Hepatocellular carcinoma is a cancer that arises from liver cells. It is different to 'liver cancer' that has spread to the liver from elsewhere.
It is important that the lay reader does not confuse the term ‘liver cancer’, when referring to secondary cancer spreading to the liver, with primary cancer of the liver. In the Western world, the occurrence of metastatic cancer in the liver far exceeds the incidence of primary liver cancer and such problems in the liver are treated by the methods used to control the primary cancer. That is to say that if a patient has developed secondary breast cancer in the liver then it is treated with chemotherapy to which breast cancer is sensitive and not as a primary liver cancer would be.
Hepatocellular carcinoma is a true carcinoma but usually an aggressive one with a high mitotic rate (i.e. many cells capable of division at any one time). In the most commonly encountered form, the microscopist can recognise the attempts by the tumour cells to form the trabeculae that are characteristic of normal liver histology, the microtrabecular variant.
Two other forms, the sclerosing variant and the fibrolamellar variant are recognised, the latter tending to occur in younger patients and equally in males and females; it has a relatively better outlook.
Incidence of hepatocelluar carcinoma
In the Far East, Hepatocelluar carcinoma affects up to 1% of the population. In Europe the incidence is only 1 per 100,000 of people. In male Chinese carriers of the hepatitis B virus, there may be a lifetime risk of 50% of developing the disease, and exposure to the hepatitis virus and sometimes other infections (e.g. fungal aflatoxin – found in cereals stored in damp conditions) over a long period of time is unquestionably heavily related to an enhanced incidence of the disease. By contrast for the less common type of liver cancer, Cholangiocarcinoma (which is a cancer arising from the linings of the bile ducts), a chronic infection with the liver fluke (Clonorchis sinensis) predisposes to this cancer.
Symptoms of hepatocelluar carcinoma
Most patients who develop Hepatocellular carcinoma (HCC) have chronic liver disease. The tumour itself usually does not cause any further symptoms, and is detected by a scan and/or blood test. If it does cause symptoms, it is usually large and leads to a worsening of the liver.
Sometimes, patients have pain in the upper abdomen, weight loss, jaundice, or bleeding into the tumour or form dilated blood vessels at the top part of the stomach.
If the tumour has spread, there may be symptoms related to effects on the organ affected, for example bone pain.
Treatment of hepatocellular carcinoma
The ideal therapy for a localised hepatocellular carcinoma is an operation to remove the tumour completely. If the patient is fit, has a healthy liver and the tumour is not too large so as to leave behind enough liver to work well, then an operation should work well.
However, most patients with HCC have unhealthy livers and are not fit enough to go through major surgery.
Liver transplant has been used to treat some patients, but there are very strict criteria governing which patients are suitable.
If an operation is not possible or safe, then chemotherapy is considered. This is usually given intravenously but intra-arterial chemotherapy, when the chemotherapy is given into the blood vessel goes directly to the liver, has been used. This may give a higher dose of chemotherapy toe the tumour and can be combined with a procedure that blocks the artery leading to tumour. This has the effect of keeping the chemotherapy in the tumour for longer and at higher concentration. This is called 'trans arterial chemoembolisation' (TACE).
Single, smaller tumours may be treated with techniques such as 'radiofrequency ablation' (the use of a probe put directly into the tumour which heats the tumour up in a similar way to the way a microwave oven works). Other techniques that destroy the tumour in a targeted way are under development, including the CyberKnife which can give highly focussed radiotherapy very accurately.