Liver tumours
Surgical
approaches to resection of liver tumours
Adequate exposure of the liver is an absolute
prerequisite to safe liver surgery. A rooftop or transverse abdominal incision
provides excellent access to the liver if adequate retraction of the costal
margin is employed using a costal margin retractor. Thoracoabdominal incisions
are no longer required. The procedure for complete mobilisation of the liver is
described,
Mobilisation of the liver
The falciform ligament is first divided and
followed along the anterior surface of the liver towards the suprahepatic IVC.
The left triangular ligament is divided, facilitated by placing an abdominal
pack in front of the oesophagogastric junction. The right triangular ligament is
then divided by retraction of the diaphragm away from the right lobe parenchyma.
On exposure of the bare area of the liver the IVC can be seen as it
passes behind the liver and this can be slung above the renal veins below
the liver and at the level of the main hepatic veins. Mobilisation of the liver
is completed by division of the lesser omentum. Removing the liver from the IVC
is achieved by lifting the liver anteriorly to expose the multiple small veins
passing between the liver parenchyma and the IVC. These should be suture ligated
to ensure haemostasis. This proceeds from above the renal veins until the main
hepatic veins are reached below the diaphragm.
Dissection of the hilum
The peritoneum overlying the hilar triad is
divided. The common bile duct (CBD) is then exposed on the free edge of the
lesser omentum, mobilisation being facilitated by ligation and division of the
cystic duct and artery followed by removal of the gall bladder. Slinging the
CBD with an elastic sling allows exposure of the common hepatic artery and
dissection of the main right and left branches. These again may be slung to
allow the remaining lymphatic tissue surrounding the portal vein to be ligated
and divided. The possibility of an aberrant right hepatic artery should be
sought lying posterior to the bile duct and an accessory left hepatic artery
from the left gastric artery in the lesser omentum. Dissection of the hilar bile
ducts requires careful retraction on segment IV of the liver, and division of
the small vessels and bile duct branches passing between segment IV and the
confluence of the right and left hepatic ducts.
Division of the parenchyma
Once the liver has been adequately mobilised and the hilar vessels have been exposed the main inflow vessels and bile duct can be divided to the liver lobe to be resected. The arterial branch may be ligated but the bile duct should be transfixed with 4/0 PDS and the portal vein branch with 4/0 Prolene suture. Division of the inflow vessels produces a line of demarcation between the right and left liver passing to the right and parallel with the falciform ligament. The parenchyma is divided along this plane of demarcation commencing by diathermy of the liver capsule. The ultrasound (Cusa) dissector is the most common method used for division of the parenchyma. This allows the parenchyma to be divided leaving the vessels and bile duct branches to be diathermied or ligated depending
Hepatic adenoma (Fig.52.22)
These are rare benign liver tumours. Imaging by
CT demonstrates a well-circumscribed and vascular solid tumour. They usually
develop in an otherwise normal liver. Unfortunately, there are no characteristic
radiological features to differentiate these lesions from malignant tumours.
Angiography will demonstrate a well-developed peripheral arterialisation of the
tumour. Confirmation of the nature of these lesions is required by either
percutaneous biopsy or resection with histological confirmation. These tumours
are thought to have malignant potential and resection is therefore the treatment
of choice. Owing to their vascularity, bleeding following percutaneous biopsy
is well recognised. An association with sex hormones, including the oral
contraceptive pill, is well recognised and regression of symptomatic adenomas on
withdrawal of hormone stimulation is well documented.
Focal
nodular hyperplasia (FNH)
This is an unusual benign condition of unknown
aetiology in which there is a focal overgrowth of functioning liver tissue
supported by fibrous stroma. Patients are usually middle-aged females, and there
is no association with underlying liver disease. Ultrasound shows a solid tumour
mass but does not help in discrimination. Contrast CT may show central scarring
and evidence of a well-vascularised lesion. Again, these appearances are not
specific for FNH. A sulphur colloid liver scan may be useful. FNH contain both
hepatocytes and Kupffer cells. The latter takes up the colloid differentiating
FNH from either a benign adenoma or a primary or metastatic cancer, none of
which contains a significant number of Kupffer cells.
Surgery
for liver metastases
Outcome
The role of surgery in the treatment of
colorectal liver metastases is now well established based on prospective data
on resected patients compared with unresected patients with a similar stage of
disease. The role of resection of liver metastases from other primary sites
has not been defined. The expected patient survival rate for resection of
solitary colorectal metastases is approximately 35 per cent at 5 years
with few cancer-related deaths beyond this period. Multiple unilobar and bilobar
liver metastases may also be considered for resection, although cure rates are
significantly lower.
Staging
This involves defining the extent of the liver
involvement with metastases and excluding extrahepatic disease. A standard
work-up would involve oral and intravenous contrast CT scan of the liver and
abdomen, chest CT scan, bone scan and colonoscopy, to look for locally recurrent
or synchronous colonic cancers. This information should be taken in parallel
with a general medical evaluation before deciding on the suitability for surgery
of an individual patient. The typical appearance of colorectal liver metastases
on contrast CT is shown in Fig. 52.23. These patients usually have normal liver
parenchyma and therefore tolerate a 60—70 per cent resection of liver
parenchyma without showing evidence of liver failure.
