Hepatocellular carcinoma (HCC) is common in Oriental countries. It is one of the most malignant tumours, and carries a poor prognosis without treatment because of a high incidence of associated liver cirrhosis and its propensity to invade the portal or hepatic veins and to spread rapidly to the entire liver. Most of hepatocellular carcinomas in the East develop on a substate of underlying cirrhosis caused by hepatitis virus.

Although the resectability of the tumour is low because of this high incidence of associated cirrhosis and late diagnosis, the routine use of serum &agr;-fetoprotein estimation and ultrasonography in patients with chronic liver disease has increased the rate with which tumours smaller than 5 cm in diameter are detected. Most physicians recommend monthly estimation of serum &agr;-fetoprotein and an imaging study every 3 months for patients with chronic liver disease.

A sharp, steady rise in serum &agr;-fetoprotein is highly diagnostic for hepatocellular carcinoma. However, it is noteworthy that serum &agr;-fetoprotein is normal in 43 per cent of patients with tumours smaller than 3 cm in diameter. Ultrasonography is extremely useful to cover the weakness of &agr;-fetoprotein measurements. Small hepatocellular carcinomas are usually hypoechoic, but may be hyperechoic if the tumour contains fat. The weak point of this method is that lesions in the right hepatic dome are often missed because of its blind angle. Another problem is that the ultrasonographic probes currently available can rarely detect lesions smaller than 1 cm in diameter.

Angiography is more sensitive for the detection of minute hepatocellular carcinomas, as they are usually hypervascular even if they are tiny. However, tumours in segments II and III (Couinaud classification) can occasionally be missed even by superselective arteriography. Computed tomography (CT) without contrast media is not so effective in detecting small tumours developing in cirrhotic livers, although enhanced CT has a higher detection rate. Magnetic resonance imaging of the liver is accurate only when the tumour is more than 2 cm in diameter, when the detection rate is 97.5 per cent compared to 33.3 per cent for tumours less than 2 cm in diameter.

The most important approach for the early detection of minute hepatocellular carcinomas is to combine two or three of the methods described above.

Recent advances in diagnostic methods have increased the chances of detecting asymptomatic tumours of the liver. However, qualitative differentiation of space-occupying lesions is not necessarily easy, particularly when the lesions are small. One of the lesions which needs to be differentiated from hepatocellular carcinoma is adenomatous hyperplastic nodule in the cirrhotic liver. This occasionally contains tiny nodules of hepatocellular carcinomas within it, or both conditions may develop synchronously or metachronously in the same cirrhotic liver. Although this lesion is usually discovered by ultrasonography its sonographic features are similar to those of hepatocellular carcinoma. CT is usually negative but may show the presence of a low-density lesion if fatty change is prominent; angiography is usually negative. Another lesion to be differentiated from hepatocellular carcinoma is haemangioma. Small haemangiomas are hyperechoic on ultrasonography and may or may not be depicted by angiography. Ultrasound- or CT-guided needle biopsy is necessary to obtain a definitive diagnosis.

Early detection of small hepatocellular carcinomas makes resection possible, even in the presence of liver cirrhosis, because such small tumours can be removed by a minor hepatic resection. In a series of 22 cirrhotic patients with hepatocellular carcinoma smaller than 3 cm in diameter, the 3-year survival rate was only 12.8 per cent without anticancer treatment. Higher survival rates are obtainable by partial wedge or segmental resection.

Limited resection of the cirrhotic liver with minute hepatocellular carcinomas can be safely undertaken using intraoperative ultrasonography: this will reveal the many small tumours embedded in the liver parenchyma which are both invisible and impalpable during surgery.

Resection of the cirrhotic liver is technically demanding because portal hypertension and coagulation disorders are usually present to some degree in those with liver cirrhosis. The Pringle manoeuvre (compression of the portal triad), with or without temporary occlusion of the hepatic vein trunk, is useful to prevent severe haemorrhage and to reduce postoperative morbidity and mortality. The operative mortality rate is usually below 5 per cent after limited resection of the cirrhotic liver. The long-term survival rate is 30 to 50 per cent.

It is not known whether liver transplantation produces a better result than conventional resection in the treatment of hepatocellular carcinoma in the Orient. However, the results from Cambridge, Hanover, and Pittsburgh indicate a possibility that many patients benefit more from liver transplantation than hepatic resection because preclinical small tumours with advanced cirrhosis seem to represent a more favourable indication for transplantation.

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