Symud at y prif gynnwys

Bowel Cancer Awareness Month

April marks Bowel Cancer Awareness Month, an opportunity to shine the spotlight on this increasingly common and often devastating cancer.

Here at Cancer Research Wales, research into bowel cancer comprises a major part of our portfolio of projects. In this blog, we’ll look at some of the issues around bowel cancer in Wales and how our research is making a difference.

The Problem of Bowel Cancer in Wales

Bowel cancer (also known as colorectal cancer) is the fourth most common cancer in Wales with over 2500 cases diagnosed every year, accounting for about 1 in 8 cancer diagnoses. Of particular concern, more than half of these bowel cancer cases are diagnosed at Stage 3 or 4, meaning the disease is advanced and the patient’s prognosis is poorer.

One important reason for these late diagnoses is a lack of awareness of the symptoms of potential bowel cancer. Unfortunately, people may initially experience vague symptoms, such as unexplained weight loss or fatigue, and therefore delay going to their GP. For both these vague symptoms as well as the ‘red flag’ symptoms of bowel cancer (blood in your poo, persistent change in bowel habits or pain / a lump in your stomach area), it is really important to get checked by your GP.

Bowel cancer is the second biggest cancer killer in Wales, causing almost 1000 deaths each year. Awareness of symptoms and visiting the GP in a timely manner can play a huge role in reducing this number. However, there is also a lot of scope for improvements in the diagnosis and treatment of bowel cancer and that is where research can provide solutions.

Patients who have suspected bowel cancer will usually be asked to take a FIT (Faecal Immunochemical Test), which looks for traces of blood in the poo. This is the same test that is used for the bowel cancer screening program for people over 55. A positive result on the FIT does not necessarily mean that bowel cancer is present, but warrants further investigation – this is typically in the form of a colonoscopy.

There is a huge backlog of patients waiting for a colonoscopy in Wales, which was exacerbated by the Covid-19 pandemic. In fact, the current waiting list contains over 7000 people and of those over 3000 have been waiting more than 14 weeks, with some waiting 6 months or longer. Such delays will inevitably lead to cancers being diagnosed at a more advanced stage and so represent a major issue.

Better Bowel Cancer Diagnostics to Reduce the Backlog

Most patients referred for a colonoscopy will not have bowel cancer, so being able to distinguish these patients via other tests would help to cut the colonoscopy waiting list significantly. Cancer Research Wales has funded researchers at Swansea University who are developing a blood test that can detect bowel cancer or rule it out, without the need for a colonoscopy.

The Raman blood test analyses the ‘molecular fingerprint’ of substances in the blood, which changes when cancer develops, to be able to give patients results within a few days. In their early trials, the team found that their test detected 4 out of 5 early stage bowel cancers and 100% of later stage cancers, making it significantly more accurate than FIT.

Work is ongoing to further refine the Raman test and the team are also trialling whether their test is better than, or can provide added value to, the current FIT for bowel cancer screening. It is hoped that within the next few years, this innovative approach will be available to patients across Wales, who will benefit from earlier and more accurate bowel cancer diagnoses.

In cases where cancer is suspected, biopsy samples can be taken during the colonoscopy for microscopic analysis by trained consultants (called histopathologists). At present, there is a shortage of specialist histopathologists across Wales, meaning results can take weeks to be returned to the patient. With around a third of the current histopathology workforce approaching retirement age and years of training required to replace them, these delays are only likely to worsen in the coming years.

One promising method for speeding up cancer diagnoses from biopsy samples is the use of modern computing techniques, such as machine learning, to analyse microscopy images in order to support the work of histopathologists. Cancer Research Wales is funding a collaborative project between Swansea University and Betsi Cadwaladr University Health Board to develop such an approach to expedite bowel cancer diagnosis.

This project will design an automated pipeline for the analysis of potential bowel cancer samples. The machine learning-based approach will act as a triage tool, highlighting and annotating potentially cancerous areas on the images. In this way, samples can be analysed 24/7 by the automated process and the information fed to the histopathologists, who can then confirm a diagnosis. Such a system will allow each histopathologist to look at many more samples each day, reducing the delay for results from weeks to a few days and giving patients their diagnosis as soon as possible.

Preventing Bowel Cancer Recurrence

Treatment for primary bowel cancer typically involves surgery to remove the tumour, sometimes in combination with chemotherapy or radiotherapy. However, following surgery up to 1 in 4 patients will relapse within a few years and the prognosis for these patients is often poor. Cancer Research Wales is funding a major clinical trial that seeks to address this issue by using the patient’s own immune system to prevent relapses.

Research at Cardiff University, funded by Cancer Research Wales, previously demonstrated that low doses of a drug called cyclophosphamide could change the balance of the immune system, while having very few adverse side effects. The low dose of cyclophosphamide reduced the number of a type of cell called regulatory T cells – these cells function as the “brakes” of the immune system and can stop other immune cells from attacking a tumour.

The BiCCC (Brief Intervention with Cyclophosphamide in Colorectal Cancer) clinical trial will recruit 500 intermediate stage bowel cancer patients who have completed their treatment, to test whether relapse can be prevented using low doses of cyclophosphamide. By removing the “brakes” on the immune system, the team hope that any residual cancer cells left behind after the surgery can be killed, stopping the tumour from regrowing. By preventing relapses, this straightforward treatment could help to significantly reduce the number of bowel cancer deaths over the coming years.

Bowel cancer represents a major burden on the NHS in Wales and the number of cases diagnosed each year have steadily increased over the last 20 years. Addressing the challenges posed by this increasingly common cancer is a real priority and research can help to provide some of the answers.

Through our innovative research projects, Cancer Research Wales is giving clinicians the tools they need to detect and diagnose bowel cancer earlier and to ensure patients can be successfully treated first time. Thank you to all our supporters, without whom we would not be able to make such a difference.