F D Richard Hobbs

Every general practitioner in the United Kingdom will on average see one new case of colorectal cancer each year. For most primary care doctors the most important contributions they make to the care of patients with colorectal cancer relate to early diagnosis of the condition (including the point of referral) and to palliation of symptoms in those with established disease. Further roles in the future primary care service are screening for colorectal cancer (possibly using faecal occult blood testing) and a greater involvement in monitoring patients after curative procedures.

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.

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.

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.

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 adenocarcinoma 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.

Population screening in primary care

The United Kingdom currently has no national screening programme for colorectal cancer. Several studies in the United States and Europe have shown that screening with faecal occult blood testing will reduce the overall mortality of colorectal cancer by about 15%. Such testing is a fairly simple procedure: only two small samples from different sites of a stool need to be collected on each of three consecutive days. In the United States, the specimens are then normally hydrated, whereas research in the United Kingdom and Denmark advocates using dry samples. The latter technique results in a lower sensitivity, but higher specificity - desirable test performance characteristics for an asymptomatic population screening procedure. Faecal occult blood testing is therefore a cheap and easy method of screening, with reasonable levels of acceptability to the population. The main disadvantages of this test are the low sensitivity - with about 40% of cancers missed by a single screen, leading to the need for frequent faecal occult blood tests - and the fact that bleeding tends to occur late in the development of the disease. Furthermore there are no direct studies to guide on the most cost effective method of establishing a national screening programme using faecal occult blood testing. However, evidence from the cervical screening programme suggests that general practice led "call/recall" programmes would have the greatest impact.

A large Medical Research Council trial is currently evaluating once.only flexible sigmoidoscopy as a method of screening patients aged 50.60 years. The results of this trial will not be available for several years.

The American Cancer Society recommends an annual digital rectal examination for people aged over 40, an annual faecal occult blood test for people aged over 50, and flexible sigmoidoscopy every three to five years for people aged over 50. More detail on screening for colorectal cancer appears in an earlier article in this series.

Managing patients with established disease

After confirmation of diagnosis, the role of the primary care doctor revolves around advice, support, possibly monitoring for recurrence, and palliative care. Some general practices are involved with home based chemotherapy, usually coordinated by specialist outreach nurses.

In the United Kingdom primary care does not currently have a formal role in monitoring for disease recurrence after curative treatments. Data on this option are limited (see a later article in this series) but suggest that such surveillance could be safely conducted in primary care. Ideally, this monitoring should be accompanied by adequate infrastructure and training in primary care, with good liaison between the practice and secondary (or tertiary) care.

Limited evidence from other types of shared care indicate that certain factors are likely to improve outcomes: structured and planned discharge policies; the use of shared (preferably patient held) cards that document patient information (disease progress and drug treatments, as a minimum); locally agreed guidelines specifying the appropriate follow up and delineating responsibilities; and access to rapid referral clinics. As with follow up in all chronic diseases, the more communication between doctors and with the patients (and their families), the better the quality of care.

Where appropriate, the doctor should also counsel patients on any possible familial risk and the need for genetic counselling of relatives. The primary care doctor may also advise patients with diagnosed colorectal cancer about practical considerations, including access to social security benefits. In the United Kingdom eligibility for attendance allowance may be immediately available in the exceptional circumstance of cancer with a short terminal prognosis of less than six months. For some patients, especially those with rectal tumours, the diagnosis of cancer is also accompanied by the necessity for either colostomy or ileostomy. Such patients will often require further specialised support, and liaison between the primary care team and specialist stoma nurses is important. As the disease progresses, management will shift towards palliative care. Ideally, this would be delivered jointly by the primary care team and specialist palliative care services, such as those based at a hospice or provided by Macmillan nurses. Few data exist to guide on the most effective models for palliative care in colorectal cancer. However, non.randomised studies have shown high satisfaction among patients when they are kept fully involved in understanding the progression of their disease and their treatment options, when shared care cards are used, and when home care teams are provided.

The main priorities in palliative care in colorectal cancer include the management of pain, jaundice, ascites, constipation, and nausea. The importance of attempting to correct these symptoms cannot be overstated: as much distress may be caused by constipation or nausea as by pain. Full explanations of signs such as jaundice are likely to be reassuring. Moreover, the advent of specialist home care teams (with access to specialist equipment-such as bed aids to preserve pressure areas or syringe drivers for pain control) and skilled counsellors for patients and their families, enables virtually all patients who wish it to remain at home.

Such an option is further enhanced by relief admission - when necessary for the patient or the family - to specialist palliative care wards or, more likely, to a hospice. In the United Kingdom only a minority of patients with colorectal cancer currently die from their disease in hospital or in a hospice.

The photograph of the Macmillan nurses is published with permission from Macmillan Cancer Relief.