Incidence
Liver cancer is very common and can be considered as two types –
primary and secondary.
Secondary liver cancer
Occurs
when a cancer develops within some other organ such as the bowel, stomach,
pancreas or breast and then spreads to the liver.
The liver is the most common site of metastases (deposits of cancerous
cells distant from the primary source) from cancers originating in the
abdominal organs and approximately one third of these cancers ultimately
spread to the liver.
In Australia, most diagnosed cases of liver cancer are a result of
spread from other primary cancer sites.
Primary liver cancer (hepatocellular
carcinoma or HCC)
Cancer that arises from hepatocytes, the major cell type of the liver.
Worldwide, liver cancer is either the number one or number two cause
of cancer death. It is especially prevalent in parts of Asia, New Guinea,
the Pacific Islands and Africa. In those countries, more than 80% of
cases are due to chronic hepatitis B infection.
Until recently, HCC has been uncommon in Australia and other countries
with a predominantly European population.
Prior to the late 1980’s, most cases of liver cancer in Australia
were associated with alcoholic cirrhosis or haemochromatosis, but by
1990, hepatitis B and C were responsible for more than half the reported
cases of HCC. It is predicted that the incidence of HCC will continue
to rise, at least until 2020.
Causes of Liver Cancer
About 80% of people with HCC have cirrhosis.
A few liver cancers occur in an otherwise normal liver but these are
fairly rare and probably account for less than 10% of cases in Australia.
Some of the causes of cirrhosis and liver cancer are listed below.
1. Hepatitis B virus –
This is the most common cause of liver cancer worldwide. There is strong
evidence today that by treating the virus (and therefore the inflammation
caused by the virus) the chance of progressing to cirrhosis and liver
cancer should be reduced. This also applies to hepatitis C.
2. Hepatitis C virus –
second most common cause of liver cancer worldwide. As there are approx
15,000 new hepatitis C notifications per year in Australia alone and
considering the natural history of the virus, it is predicted that the
incidence of HCC will continue to rise.
3. Chronic excessive alcohol intake (alcoholic
liver disease) – an important causal factor on its own but
can add to the progression of Hepatitis B and C.
4. Aflatoxin – produced by a mould that is a contaminant of some
nuts, grains and beans.
5. Iron overload (usually genetic haemochromatosis)
Other Risk factors
• Age – average age for someone to develop HCC is mid 50s.
Very rare in those under 40 years of age.
• Sex – Liver cancer is 5 times more common in men than
in women.
• Country of birth – in the case of hepatitis B, people
are more likely to develop cirrhosis and HCC if the infection was
acquired
at a young age.
• Co-infection with another hepatitis virus or the HIV virus
in counties where infection at or around the time of birth is common,
HCC is more prevalent.
Diagnosis of Liver Cancer
Frequently, patients with liver tumours have no symptoms. Eventually
however, people will develop symptoms such as pain, abdominal fullness,
fever and/or jaundice.
Most hepatocellular carcinomas are first suspected based on the results
of CAT scans or ultrasound scans.
A blood test called “Alpha – fetoprotein” is a useful
marker for the diagnosis of HCC and about 70% of patients with liver
cancer have elevated blood alpha-fetoprotein levels. Although by no
means conclusive, a rising blood alpha-fetoprotein concentration (persistently
over 500ug/ml) in someone with chronic liver disease suggests the development
of HCC.
Can liver cancer be cured?
Treatment of secondary liver cancer varies with the underlying disease,
the extent of spread in the liver and other organs.
Some of the less common cancers such as testicular cancer involving
the liver can be cured with combination chemotherapy. Breast carcinoma
and lung cancer patients will often have a partial remission of the
cancer with chemotherapy. Bowel cancer may spread solely or mainly to
the liver, making treatment a viable option.
Surgery in some suitable cases of liver cancer can be curative. In
primary liver cancer, the cure rate for small cancers by surgery is
quite good (five year survival is more than 50%) but an ongoing problem
is the formation of new cancers in the highly diseased, cirrhotic liver.
Also, in advanced liver disease there can be many contraindications
to major surgery.
These considerations have led to increased interest in liver transplantation
to treat small liver cancers. However, there remains the difficulty
of finding sufficient numbers of organ donors.
Conventional chemotherapy has very little to offer someone with HCC.
Remissions are achieved in less than one-third of those treated and
are almost always of short duration (3-9 months), while the drugs that
can produce remission are very toxic.
Chemoembolisatiion
is a specialised type of chemotherapy delivered into the branch of the
hepatic artery that supplies the tumour. It represents another way to
achieve local control of liver tumours by limiting the spread of HCC
cells into the bloodstream. In general, chemoembolisation is reasonably
well tolerated.
Ablation therapy is a method of treating liver cancer using a variety
of techniques to shrink the tumour and slow the spread. At present,
in Australia the most promising
approach is RFA or radiofrequency ablation.
All local therapies can potentially remove smaller tumours or shrink
and temporarily control larger ones but there are limitations:
• Treatment may require several sessions
• Procedures performed through the skin can cause severe pain
• Formation of new tumours is almost inevitable within five years
Palliative care – alleviating symptoms
Unfortunately, only a small proportion of cases of liver cancer can
be cured. In the remaining cases, symptoms are likely to occur sooner
or later.
Pain is the most common symptom and is due to local invasion of the
liver capsule and neighbouring structures hat contain pain fibres.
The approach to pain control is similar to other cancers. Simple analgesics
should be used first, moving to opiates as indicated and using doses
and routes of administration that are appropriate to individual needs.
Fatigue, lethargy and weakness are the other common disabling symptoms
with liver cancer. Loss of appetite is also common and may be helped
by eating frequent, small carbohydrate-rich meals.
As well as the family doctor, the assistance of a pain clinic or palliative
care team linked to a community service is invaluable to provide the
best of care to someone with terminal liver cancer.
Acknowledgments: Hepatitis C, liver disorders and liver health –
Geoffrey Farrell
Hepatocellular Carcinoma – Howard J. Worman MD – Dept gastroenterology,
Columbia