Surgical
approach
The basic surgical approach for liver resection
is outlined above. A search for local recurrent disease, peritoneal deposits
and regional lymph node involvement should he made at the start of the
laparotomy. Planar imaging often overlooks peritoneal or superficial liver
metastatic deposits. Coeliac node involvement in patients with liver metastases
considerably reduces the overall survival whether or not the liver and nodal
disease is resected.
The
treatment of unresectable disease
These patients may be offered systemic
chemotherapy. First line treatment is with 5-fluorouracil and folinic acid,
which produces a response rate of 30 per cent and may improve the quality of
life. Other drug regimes are available and many studies are ongoing evaluating
hepatic arterial administration of chemotherapy or radioactive microspheres.
Many patients will have undergone previous adjuvant chemotherapy following
resection of the large bowel primary. There is no proof as yet regarding further
adjuvant treatment following resection of liver metastases.
Hepatocellular
carcinoma
Primary liver cancer (HCC) is one of the
world’s commonest cancers and its incidence is expected to rise rapidly over
the next decade. This rise is due to the association with chronic liver disease,
particularly HBV and HCV Owing to this association many patients who are known
to have chronic liver disease are now being screened for the development of HCC
by serial ultrasound scans of the liver or serum measurements of alpha
fetoprotein (AFP). Patients often present in middle age either because of
symptoms of the
Staging
and clinical assessment of hepatocellular carcinoma
In addition to a general assessment of the
patient’s fitness for surgery, crucial information is the severity of the
underlying liver disease based on Child’s classification (Table 52.5)
and
the size and site of the tumour. As chronic liver disease predisposes to these
turnouts they are often multifocal by the time of diagnosis. Extensive liver
resections in patients with advanced cirrhosis are associated with a high
mortality due to liver failure and sepsis. In contrast, extensive resections for
HCC in a noncirrhotic liver are associated with a low risk of liver failure, and
resection rather than transplantation would be the treatment option of choice.
Turnouts often metastasise to the lung and bone, and a chest CT scan and bone
scan are therefore useful staging investigations. Evidence of intraperitoneal
disease is difficult to determine by CT scan, and laparoscopy may be useful for
this purpose. The intrahepatic distribution of HCC is equally difficult to
determine within the cirrhotic liver. Ultrasound, early arterial phase enhanced
spiral CT scan and CT scan 2 weeks following intrahepatic administration of the
contrast agent Lipiodol are the most useful that are currently available (Fig.
52.24).
Surgical
approach to HCC
The surgical approach should remove the known
cancer with a 1—2 cm margin of unaffected liver tissue. In patients with
associated chronic liver disease the volume of liver resected should be
minimised to reduce the incidence of postoperative liver failure. Local or
segmental resections are preferred to major resections (Fig.
52.21).
Follow-up
and adjuvant treatment
There is little evidence that adjuvant
chemotherapy will improve the prognosis of patients following resection of HCC,
and it may damage the function of the liver in those with underlying chronic
liver disease. AFP is a clinically useful tumour marker for follow-up,
although its low sensitivity would suggest that imaging should also be employed.
Cholangiocarcinoma
Presentation,
pathology and natural history
Bile duct cancers typically present with
painless obstructive jaundice. Elderly patients are frequently affected, but
patients with primary sclerosing cholangitis (PSC) may develop these tumours at
a much earlier age. These rumours are typically slow growing and often arise at
the confluence of the right and left hepatic ducts, eventually invading the
liver parenchyma. Cancers at this site are usually fibrous and produce tight
duct strictures. Distal bile duct cholangiocarcinomas are more frequently
polypoidal and obstruct the lumen of the duct. Both invade perineural planes and
along lymphatics.
Investigation
and staging
The diagnosis should be suspected when
ultrasound examination of the jaundiced patient shows dilated intrahepatic but
not extrahepatic bile ducts.
Cholangiography
will usually show a hilar stricture (Fig. 52.25) and brush cytology will
provide a tissue diagnosis in about two-thirds of patients. Polypoidal turnouts
may closely mimic CBD stones (Fig. 52.26). Spiral CT scan often shows
little evidence of a mass lesion unless infiltration into the liver parenchyma
has occurred. Regional lymphadenopathy may be apparent but cannot be assumed to
be malignant. Evidence of local spread into the portal vein or evidence of
hepatic arterial involvement may be obtained by angiography. Distal spread at
presentation is unusual, as is peritoneal seeding. Hilar cholangiocarcinomas may
be categorised using the system suggested by Bismuth (Fig.
52.27).
Treatment
Surgical resection offers the only possibility
of cure and may also be the best form of palliation. Owing to local spread into
lymphatics and the perineural space, local resection of a hilar
cholangiocarcinoma is rarely curative, although some long-term survivors have
been reported. Radical resection of the liver parenchyma associated with the
affected bile duct has become the recognised treatment. Those patients in whom
the volume of residual liver parenchyma following resection may be inadequate
can be considered for transhepatic portal vein embolisation of the branch to the
side of the liver to be removed, as described by Nimura and colleagues. This
results in compensatory enlargement and functional improvement in the liver
parenchyma.
Gall-bladder
cancer
The aetiology of gall-bladder cancer is unknown
but it almost invariably is associated with the presence of stones in the
gall-bladder which may act as a chronic irritant to the gall bladder mucosa.
Evidence of a field change in the gall bladder mucosa with areas of dysplasia
would support this theory. It is also known to have a very high incidence in
patients with gall-bladder wall calcification, the porcelain gall