Early diagnosis and referral guidelines Early diagnosis of colorectal cancer is essential in view of the
stage related prognosis. Three potential levels of delay occur in the diagnosis of the disease: delay by the patient in presenting
to the general practitioner; delay in referral by the general practitioner to a specialist; and delay by the hospital in either
establishing the diagnosis or starting treatment. Detrimental differences between England and Wales and the rest of western
Europe in survival rates for colorectal cancer arise primarily in the first six months after diagnosis, suggesting that these
differences relate to late presentations or delays in treatment. 

Patients presenting with symptoms 
Most patients developing colorectal cancer will eventually present with symptoms. Primary symptoms include rectal
bleeding persistently without anal symptoms and change in bowel habit—most commonly, increased frequency or looser
stools (or both)—persistently over six weeks. Secondary effects include severe iron deficiency anaemia and clear signs of
intestinal obstruction. Clinical examination may show a definite right sided abdominal mass or definite rectal mass.
Unfortunately, many large bowel symptoms are common and non-specific and often present late. Recently published
guidelines, however, make specific recommendations about which patients should be urgently referred—within two
weeks—for further investigation in the NHS. The guidelines also indicate which symptoms are highly unlikely to be caused by
colorectal cancer. 

The risk of colorectal cancer in young people is low (99% occurs in people aged over 40 years and 85% in those aged
over 60). In patients aged under 45, therefore, initial management will depend on whether they have a family history
of colorectal cancer—namely, a first degree relative (brother, sister, parent, or child) with colorectal cancer presenting below
the age of 55, or two or more affected second degree relatives. Patients aged under 45 presenting with alarm symptoms and a
family history of the disease should also be urgently referred for further investigation.

In patients suspected of having colorectal cancer, referral should be indicated as urgent (with an appointment expected
within two weeks); the referral letter should include any relevant family history and details about symptoms and risk factors. An
increasing number of general practitioners will have direct access to investigations, often via a rapid access rectal bleeding
clinic. The usual investigations needed will be flexible colonoscopy or barium enema studies.