Will new blood test for bowel cancer replace colonoscopy?

A new blood test for the early detection of bowel cancer bowel cancer is due to be launched. As Consultant Laparoscopic & Colorectal Surgeon, Mr Austin Obichere explains, the early detection is particularly critical in bowel cancer and so the test could significantly improve the chances of survival for thousands of patients.

Researchers at Swansea University led by Professors Dean Harris and Peter Dunstan, have developed the new technique using a detection method called Raman Spectrometry (RS).

Results from the study involving 27 practices and 595 patients across West Wales showed 79 per cent of early-stage bowel cancers and 100 per cent of advanced bowel cancers were identified. Comparison studies with other tests currently available in primary care have shown the RS blood test to have greater sensitivity for the detection of bowel cancer. 

Replacing need for painful and invasive colonoscopies

It is therefore hoped that the non-invasive test will cut waiting times for diagnosis and reduce the need for invasive procedures such as colonoscopies. Colonoscopy is not a pleasant experience for most patients and despite new "painless" methodologies, can be extremely painful.

Bowel cancer is currently the second leading cause of cancer death in Wales, with waiting times for diagnosis and treatment some of the longest in the developed world. Sadly, many of the 2,200 diagnosed cases in Wales each year are detected at an advanced stage, like Lynda, 66, from Swansea.

blood tests like this we can save many more lives

Lynda explains: “I was diagnosed with bowel cancer in June of 2021. I went to the GP with a small amount of blood in my stool and I was referred to the hospital for investigation. I didn’t have many symptoms. I am a very fit and active person, so I thought my weight loss was just down to being very physically active in the pool, gym, and on my bike. It came as a huge shock to me to find out I had 12cm of cancer in my bowel – and I needed immediate treatment to save my life.”

Lynda, who now has a stoma and is cancer free added: “I believe by introducing blood tests like this we can save many more lives in the future and prevent late diagnosis of bowel cancer in the majority of cases.”

Since the start of the pandemic, waiting lists for colonoscopies have significantly increased with just under 8,000 patients currently waiting to be screened. Half of these have waited longer than three months. These delays can reduce the chances of patient survival, with many people being diagnosed too late.

A Welsh diagnostic initiative

Speaking on their involvement in the project, Ann Tate, CEO Cancer Research Wales, said: “As a charity, investing heavily in research around cancer diagnosis is in our DNA. All cancer patients in Wales deserve innovative treatments for a better future and this test provides a solution for clinicians to diagnose cancer at an earlier stage. Our contribution was only possible due to the support of people across Wales, and for that we are extremely thankful.”

Commenting on Life Sciences Hub Wales’ role in securing the funding, Cari-Anne Quinn, CEO, said: “Earlier diagnosis and detection of cancer using less invasive methods is an essential part of the preventative agenda to make healthcare more efficient and improve patient outcomes. Life Sciences Hub Wales is delighted to be involved in this project through our funding support services and look forward to seeing its impact across Wales.”


A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
A common name for the large and/or small intestines. Full medical glossary
Abnormal, uncontrolled cell division resulting in a malignant tumour that may invade surrounding tissues or spread to distant parts of the body. Full medical glossary
The large intestine. Full medical glossary
Examination of the colon and rectum with a colonoscope, an imaging instrument that is inserted through the anus. Full medical glossary
The process of determining which condition a patient may have. Full medical glossary
The building blocks of the genes in almost all living organisms - spelt out in full as deoxyribonucleic acid. Full medical glossary
An abbreviation for epididymo-orchitis. Full medical glossary
Any test or technique that does not involve penetration of the skin. The term 'non-invasive' may also describe tumours that do not invade surrounding tissues. Full medical glossary
An outbreak of infection that affects numerous people in different countries. Full medical glossary
Relating to the rectum, the lowest part of the bowel leading to the anus. Full medical glossary
A way to identify people who may have a certain condition, among a group of people who may or may not seem to Full medical glossary