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, although this will not be necessary in all cases. There are many variations in surgical technique.

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 chronic liver disease (malaise, weakness, jaundice, ascites, variceal bleed, encephalopathy) or with the anorexia and weight loss of an advanced cancer. The surgical treatment options include resection of the tumour and liver trans­plantation. Which option is most appropriate for an indi­vidual patient depends on the stage of their underlying liver disease, the size and site of the tumour, the availability of organ transplantation and the management of the immunosuppressed patient.

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 bladder (Fig. 52.28). Presentation is often with symptomatic gallstones where the gall-bladder cancer is an incidental finding. Alternatively, the patient may present with pain or obstructive jaundice and in these individuals the tumour is often advanced, having extended outside the liver or towards the hilum of the liver to produce ductal obstruction. Patients in whom the tumour is an incidental finding following cholecystectomy and is limited to the mucosa of the gall bladder have a good prognosis. Those in whom there is transmural spread or those presenting with obstructive jaundice have a poor prognosis. Staging of the tumour will decide the possibilities for management, and includes spiral CT scan of the chest and abdomen, cholangiography, selective hepatic angiography and staging laparoscopy. Radical surgery offers the only hope of cure for gall-bladder -cancer and this may involve removing the right lobe liver parenchyma, the biliary tree, along with the hilar lymphatic drainage of the gall bladder by a hilar lymphadenectomy. There is little evidence for chemotherapy either as a sole treatment or in an adjuvant setting. Patients presenting with obstructive jaundice due to an unresectable gall-bladder cancer may have the symptoms relieved by insertion of a biliary endoprosthesis.