Symptoms of colorectal cancer

Bloody discharges from the rectum (rectal bleeding).

Abdominal pain. Which is less intense and with a more latent onset than in the acute presentation

Changes in bowel movement rhythm (whether it be diarrhoea or constipation)

Weight loss, loss of appetite (anorexia) and/or tiredness. The presentation of these symptoms could be signs of an advanced tumour

Anaemia. Colorectal cancer occasionally manifests as anaemia (iron deficiency anaemia) due to unnoticed blood loss through the digestive tract.

Intestinal perforation. This occurs when tumour growth affects the entire thickness of the intestine wall which eventually ruptures, subsequently allowing faecal matter to pass into the peritoneal cavity. This leads to acute peritonitis which manifests with abdominal pain and often fever.

Bowel obstruction. Similarly, tumours can grow until they obstruct intestinal transit, leading to abdominal pain and vomiting.