Bowel
obstruction, often recurrent, is a common complication of
advanced colorectal cancers. The obstruction may occur at
several levels.
Continuous abdominal pain caused by the presence of the
tumour occurs in about 90% of cases, and intermittent colic
is present 75% of the time. Abdominal distension is variable,
as is nausea and vomiting. There may also be constipation
and/or diarrhoea.
Surgery
may not always be appropriate for patients with bowel obstruction
by a cancer. Contraindications include a recent “open
and close” laparotomy, diffuse intra-abdominal carcinomatosis
(whether palpable or demonstrated radiologically), severe
problems with gut motility, and massive ascites that rapidly
recurs after drainage. Many of these patients have extra-abdominal
metastases, poor performance status, and/or cachexia, which
complicate surgery.
Self-expanding
metallic stents have increasingly been used in the management
of obstructions in the gastric outlet, proximal small bowel,
and colon, and may be useful in those patients not suitable
for surgery. Contraindications include the presence of multiple
sites of stenoses, and complications include perforation,
bleeding, and stent migration.
The
pharmacological or medical management of cancer patients
with a blocked bowel focuses on relief of nausea, vomiting,
and pain. A combination of anti-emetics, anti-secretory,
and analgesic agents may be required.
It may
not be possible to stop vomiting completely in cases of
severe obstruction, but it can be reduced to an acceptable
level of once or twice a day. Metoclopramide is the drug
of choice in patients with mainly functional bowel obstruction,
but may worsen colic or vomiting in complete or severe mechanical
obstruction. Other anti-emetics used come from the butyrophenone
(eg, haloperidol, Haldol), antihistamine, and phenothiazine
groups.
Pain
is treated with analgesics, including morphine, and colic
(painful peristalsis) with hyoscine butylbromide (Buscopan).
Hyoscine butylbromide also has anti-secretory activity.
A trial of corticosteroids may be started to see whether
these agents offer relief.
Most
of the drugs mentioned can be mixed and given as a subcutaneous
infusion with a syringe driver if the oral route is not
feasible. The subcutaneous route of infusion enables patients
to move about freely and to be cared for at home. Patients
can eat and drink as they can tolerate; small frequent,
low-residue snacks or meals are recommended.
NOREEN
CHAN
Consultant
Palliative Medicine
Ref.
: Ripamonti C, Twycross R, Banes M et al. Clinical practice
recommendations for the management of bowel obstruction
in patients with end-stage cancer. Supportive Cancer Care
(2001) 9: 23-233
