The symptoms of cancer of the large bowel may include any of the following:
blood in, or on, the stools (bowel motions) – the blood may be bright red or dark in colour
a change in your normal bowel habit (such as diarrhoea or constipation) for no obvious reason, lasting longer than six weeks
unexplained weight loss
pain in the tummy (abdomen) or back passage
a feeling of not having emptied your bowel properly after a bowel motion.
Sometimes tiredness (fatigue) is a symptom of a bowel cancer. This can happen if the bowel tumour has been bleeding and caused a shortage of red blood cells (anaemia). Anaemia may also make you feel breathless.
Sometimes the cancer can cause a blockage (obstruction) in the bowel. The symptoms of this are:
being sick (vomiting)
pain in the abdomen
a bloated feeling.
Although these symptoms can be caused by conditions other than cancer of the large bowel, it is important that you always have them checked by your doctor. As bowel cancer usually occurs in people over the age of 50, these symptoms in younger people are often thought to be due to other bowel problems, such as irritable bowel syndrome (IBS) or ulcerative colitis.
If you have symptoms that don’t improve within a few weeks, or if your symptoms are getting worse, it is important that you are referred to a specialist for tests to find out what the problem is.