancer screening.

While women are better in general at taking up screening invitations, the yield of neoplastic pathology and FIT positivity is lower in women.

Dr Mowat pointed out they have lower faecal haemoglobin concentrations than men so the current guideline thresholds may not be appropriate for them; they are more likely to have an incomplete colonoscopy; and the data shows that the majority of interval cancers are diagnosed in women.

He also discussed the growing evidence that FIT should be extended to primary care to triage patients for colonoscopy, citing the Scottish experience. A positive FIT test is a very effective screening tool and reduces unnecessary colonoscopy referral rates as well as identifying those in need of a more urgent colonoscopy, meaning lower waiting times for those who are more likely to need the procedure. “It is established now in national bowel screening programmes and there is lots of strong evidence and indeed guidance now that we should be extending this into primary care to give our patients the best chance of coming forward for colonoscopy in a timely fashion when resources are limited,” he told the Medical Independent (MI).

Dr Mowat acknowledged that GPs are already very busy and do not appreciate having more work ‘dumped’ on them without consultation. “However, when we introduced this in Dundee, it only took a few cases of giving them feedback of cases of patients deemed at low risk on routine colonoscopy waiting lists who handed in FIT test results, which saw them fast-tracked for colonoscopy where they were subsequently diagnosed with a cancer, for them to realise that actually this was a good test to have in primary care and they should be doing it, and that was what swung GP opinion around,” he told MI.

Also speaking during this session, Prof Guruprasad Aithal, Deputy Director and Theme Lead, National Institute for Health and Care Research, Nottingham Biomedical Research Centre, UK, discussed precision medicine in hepatology from guideline-specific therapy to personalised patient care (in cirrhosis). “With stratified medicine, it is geared towards the biological features of the individual to identify the best treatment,” he said, compared to traditional care which focuses on specific groups of patients. Personalised care also means patients have choice and control over the way their care is planned and delivered, Prof Aithal said.

Looking at cirrhosis, he discussed strategies for earlier diagnosis and the current British guidelines. Seeking out and treating portal hypertension in high-risk individuals is key, Prof Aithal said. He advised using MRI as a screening modality to identify the window and pre-emptive pharmacogenomics. Non-selective beta-blockers (NSBBs) remain the mainstay of treatment for portal hypertension, Prof Aithal said. As per the British Society of Gastroenterology guidelines, refractory ascites should not be considered as a contraindication to NSBB use, but these patents should be monitored closely and dose reduction or discontinuation may be appropriate in those that develop hypotension or acute/progressive renal dysfunction.

He also discussed the importance of pre-empting and preventing adverse drug reactions, and monitoring for development of hepatocellular carcinoma, again using MRI, with machine learning now refining and improving detection rates.

Speaking on the topic of precision medicine in inflammatory bowel disease (IBD) during this session, Prof Joana Torres, Consultant Gastroenterologist, Hospital Beatriz Angelo, Loures, Portugal, said that biomarker development needs to be embedded in clinical trial design, and it needs to be accepted that treatments do not work the same in all patient populations. “The availability of multiomics data and computational proficiency will continue to grow exponentially over the coming years, extending the boundaries of what is achievable for IBD precision medicine,” she summarised. 

However, in the meantime, before all these tools become widely available, Prof Torres said there is a lot that can be done to improve patient outcomes including focusing on earlier intervention, risk-stratifying, and using treat-to-target approaches with standardised monitoring and follow-up.