A team from the University of Dundee reviewed the medical reports of 777 patients with colorectal cancer from Tayside who had undergone surgery to remove affected bowel tissue.

The researchers identified how far advanced the cancer had become when medical treatment was first sought, and the socio-economic status of the patients.

They found that people of low socio-economic status were more likely to be present with the disease at an advanced stage.

The research was carried out at Ninewells Hospital

Colorectal cancer can be successfully treated in 90% of cases if it is diagnosed at an early stage. However, if allowed to develop to a more advanced stage it is more likely to kill.

The disease usually takes approximately a year to develop to its advanced stage.

Targeting needed

Dr Frank Carey, a pathologist who worked on the study, said the research highlighted the need to target screening programmes at the disadvantaged.

Two colorectal cancer screening pilots are set for launch, one in England, one in Scotland.

Dr Carey said: "We do not really know why there is a difference between the socio-economic groups, but it does seem that the message that blood in the stools should raise the alarm about cancer is not getting through to people who are more socially disadvantaged.