“90% of liver cancer, which has a high mortality rate, has a cause… It can be prevented if managed.”

“In the extreme case of the above, there is no problem with life even if total excision is performed. But the liver is different. 90% of patients with liver cancer have cirrhosis or hepatitis B at the time of diagnosis. Since there is such a chronic liver disease throughout the liver, it is difficult to cure cancer through resection. Even if part is removed, the cancer is more likely to recur in the remaining area. Hepatocellular carcinoma is more difficult to treat than other cancers in that it is necessary to catch both rabbits, not only cancer but also chronic liver disease treatment.”

The liver performs indispensable functions in our body, such as detoxification, protein synthesis, immunity, and storage and release of nutrients. In an interview with the Segye Ilbo on the 26th, Director Yoo Su-jong (Professor of Gastroenterology, Seoul National University Hospital) of the Korean Liver Cancer Society Academic Committee explained why liver cancer has a higher mortality rate and a lower relative survival rate than other cancer types.

Liver cancer is the 7th most common cancer in Korea after thyroid, lung, colon, stomach, breast and prostate. In 2020, there were 15,152 liver cancer patients. The number of patients may be relatively low, but the story changes when looking at the mortality rate. Cancer is the second leading cause of death after lung cancer. The death toll in 2021 alone reaches 10,255. While the 5-year relative survival rate for thyroid cancer, breast cancer, and prostate cancer is 90-100%, the 5-year relative survival rate for liver cancer is only 38.7%.

Another characteristic that distinguishes it from other carcinomas is that 90% of liver cancers have a causative disease. These are viral hepatitis and alcoholic hepatitis. Among them, hepatitis B (60-70%) accounts for the highest proportion, followed by hepatitis C (10-15%) and alcoholic hepatitis (10-15%). Liver cancer of unknown cause is only 10%. Hepatitis A is an acute hepatitis that does not become chronic and does not lead to liver cancer. In other words, it is a sequence that leads to cirrhosis, in which the liver hardens due to chronic hepatitis, such as viruses, alcohol consumption, and fatty liver disease, and then to cancer.

However, Professor Yu stressed that “70 to 80% progress sequentially to chronic hepatitis, liver cirrhosis, and liver cancer, but in 20 to 30%, liver cancer develops directly from chronic liver disease.”

Hepatitis B has a vaccine, but why does it account for such a high proportion of liver cancer? This is a point where doubts may arise about the effectiveness of the vaccine or the vaccination rate.

Professor Yoo said, “The surface antigen positivity rate for hepatitis B in Koreans surveyed in 1982 was 8.6%, but after the development of a hepatitis B vaccine, the prevalence rate has decreased. The preventive effect of vaccines was emphasized. He explained, “However, the prevalence rate is still high for those born before 1995, when vaccination was recommended for newborns.” As chronic hepatitis B is difficult to cure, it means that the prevalence of the ‘pre-vaccine generation’ will inevitably continue. For hepatitis B patients without a cure, it is best to prevent progression to cirrhosis and liver cancer by administering antiviral drugs when liver levels rise.

On the other hand, the risk of hepatitis C is expected to decrease in the future as a drug that cures 99% of hepatitis C infection after 8 to 12 weeks has been developed. Professor Yu said, “There is no vaccine for hepatitis C, but ‘prevention through treatment’ has become possible because an antiviral drug that can be cured has been developed. In the future, we expect that hepatitis C itself will disappear and liver cancer caused by hepatitis C will also disappear.”

The Korean Liver Cancer Society recommends two tests (hepatic ultrasound + blood test (serum alpha-fetoprotein test)) twice a year for early detection of liver cancer high-risk groups such as hepatitis B and C patients. Considering that most cases of gastric cancer in the national cancer screening are two-year cycles, it is quite short.

“The reason why liver cancer high-risk groups are screened every 6 months is because of the ‘tumor doubling time’, in which cancer grows twice as much. It takes two weeks for the cancer to grow twice as fast and one year for the longest, and the median is six months. There is no difference in the liver cancer diagnosis rate between 3 months and 6 months, but the detection rate and patient survival rate of early-stage liver cancer increase at 6 months compared to the 12-month period. Considering that the size at which cancer is clinically found is 1 cm, it becomes 4 cm after two tumor doubling times, making curative treatment difficult, so it is to detect it before that.”

In the long term, what if all the younger generations are vaccinated against hepatitis B and hepatitis C is cured? Instead of liver cancer disappearing, it is highly likely that the vacancy will be filled by an ‘other’ cause. Obesity and alcohol are on the rise due to westernized eating habits.

Professor Yoo said, “Metabolic syndrome and fatty liver disease related to obesity and diabetes also increase the incidence of hepatocellular carcinoma. Alcohol, smoking, and obesity increase the risk of liver cancer, so we must avoid them.”

He also advised, “Sometimes, if you use herbal medicines or health supplements incorrectly, claiming to protect the liver, toxic hepatitis can damage liver function, so you must consult with a specialist.”

Reporter Jeong Jin-soo jen@segye.com

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