The role of primary care
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 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.
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.
