Colorectal cancer in young people: Watch out for red flags

Who thinks instantly of bowel cancer when abdominal pain or diarrhoea hits? It turns out, these complaints may be key symptoms of early colorectal cancer.

What is early-onset colorectal cancer (EOCRC)?

Why is early detection of EOCRC so important?

The figures are alarming. More people are developing colorectal cancer at a young age. In the USA, an annual increase of 2% has been recorded in recent years, which could more than double by 2030. The incidence of EOCRC has also increased significantly in Germany.

However, the current screening programme for the early detection of colorectal cancer does not reach these young patients. This makes it all the more important to look out for corresponding symptoms in order to detect those affected in good time.

A recent population-based case-control study investigated what these symptoms could be. A large database of US policyholders was used to search for signs and symptoms that occurred particularly frequently before a later cancer diagnosis. The researchers focussed on a period of two years to three months prior to diagnosis.

Which symptoms indicate colorectal cancer?

The average age of the 5,075 younger patients with colorectal cancer was 43 years. Most (63%) were diagnosed with colorectal cancer. Before diagnosis, the following four symptoms were reported frequently:

  1. Abdominal pain
  2. Rectal bleeding
  3. Diarrhoea
  4. Iron deficiency anaemia

Almost 1/5 of those affected had one or more of these clinically significant symptoms before the diagnosis date. Abdominal pain was the most common. However, the risk of early colorectal cancer was highest for rectal bleeding, followed by iron deficiency anaemia, and diarrhoea. The more symptoms occurred at the same time, the greater the risk. Those suffering from three of the symptoms had a 6.5-fold increased risk of being diagnosed with cancer at a later stage. The associations were all the more pronounced the younger the patients were.

How long does it take from symptom to diagnosis?

The diagnosis intervals were particularly long for patients with only one of the four symptoms. Those who only complained of non-specific abdominal pain had to wait an average of almost a year for the correct diagnosis. Rectal haemorrhage was the fastest at 7 months, still a long time. And even in cases with three or more clear signs, it took an average of 5 months to reach a diagnosis.

According to the study authors, it is therefore important to raise awareness of early warning signs of bowel cancer at a young age. The earlier the tumour is detected, the more promising the treatment and prognosis.

Key take away for medical practice

In light of the increasing number of colorectal cancers before the age of 50, and the gap in screening programs for this target group, physicians must be all the more vigilant in detecting clinical signs of colorectal cancer at an early stage. Rectal bleeding and/or iron deficiency anaemia, in particular, should raise the alarm and prompt prompt diagnostic clarification.

  1. Fritz C et al. Red-flag signs and symptoms for earlier diagnosis of early-onset colorectal cancer, JNCI: Journal of the National Cancer Institute, Volume 115, Issue 8, August 2023, Pages 909–916,