Liver cancer
Globally, , liver cancer resulted in 754,000 deaths, up from 460,000 in 1990, making it the third leading cause of cancer death after lung and stomach. In 2012, it represented 7% of cancer diagnoses in men, the 5th most diagnosed cancer that year. Of these deaths 340,000 were secondary to hepatitis B, 196,000 were secondary to hepatitis C, and 150,000 were secondary to alcohol. HCC, the most common form of liver cancer, shows a striking geographical distribution. China has 50% of HCC cases globally, and more than 80% of total cases occur in sub-Saharan Africa or in East-Asia due to hepatitis B virus. Cholangiocarcinoma also has a significant geographical distribution, with Thailand showing the highest rates worldwide due to the presence of liver fluke.
Liver support systems
In hyperacute and acute liver failure the clinical picture develops rapidly with progressive encephalopathy and multiorgan dysfunction such as hyperdynamic circulation, coagulopathy, acute renal and respiratory insufficiency, severe metabolic alterations and cerebral edema that can lead to brain death. In these cases the mortality without liver transplantation (LTx) ranges between 40-80%. LTx is the only effective treatment for these patients although it requires a precise indication and timing to achieve good results. Nevertheless, due to the scarcity of organs to carry out liver transplantations, it is estimated that one third of patients with ALF die while waiting to be transplanted.
On the other hand, a patient with a chronic hepatic disease can suffer an acute decompensation of liver function following a precipitating event such as variceal bleeding, sepsis and excessive alcohol intake among others that can lead to a condition referred to as acute-on-chronic liver failure (ACLF).
Both types of hepatic insufficiency, ALF and ACLF, can potentially be reversible and liver functionality can return to a level similar to that prior to the insult or precipitating event.
LTx is the only treatment that has shown an improvement in the prognosis and survival with most severe cases of ALF. Nevertheless, cost and donor scarcity have prompted researchers to look for new supportive treatments that can act as “bridge” to the transplant procedure. By stabilizing the patient’s clinical state, or by creating the right conditions that could allow the recovery of native liver functions, both detoxification and synthesis can improve, after an episode of ALF or ACLF.
Basically, three different types of supportive therapies have been developed: bio-artificial, artificial and hybrid liver support systems (Table 2).