Hepatocellular carcinoma is a common cancer worldwide. The incidence in the East is very much higher due to endemic chronic hepatitis B virus (HBV) infection in the population. The incidence of HCC has been increasing steadily in USA and the major risk factor for HCC in US is chronic hepatitis C virus (HCV) infection. In 1975, the total incidence of HCC was approximately 1.59 per 100,000 person-years. By 2006, this had reached 4.82 per 100,000 person-years and this increase has been attributed to the increasing numbers of Asian immigrants in the United States. However, a presentation at the recent 101^st Annual Meeting of the American Association for Cancer Research (AACR) has come up with a surprising culprit (Abstract 1816, presented Arpil 19, 2010).

Researchers from the National Cancer Institute (NCI) reviewed data from the NCI SEER database. The case population studied consisted of 5607 people diagnosed with HCC. They examined the odds ratio of an individual developing HCC with the risk factors of HCV infection, HBV infection, alcohol-related disease, rare metabolic disease, diabetes and obesity. (Odds ratio tells you how much more likely it is that you are going to develop the condition compared with someone without the risk factor.) HCV infection has the highest odds ratio of 44.26 (ie 44 x more likely than a non HCV infected person). The odds ratios for HBV infection, alcohol-related disease, rare metabolic disorder, diabetes and obesity were 13.37, 4.43, 3.51, 2.37 and 1.53, respectively. However, the researchers found that diabetes was associated with the greatest percentage of cases (33.5%). The other associations were alcohol-related disorders (23.9%), HCV infection (20.7%), HBV infection (5.7%), rare metabolic disorders (3.1%) and obesity (2.7%).

The incidence of obesity and diabetes mellitus is increasing worldwide and the Asian population has not been spared. While chronic HBV infection is the most important risk factor for HCC in Asia, the general population and clinicians need to be aware that diabetes and obesity are also associated with HCC. The above study found that 67.9% of Asians with HCC had one or more of the identified risk factors. Both obesity and diabetes can be helped by adopting a prudent life style - maintaining a healthy body starts with you!

Two weeks ago I saw a patient who is known to be a carrier of hepatitis C virus (HCV). He was diagnosed in 2005 but for the last few years had not had regular surveillance of his liver. He had felt bloated for a few months and saw his doctor recently. Subsequent investigations showed he had bilobe liver cancer (hepatocellular carcinoma, HCC) in a cirrhotic liver. Curative surgical resection was not an option as he had lesions in both the right and left lobes of the liver. [The best scenario for any patient with HCC is the presence of a small (< 2cm in diameter) tumour confined to one lobe of the liver (i.e. stage I / II cancer).] Would the situation be different if he had had regular surveillance?

Researchers from Hiroshima Prefectural Hospital reported the results of a study evaluating the usefulness of regular check-ups by ultrasonography and contrast-enhanced imaging for early detection of HCC in patients infected with HCV (J Gastroenterol 2009, Oct 29; epub). From April 2001 to March 2007, 240 consecutive HCV patients with HCC were studied. These patients could be classified into 3 groups:- Group A patients had their HCC diagnosed by regular, imaging surveillance; Group B patients had their HCC detected during scheduled doctor visits for liver disease or other diseases such as diabetes and Group C patients had their HCC detected when they felt a need to visit a doctor. The study found that the prevalence of single tumour at the time of diagnosis was 66% in group A patients. Group B patients had a prevalence of 48% while it was only 24% in group C patients. The percentage of stage I and II patients were 83% for group A, 53% for group B and 24% for group C. The number of patients who underwent curative procedure (surgical resection / ablation) was 99/124 (80%) in group A, 42/79 (53%) in group B and 10/37 (27%) in group C.

At the present moment, we cannot, with one blood or x-ray test, predict the risk of developing HCC in anyone who is a carrier of the hepatitis B (HBV) or C virus. The only way we can help these carriers is to perform regular blood and x-ray screening at 6 monthly intervals. The surveillance / screening is to afford us a chance to detect the liver cancer at an earlier stage. It does not stop the development of the cancer. If the liver cancer can be detected at an earlier stage, the chance of having a curative treatment is much higher.     

To all HBV & HCV carriers and people with liver cirrhosis, please remember to go for regular screening. Please do not wait until you have symptoms. It could be a bit late by then.

The Nobel Assembly in Stockholm has just announced the winners of the 2008 Nobel Prize in Medicine. The winners are Harald zur Hausen of Germany and the French researchers Francoise Barre-Sinoussi and Luc Montagnier. Zur Hausen was cited for finding human papilloma viruses that cause cervical cancer, the second most common cancer among women. Barre-Sinoussi of the Institut Pasteur in Paris and Montagnier, Director of the World Foundation for AIDS Research and Prevention, were cited for their discovery of human immunodeficiency virus (HIV) which causes AIDS. Kaposi sarcoma is common in AIDS patients.

There are many viruses which lead to the development of cancers in humans. At present, pancreatic cancer has not been linked to a specific virus. However, a recent publication from the University of Texas M. D. Anderson Cancer Center suggested a possible association between hepatitis B virus (HBV) and pancreatic cancer (J Clin Oncol 2008; 26: 4557 – 4562). The aim of their study was to determine whether HBV and hepatitis C virus (HCV) infections increase the risk for the development of pancreatic cancer. The researchers studied the blood samples from 476 pancreatic cancer patients and 879 age-, sex- and race-matched healthy controls. The samples were tested for the presence of HCV antibodies (anti-HCV), HBV surface antigen (HBsAg), antibodies to HBV core antigen (anti-HBc) and antibodies to HBsAg (anti-HBs). They found that the prevalence of past exposure to HBV, indicated by the presence of anti-HBc, was significantly higher in pancreatic cancer patients (7.6%) than controls (3.2%). Compared to controls, people who had had previous exposure to HBV but had developed immunity are 2.3 times more likely to develop pancreatic cancer. Diabetes also significantly increased the risk of pancreatic cancer in patients with past exposure to HBV. If you are an HBV carrier, you are 4 times more likely to develop pancreatic cancer. Interestingly the researchers did not find a significant association between HCV infection and pancreatic cancer.

The researchers have not proved that HBV causes pancreatic cancer. They have shown an association between HBV infection (past or present) and pancreatic cancer. They have suggested that perhaps because of their (the liver and pancreas) close proximity and sharing of blood supply and ducts, the pancreas may suffer collateral damage from the HBV infection and thus be predisposed to the development of cancer.

With many more years of research, it may be possible that a specific virus might be identified as the causal agent for pancreatic cancer. Until then we can only be vigilant and pay more attention to individuals with associated risk factors for pancreatic cancer. These are:- a history of diabetes mellitus, cigarette smoking, a

positive family history of cancer and possibly past / present history of HBV infection.