The short answer
WHO says hepatitis B and C are the main causes of cirrhosis and liver cancer in Japan. Vaccines and antiviral treatment are ways to prevent or treat hepatitis. Alcohol and fatty liver disease can also damage the liver.
Hepatitis B and C are the main causes of cirrhosis and liver cancer in Japan (WHO).
Hepatitis B vaccination and antiviral treatment are ways to prevent or treat hepatitis.
Heavy alcohol use can damage the liver.
People at higher risk may be offered regular liver checks to catch cancer early.
Choose how you want to read this
The whole article, with every detail and caution.
The simple answer
This page explains why liver cancer is common in Japan and how it is being prevented. Liver cancer in Japan is closely tied to long-term viral hepatitis, mainly hepatitis B and C. These infections slowly damage the liver over many years. Alcohol and fatty liver disease can also damage the liver. Vaccines and antiviral treatment are ways to prevent or treat hepatitis. Ask your doctor about regular checks if you are at higher risk.
Hepatitis: the leading cause
For decades, a large share of Japan's liver cancer has been linked to long-term infection with hepatitis B or hepatitis C. These viruses can live in the liver for years. They quietly cause swelling (inflammation) and scarring. Over time, that damage can lead to cirrhosis, which is heavy scarring of the liver, and then to liver cancer.
Many people with hepatitis do not know it. Testing is how it is found.
Progress through vaccines and antivirals
A vaccine protects against hepatitis B. Ask your doctor whether you need it.
Antiviral medicines have changed care completely. Newer oral antiviral medicines now cure about 9 in 10 people with hepatitis C within 3 to 6 months, according to WHO. Japan has offered free hepatitis screening since 2002 for people aged 40 to 70, and a program since 2008 that lowers treatment costs.
The lesson is powerful: when a cancer has an infectious cause, preventing or treating that infection can prevent cancer.
Alcohol and fatty liver
Not all liver cancer comes from hepatitis. Heavy alcohol use damages the liver and raises cancer risk. Fatty liver disease, a buildup of fat in the liver, can also damage the liver. Limiting alcohol helps protect the liver. Ask your doctor what else you can do.
Catching it early
Some people already have long-term liver disease or hepatitis. For them, doctors often recommend regular liver checks to look for cancer early. These are usually ultrasound scans and blood tests. In this higher-risk group, the checks can find liver cancer when it is smaller and easier to treat.
This is a form of targeted screening: not for everyone, but for those whose risk is known to be higher.
A changing mix of causes
WHO says hepatitis B and C are the main causes of cirrhosis and liver cancer in Japan. Testing and antiviral treatment can reduce that damage. Protecting the liver also means limiting alcohol.
What this means for you
Two simple questions are worth asking your doctor:
- Should I be tested for hepatitis B or C?.
- Do I need the hepatitis B vaccine?.
Many infections go unnoticed. Testing can open the door to treatment that protects your liver.
If you have liver disease or a hepatitis infection, ask whether regular liver checks are right for you. For everyone, limiting alcohol and keeping a healthy weight support liver health. These steps will not remove all risk, but they can shift the odds.
Sources
- National Cancer Institute, liver cancer
- National Cancer Center Japan, liver cancer statistics
- CDC, viral hepatitis
- World Health Organization, hepatitis
Before you go
This article is for education only and is not a substitute for medical advice. Talk with a healthcare professional about your personal cancer risk, symptoms, screening, or treatment options.
Cancer information should be clear, kind, and accessible to everyone. If this article helped you, consider supporting Cancer Explained so we can create more free, easy-to-understand cancer education for patients and families. Support is always optional, and every reader is welcome here.
Common questions
What causes most liver cancer in Japan?
WHO says hepatitis B and C are the main causes of cirrhosis and liver cancer in Japan. Alcohol and fatty liver disease can also damage the liver.
Can liver cancer be prevented?
Hepatitis B vaccination prevents that infection, and antiviral medicines can treat hepatitis C. Ask your doctor what else applies to you, including limiting alcohol.
How is liver cancer caught early?
People with long-term liver disease or hepatitis may be offered regular checks, such as ultrasound scans and blood tests, to catch cancer early when it is more treatable.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Talk with a trained specialist or navigator
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Last updated: 2026-10-16Next planned review: 2027-07-08
Review details and limits
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source checked. This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Words to know
Tap any term to see what it means.
Knowledge check
0 of 4 answered
This self-assessment checks understanding of educational content only. It is not medical advice.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.