ABC of colorectal cancer: The role of primary care

Publisher Website
Google Scholar
Abstract
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. View larger version: In this window In a new window The NHS Executive's Referral Guidelines for Suspected Cancer 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. Symptoms associated with low risk of malignancy* Patients with the following symptoms but with no abdominal or rectal mass are at very low risk of colorectal cancer Rectal bleeding with anal symptoms (soreness, discomfort, itching, lumps, prolapse, pain) Change in bowel habit to less frequent defecation and harder stools Abdominal pain without clear evidence of intestinal obstruction * Adapted from Referral Guidelines for Suspected 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. In the absence of a family history of the disease, younger patients with a negative physical examination, including a digital rectal examination, can be initially treated symptomatically. If symptoms persist, however, patients should be considered for further investigation. Most (85-90%) colorectal cancers arise in people with no known risk factors, so opportunistic asymptomatic screening is of little value in colorectal cancer Patients with genetic predisposition All patients registering with a practice for the first time should provide details of their medical history. Patients with a history of familial adenomatous polyposis should be referred for DNA testing after the age of 15. Familial adenomatous polyposis accounts for about 1% of cases of colorectal cancer, with the defect gene identified on chromosome 5. Patients with a positive result should enter a programme of surveillance with flexible sigmoidoscopy. Patients with iron deficiency Patients aged 45 and over presenting with iron deficiency anaemia should be investigated to determine the cause of anaemia This will normally require both upper and lower bowel endoscopy In patients aged under 45, the cause of the anaemia should also be established, although the likelihood of this being colorectal cancer is low View larger version: In this window In a new window Haemoccult (SmithKline Beecham) has been the faecal occult blood test most often used in studies of the feasibility of screening for colorectal cancer The second common genetic predisposition to colorectal cancer is hereditary non-polyposis colon cancer. This condition should be suspected in patients describing three or more cases of colorectal cancer (or andenocarcinoma of the uterus) within their family. Such patients should be referred for endoscopic screening at the age of 25. Genetic testing for this condition is currently not feasible. In patients with a first degree relative with colorectal cancer aged under 45 or with two first degree relatives with the disease, the lifetime risk of the cancer rises to over 1 in 10. Such patients should be referred for lower endoscopy screening once they are 10 years younger than the age at which the disease was diagnosed in the youngest affected relative. An earlier article in this series gives more detail on the genetics of colorectal cancer. Further reading Carter S, Winslet M. Delay in the presentation of colorectal cancer: a review of causation. Int J Colorectal Dis 1998;13(1):27-31. Crossland A, Jones R. Rectal bleeding: prevalence and consultation behaviour. BMJ 1995;311:486-8. Curless R, French J, Williams G, James O. Comparison of gastro-intestinal symptoms in colorectal carcinoma patients and community control to the respect of age. Gut 1994;35:1267-70. Fijten GH, Starmans R, Muris JW, Schouten HJ,...

This publication has 0 references indexed in Scilit: