The global burden of liver cancer is substantial. In 2020, there were 905,700 people diagnosed with liver cancer, and 830,200 died from this disease globally. These numbers are expected to rise by more than 55% by 2040, based on the estimates of the International Agency for Research on Cancer and its partner institutions.
While liver cancer is much more common in countries in Southeast Asia and sub-Saharan Africa, a rise in its incidence and mortality rates has also been observed in the United States. According to the recent American Cancer Society (ACS) statistics report, liver cancer incidence rates have more than tripled, and its death rates have more than doubled since 1980. This year, about 41,210 new cases will be diagnosed, and about 29,380 will die of this cancer, based on the same report. Moreover, it is now the fastest-growing cause of cancer death in the country, even if it is less prevalent than lung and breast cancers.
Reasons why liver cancer incidence and death rates are rapidly growing
- Increased exposure to risk factors
The primary causes of liver cancer include hepatitis B, hepatitis C, alcohol consumption, nonalcoholic fatty liver disease, and other causes of liver disease that result in cirrhosis. Among these, hepatitis B—a virus that causes liver damage and spreads through contact with infected blood and other body fluids—was found to be the most common cause of this disease globally. However, in the U.S., less than 5% of liver cancer cases arise from this virus, thanks to vaccinations routinely executed among American children since 1982.
In a 2018 study published in CA: A Cancer Journal for Clinicians, researchers suggest that about 71% of liver cancer diagnoses in the country can be attributable to preventable risk factors. One of these risk factors is hepatitis C—a virus that is only transmitted through contact with infected blood—which accounts for almost 25% of liver cancer cases, according to the study led by Farhad Islami (the strategic director for the ACS’s cancer surveillance research). He explains that this figure reflects the big group of baby boomers with undiagnosed hepatitis C, wherein the virus silently damages their livers for many years. This group in their 50s to 70s has just developed liver cancer. For more information on the link between hepatitis C and liver cancer, read FAQ: Understanding the Link Between Hepatitis C and Liver Cancer.
The same article notes that other preventable risk factors play significant roles in increasing the incidence and death rates. For example, cigarette smoking accounts for more than 22% of the incidence and death rates. A meta-analysis report in 2009 indicated that smokers have about 51 to 70% increased liver cancer risk.
Another big contributing factor is obesity. About 36% of liver cancer diagnoses from 2008 to 2011 were linked to obesity. Having excessive body weight creates fatty infiltration that can eventually result in fibrosis or the first stage of liver scarring that can lead to cirrhosis. This can also result in nonalcoholic steatohepatitis (NASH), which is a serious type of fatty liver disease that can damage cells and eventually lead to cancer.
Outside the risk groups, there are also liver cancer patients whose causes are not identified. In 2000, a man of Brazilian origin was diagnosed with anemia after a routine blood test for a cosmetic surgical procedure. Two years later, his doctors found out that the cause of his anemia was fibrolamellar carcinoma (FLC). It is a rare form of liver cancer that only makes up less than one percent of all primary liver cancers.
FLC is not associated with traditional risk factors, like those mentioned above, but over the five years of studying this case, researchers found the link of FLC to a genetic error that fuses two genes.
- Limited Treatment Options
The key to reducing liver cancer death rates is prevention. Unfortunately, a screening test for this disease does not exist, and most people diagnosed with the disease have a poor prognosis. Due to these reasons, the overall five-year survival rate for liver cancer in the U.S. is only 18%.
Treatment options like surgery and targeted therapies are supposed to be effective if only the cancer is detected at an earlier stage. In most cases, more than one tumor can be found within the liver itself. Another problem is that many of the risk factors result in cirrhosis. A cirrhotic liver is a premalignant organ, so the tumor is likely to grow back even after taking it out through surgery.
- Lack of education
Previous studies have shown that access to limited resources is a contributing factor to developing liver cancer. For the first time, a study conducted by the senior principal scientist of surveillance research at ACS, Jiemin Ma, and her co-authors investigated the link between educational attainment and the risk of liver cancer. The authors found that adults who have less education showed a higher risk of liver cancer death.
How to lower liver cancer incidences and deaths
According to experts, a substantial decrease in liver cancer rates can be achieved through primary prevention. They estimate that at least a 3% yearly decrease must be achieved by various countries across the world.
For this to be possible, public health officials must reinforce current liver cancer preventive measures to decrease incidence rates and prepare for possible increased demand for resources to manage the care of liver cancer patients to decrease mortality rates. Some of these preventive measures include addressing hepatitis B and C transmissions. For example, routine testing proactively detects the infection; thus, the infected person can take actions to prevent passing the infection to other people at risk. Also, according to the Centers for Disease Control and Prevention, the transmission of hepatitis B from pregnant mothers to newborns can be prevented in the infection is identified, and newborns are treated within the first 12 hours after birth.
