Carcinoma
of the pancreas
Pancreatic cancer is the eighth most common
cancer causing death in the UK. The incidence is 10 cases per 100 000 population
per year. The incidence has risen steadily over the last 25 years, until 5 years
ago when it levelled
off. The disease is a disease of ageing, with the average age of death
Pathology
More than 85 per cent of cases are duct cell
adenocarcinornas. The remaining tumours are a fascinating variety of
pathologies, each with their own characteristics. The more common tumours are
listed in Table 55.8. The importance of the pathology is that some
tumours have a prolonged natural history, for instance, the cystadenocarcinomas,
while those with an ampullary tumour (Fig. 55.32)
or a
neuroendocrine have an increased survival after resection.
Clinical
features
The most frequent symptoms are nonspecific,
namely epigastric discomfort, anorexia and weight loss. Often the patient is
aware of their digestion for the first time in their life, and such is the
mildness of the initial symptoms that they are frequently dismissed both by
patient and by doctor. Jaundice is the commonest sign and symptom which brings
the patient to the attention of his or her physician. Some 85 per cent of
patients present with this symptom. It is characteristically painless jaundice
but may be associated with nausea and epigastric discomfort. Change of bowel
habit is rare.
On
examination there is frequently evidence of weight loss, a palpable liver, a
palpable gall bladder and even metastatic lymph nodes in the neck. Courvoisier
first drew attention to the association of an enlarged gall bladder and a
pancreatic tumour in 1890, when he stated that when the common duct is
obstructed by a stone dilatation is rare; when the duct is obstructed in some
other way, dilatation is common. In those days dilatation of the duct could not
be determined and the dilatation, thus, refers to the gall bladder. Other signs
of intra abdominal malignancy should be looked for with care, such as a mass,
ascites and tumour deposits in the pelvis.
Investigation
If the patient is jaundiced, the usual blood
tests and ultrasound scan should be performed. This will determine whether or
not the bile duct is dilated. If it is and there is a genuine suspicion of a tumour in the head of the
pancreas, the preferred test is now a contrast enhanced spiral CT scan specific
for the pancreas. The next investigation is that of an endoscopic examination to
determine whether the jaundice can be relieved endoscopically. If it
can, a stent
should be inserted through the stricture to relieve the jaundice. Attention
should be paid to the coagulation to ensure that no bleeding occurs during this
process. If the ERCP shows the
characteristic features of a tumour and the CT scan shows that the tumour
is small (less than 4 cm), and confined to the head of the pancreas without
evidence of distant spread or
Management
At the time of presentation, 90—95 per
cent of patients are unsuitable for resection because of either local spread
into the superior mesenteric vein, para aortic or mesenteric lymphadenopathy,
or hepatic metastases. In some patients age precludes major operative
intervention. For those patients who are inoperable palliative treatment should
be offered.
The
role of chemotherapy in the management of pancreatic cancer remains ill
defined. If the tumour is a lymphoma then benefit is without doubt. Lymphomas
of the pancreas are rare, however, comprising less than 3 per cent of the total
number of pancreatic cancers. For the duct cell adenocarcinoma, 5-fluorouracil
(5FU) or gemcitabine will produce a remission in 15—25 per cent of patients,
whilst the remainder will have no benefit from the therapy. In those that have a
remission prognosis is extended by approximately 6 months. No long-term cures
have been described with oncological agents.
Surgical
resection
If a cystic tumour is encountered, no matter
how large, most of these can be removed surgically with a reasonable chance of
cure and with low operative mortality. Tumours of the ampulla have a good
prognosis and should, if at all possible, be resected. Some of the rare tumours
and the neuroendocrine lesions should also be resected if at all possible.
Patients with duct cell cancers which are less than 4 cm in diameter, not
involving the superior mesenteric or portal veins and with no evidence of
multiple enlarged nodes or distant spread, should be considered for a resection.
The appropriate resection is that of a pylorus-preserving pancreatoduodenectomy
with a local lymphadenectomy. Extended resections have not been shown to be
beneficial in improving survival and are associated with an increased morbidity.
The
operation can now be performed safely with a mortality of 3—5 per cent. The
morbidity remains high with some 40 per cent of patients developing a
complication in the postoperative period. These complications are usually infective,
but a leak from the pancreatic duct is known to occur in at least 10 per cent of
patients and this may give rise to major complications. The role of adjuvant
radiotherapy and chemotherapy with resection has not been elucidated.
Pancreatoduodenectomy
— preoperative
management. A full assessment of the patient’s general condition should be
carried out and a decision made whether or not to relieve the jaundice
preoperatively. Occasionally, if the period of jaundice is short (2 weeks), it
is safe to
proceed to operation, but if the period of jaundice is prolonged and a more
detailed preoperative assessment of operability is required then a stent allows
more time and relieves the symptoms associated with jaundice. The clotting
should be carefully checked preoperatively and adequate hydration ensured. A
full explanation is made to ensure that the patient is aware of the diagnosis,
the gravity of the operation and the risks involved, and consent taken.
Under
general anaesthesia with adequate monitoring, the abdomen is explored and
operability assessed. If the tumour is localised and without distant spread then
resection is appropriate. A cholecystectomy is performed. The bile duct is
dissected together with the structures in the porta hepatis, removing the
lymphatic tissue in this area. This will expose the hepatic artery and enable
division of the gastroduodenal artery which will expose the portal vein. The
duodenum and right colon are mobilised from the retroperitoneal tissues and the
fourth part of the duodenum is dissected and freed from the ligament of Treitz
so that the upper jejunum can be brought into the supracolic compartment. The
jejunum is divided and the mesentery of the proximal jejunum detached. The
proximal duodenum is divided. The neck of the pancreas is divided and then the
uncinate process separated from the superior mesenteric artery and vein working
up towards the upper bile duct which is divided releasing the specimen (Fig.
55.34). Retroperitoneal lymph nodes are completely removed with the specimen
as are those attached to the superior mesenteric vessels. Reconstruction is
carried out as in Fig.
The overall median survival for patients with
pancreatic cancer is 20 weeks. Less than 3 per cent of patients will survive for
5 years. Patients with a carcinoma of the ampulla of Vater who have had a
resection will have a 5-year survival rate of 40 per cent, while those with a
duct cell carcinoma will have a 5-year survival rate of 20 per cent. More
‘benign’ tumours will, of course, have a better prognosis. Following surgery
all patients who have had palliative treatment require regular follow-up in
order to care for steatorrhoea with enzyme supplementation, diabetes mellitus,
if it develops,
with oral hypoglycaemics or insulin as appropriate, and pain with either
analgesics or an appropriate nerve block. The procedure of transthoracic
splanchnicectomy is now the preferred procedure for relieving the pain and
should be considered in preference to a coeliac plexus block.