Generality
The liver is very often the site of tumors.
By far the most frequent are secondary ones - which originate in another location and give metastasis to the liver - but even primitive ones are not rare; the latter arise directly in the organ and their incidence is closely related to various risk factors that we will analyze later in the article.
Primary liver tumors: incidence causes tumor types symptoms diagnosis cure Secondary liver tumors
Primary tumors of the liver
They can be benign or malignant, with great prevalence of the latter, and can originate from various structures: hepatocytes (effector liver cells), bile ducts (which carry bile), connective liver or blood vessels.
Frequency of liver cancer
The disease has an incidence of around 5 cases per 100, 000 people in Western countries and even of 110 cases per 100, 000 in some South African countries, especially in Mozambique, where it is the most frequent tumor ever (due to the presence of many people infected by the virus of hepatitis B and hepatitis C). Italy is in an intermediate situation, with an incidence of around 20 cases per 100, 000 inhabitants.
Globally, liver cancer is the third leading cause of cancer-related death after lung and stomach cancer.
According to data released in 2014 by AIOM (Italian association of medical oncology), in Italy liver tumors:
- they represent 3% of all new cancer cases and are twice as frequent in males than females;
- unlike most neoplasms, this tumor has a higher incidence than the South;
- as observed for many other cancers, the cases in Italy are on the whole increasing due to the tendency to an aging population; excluding this aspect, the incidence of carcinoma appears to have decreased in the two sexes since the mid-1990s;
- are among the top 5 causes of death from cancer only in males (7%), among which are in fourth place (8%) in the age group 50-69 years.
- 17% of males and 16% of females who have contracted these neoplasms are still alive 5 years after diagnosis (2005-2007). Compared to the previous five years, life expectancy appears to be proportionally improved, even in the context of a disease, however, with a poor prognosis.
Figure: Number of deaths from liver cancer, standardized for age, per 100, 000 inhabitants. From wikipedia.org, Data related to 2004
Causes of liver cancer
Liver Cirrhosis
Hepatocellular carcinoma, especially in western countries, is frequently associated with hepatic cirrhosis, a disease characterized by an alteration of the normal anatomical structure of the liver, which then causes, over the years, its malfunctioning until death.
The direct damage to hepatocytes is often caused by the abuse of ethyl alcohol, which in turn, over time, gives rise to cirrhosis. This disease accelerates the proliferation of liver cells, called "regeneration", increasing the speed of DNA synthesis; during this process errors (aberrations) may occur that are responsible for the development of a hepatocellular carcinoma.
In the areas of Northern Italy about a third of liver tumors are attributable to the abuse of alcoholic beverages.
Viral Hepatitis
Another cause of liver cancer is related to hepatitis B and C viruses . It has been seen that where the number of carriers of viral hepatitis is high, the cases of liver tumors are equally high (a classic example are the regions of Africa where more than 10% of the population is positive for hepatitis). The hepatitis B virus predisposes to cancer because it is able to insert itself in the DNA of the hepatocytes, causing them to proliferate uncontrollably; that of hepatitis C does not integrate into the DNA, but also favors liver cancer with mechanisms that are still unknown.
On a national level, the role of hepatitis B as a cause of liver cancer is expected to decline following vaccination campaigns in those born from 1978 onwards.
hemochromatosis
Another disease of considerable importance is represented by hemochromatosis (which causes an enormous and pathological accumulation of iron in various organs, such as the liver, heart, brain, kidneys and pancreas).
Other Causes
Nitrosamines, which derive from nitrates present in various foods, but also some mycotoxins (produced by fungi that colonize peanuts and cereals) are certainly carcinogens. Of the latter, the most important is aflatoxin, a substance produced by a fungus, Aspergillus flavus, particularly common in certain tropical countries, such as Uganda; not by chance in these countries the contamination of food by aflatoxins is quite frequent (which is why the primitive carcinoma of the liver is widespread).
Also certain chemical substances, such as arsenic and vinyl chloride monomer (which is found in the plastic processing industry), can cause, with high frequency, a liver tumor called hepatic angiosarcoma, as well as it can cause a radioactive contrast medium called Torostat, which was used in the 1940s for angiography (radiographs of blood vessels), but which is no longer used today.
Other possible carcinogenic factors are represented by prolonged treatment with high dose anabolic steroid hormones, cigarette smoking and especially alcohol .
Some parasites such as Echinococcus granulosus, Schistosoma haematobium and Amoeba, can cause hepatic cysts, generally benign.
Oral contraceptives increase the risk of developing benign liver cancer very little.
The risk of liver cancer is also greater in the case of obesity (especially if complicated by the presence of diabetes), α-1-antitrypsin deficiency or in the case of non-alcoholic steatohepatitis (even in the absence of viral infection). Smoking has also recently been recognized as a risk factor.
