Thursday August 20 2009
Excessive alcohol consumption increases the risk of liver cancer
Several newspapers reported today that cases of liver cancer have tripled. The Mirror article on liver cancer said that alcohol is to blame, as well as obesity and the blood infection hepatitis C. It reports that all three cause cirrhosis (scarring) of the liver, a condition that can develop into liver cancer. It said the “startling” figures from Cancer Research UK show that the number of cases of liver cancer has risen to 3,108 in 2006 from 865 in 1975.
What is the news based on?
These stories are based on the latest statistics published by Cancer Research UK about cancers starting in the liver (primary liver cancers) in 2006. The statistics look at how common the cancer is, how it has changed over time and how figures in the UK compare with those from other parts of the world. These statistics do not cover cancers that have spread to the liver from other parts of the body.
How have rates of liver cancer changed?
Primary liver cancer used to be rare in the UK. For example, in 1975 only 865 cases were reported in the UK. While these cancers are still uncommon, the number has grown substantially, and in 2006 3,108 cases were diagnosed. This is equivalent to an increase from about 1.4 people in 100,000 developing primary liver cancer in 1975 to about 3.9 people in 100,000 in 2006.
Liver cancer is the 18th most common cancer in the UK (based on 2006 figures), but is more common in other parts of the world. As there is a long delay between exposure to risk factors and the development of liver cancer, experts suggest that the number of new cases each year will continue to rise.
Primary liver cancer is more common in men than women (63% of new cases are in males). Rates increase sharply with age, and the highest rates occur in the oldest age groups. Most cases of liver cancer (about 70%) occur in people aged over 65 years. For those aged 85 and over the incidence rate per 100,000 men is 47, while for women it is 24.
Cancer Research UK has estimated that the lifetime risk of developing primary liver cancer is one in 180 for men and one in 292 for women in the UK.
What are the risk factors for primary liver cancer?
Risk factors for primary liver cancer include:
- Viral infections, such as hepatitis B or C.
- Excessive alcohol consumption.
- Being overweight.
Cancer Research says experts believe these three factors are the main contributing factors to the rise in cases of primary liver cancer in the UK. As these risk factors become more common, so does liver cancer.
Hepatitis and alcohol both cause cirrhosis, and this itself is a risk factor for primary liver cancer. The reasons for the link between being overweight and increased risk of primary liver cancer are unclear. It may be due to an increased risk of diabetes and of non-alcohol-related liver disease in overweight people.
Other causes of cirrhosis (including the inherited disease haemochromatosis and direct poisons such as aflatoxin, which is a contaminant found in some mouldy foods) can also increase risk of the cancer.
What is hepatitis C?
Hepatitis C is a virus. It spreads from person to person by blood-to-blood contact (for example through drug users sharing needles) and in rare cases it can be passed on by unprotected sex. Some of the increase in liver cancer seen may be due to use of hepatitis-C-contaminated blood products in the 1960s and 1980s. Since 1991 all blood products have been checked before use, so they are no longer a risk.
Some people who are infected with hepatitis C will clear the virus from their bodies, but many people develop mild to moderate liver damage, although they may not all experience symptoms. About a fifth of people who contract hepatitis C will eventually develop liver cirrhosis and some will develop liver cancer. Experts report that it can take 20 to 40 years between hepatitis C infection and onset of liver cancer. Therefore, even if new cases of infection were stopped, the number of cases of cancer would continue to rise for some years.
What are the symptoms of liver cancer?
Cancer Research reports that the symptoms of liver cancer include weight loss, a swollen tummy (abdomen), yellowish skin, dark coloured urine and pale coloured stools. Other symptoms include loss of appetite over a few weeks, being sick, feeling full or bloated after eating (even after a small meal), pain or discomfort in the abdomen, or a high temperature and sweating. In people with known chronic hepatitis or cirrhosis a sudden worsening of health could also indicate the possibility of liver cancer.
What can I do to reduce my risk of liver cancer?
Reducing your alcohol consumption and maintaining a healthy weight will help to reduce your risk of liver cancer, as well as offering other health benefits. In addition, people should avoid blood-to-blood contact, for example by avoiding sharing needles or unsafe sex. If you suspect that you may have hepatitis C seek medical attention, as there are treatments that can reduce the progression to cirrhosis. If you know that you have hepatitis C you should avoid drinking alcohol.