Bowel cancer ‘red flags’ that can show two years before diagnosis

Bowel cancer is the fourth most common type of cancer in the UK

Researchers have identified four “red flag” bowel cancer symptoms that can show up to two years before diagnosis.

The symptoms could indicate greater risk of early-onset bowel cancer for people under 50 years old, researchers have found.

Bowel cancer is the fourth most common type of cancer in the UK, and the second most deadly, with 43,000 new cases every year.

The disease also causes almost 17,000 deaths a year and accounts for around 11% of all new cancer cases.

More than half of bowel cancer cases (54%) in the UK are thought to be preventable.

Researchers from the Washington University School of Medicine in St Louis believe the four symptoms could help with earlier detection and diagnosis among younger adults.

The four “red flag” symptoms, which patients are likely to experience between three months and two years before diagnoses, are:

• Abdominal pain
• Rectal bleeding
• Diarrhoea
• Iron deficiency anaemia

The researchers determined that having just one of the symptoms almost doubled the risk of bowel cancer, while those who had two symptoms were more than three and a half times at risk, and those with three or more symptoms were more than six and a half times at risk.

The study, which was published in the Journal of the National Cancer Institute, analysed data on more than 5,000 patients with early-onset bowel cancer.

Senior investigator Yin Cao explained: “Colorectal cancer is not simply a disease affecting older people; we want younger adults to be aware of and act on these potentially very telling signs and symptoms - particularly because people under 50 are considered to be at low risk, and they don’t receive routine colorectal cancer screening.

“It’s also crucial to spread awareness among primary care doctors, gastroenterologists and emergency medicine doctors. To date, many early-onset colorectal cancers are detected in emergency rooms, and there often are significant diagnostic delays with this cancer.”

Dr Cao also warned that patients with rectal bleeding and iron deficiency anaemia should have an endoscopy and follow-up.

First study author Cassandra Fritz said: “It usually takes about three months to get a diagnosis from the time a person first goes to the doctor with one or more of the red flag signs and symptoms we’ve identified. But in this analysis, we found that some young adults had symptoms for up to two years prior to their diagnoses.

“That may be part of the reason many of these younger patients had more advanced disease at the time of diagnosis than what we normally see in older people who get screened regularly.”

Bowel cancer screening is currently offered to people aged between 60 and 74 every two years in the UK, but screenings were expanded in 2021 to include people aged 50 to 59.

A study in March 2023 found that a new blood test could spare bowel cancer patients from undergoing unnecessary chemotherapy every year.

About 1,600 bowel cancer patients in the UK are set to take part in a study over four years.