The liver is a critical organ in our body that supports metabolism, assists in digestion and synthesises various components for our body’s immune system and blood clotting factors. It also aids in detoxification of certain chemicals from our body.
1. What is the Prevalence of Liver Cancer (Hepatocellular Carcinoma)?
Cancers in the liver can be divided into primary liver cancers or more commonly, spread from other primary sites of cancer such as breast, lung or colorectal cancers. According to the World Health Organisation, hepatocellular carcinoma (HCC) is the 5th most common cancer in men and 9th most common cancer in women worldwide. It is the 2nd most common cause of cancer-related death.1 HCC accounts for about 80% of primary liver cancers. The incidence is highest in eastern and south-eastern Asia and lowest in northern Europe. In Singapore, HCC is the 4th most common cancer in males with approximately 24.8 cases per 100,000 cancer cases.
Risk factors for HCC include:
These risk factors typically lead to liver cirrhosis which is present in 80-90% of patients with HCC. However, HCC can develop even in the absence of underlying liver cirrhosis especially in people with of chronic hepatitis B infection.
The risk of HCC in people with Hepatitis B infection increases if the person is male, has high hepatitis B viral load, positive HepBeAG indicating active viral replication, genotype C, co-infection with hepatitis C or concurrent heavy use of alcohol. The risk of HCC is decreased but not eliminated with the use of antiviral nucleoside analogue.
3. How is the Screening performed for Liver Cancer?
Screening for liver cancer (HCC) increases detection of early-stage HCC, which then increases the likelihood for curative-intent treatment. Guidelines suggest screening for:
The recommended screening is a half-yearly ultrasound of the abdomen, with or without tumour marker (AFP), based on the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) consensus statement.
4. What is the Diagnosis and Treatment of Liver Cancer?
The diagnosis of HCC in patients with underlying risk factors is usually made by dynamic contrast-enhanced CT or MRI without the need for biopsy. Occasionally, a biopsy may be required for cases with no risk factors for HCC or lesions without the characteristic features of HCC on imaging.Treatment of HCC depends on tumour size, number of lesions, location, presence of spread outside of the liver or invasion of the cancer into the blood vessels, and underlying liver reserve.
If the cancer is confined to the liver:
The approach to treatment of liver-confined HCC varies according to availability of resources and local criteria for liver resection/transplantation. For most patients with HCC limited to the liver, but are not candidates for surgical resection or liver transplantation, liver-directed therapies are preferable to systemic therapy (therapy that targets the whole body) because of the more favourable side effect profile. Examples of liver-directed therapies include transarterial embolization, radiofrequency ablation (RFA) and stereotactic radiotherapy.
If the cancer spreads beyond the liver:
Patients with macrovascular invasion or disease spread outside of the liver are usually considered for systemic therapy rather than liver-directed therapies. Sorafenib has been the main systemic therapy for HCC but recent years have seen newer active agents including immunotherapy that improve survival. Extensive research is being done to combine various modalities of therapy and elucidate role of various systemic therapy in earlier setting.