Mortality rates from liver cancer in the United States have doubled since the mid-1980s, and they are increasing faster than for any other cancer, according to a new analysis by the American Cancer Society.
The study was published online June 7 in CA: A Cancer Journal for Clinicians.
From 2009 to 2013, the average incidence of liver cancer per year was 7.7 per 100,000. The average annual death rate from liver cancer for those years was 6.3 per 100,000.
The rates have been increasing during the past few decades ― since at least 1975 for incidence and since 1980 for mortality, the researchers note. Liver cancer mortality rates for 2009-2013 were double those seen in the 1980s.
Notably, both incidence and death rates were twofold to threefold higher in men than in women, the researchers add.
Lead author Farhad Islami, MD, PhD, strategic director, Cancer Surveillance Research, American Cancer Society, Atlanta, Georgia, commented that improvements in survival rates have been recorded in past years, but the prognosis associated with hepatocellular carcinoma (HCC) is still poor, with only 1 in 5 patients surviving 5 years after the diagnosis.
The most common histologic type of primary liver cancer was HCC, which makes up more than 70% of liver cancer cases in the United States.
It is anticipated that 41,000 new cases of liver cancer will occur this year across the United States, along with 29,000 deaths from the disease, the investigators warn.
Modifiable Risk Factors
Approximately 60% of all liver cancers in the United States are caused by potentially modifiable risk factors, the researchers indicate. For example, it has been estimated that among Medicare recipients, the largest proportion of cases of HCC, at 32%, are caused by metabolic disorders, including obesity. A smaller proportion of cases of HCC are caused by hepatitis C virus infection (21%), excessive alcohol intake (13%), and smoking (9%).
Hepatitis B virus (HBV) infection was associated with only 4% of all HCCs, according to the current analysis.
"Differences in risk factor prevalence accounts for much of the variation in liver cancer rates by sex, age group, state and race/ethnicity," Dr Islami and colleagues observe. For example, for Hispanics living in Texas, who are primarily of Mexican descent, death rates are higher than they are among Hispanics living in Florida, most of whom are of Cuban or Puerto Rican descent.
Researchers speculate that the higher death rate among Hispanics of Mexican descent reflects a higher prevalence of chronic HCV infection, being overweight, or the presence of nonalcoholic fatty liver disease.
The prevalence of HCV infection is relatively high, at 2.6%, among baby boomers, who account for approximately 80% of all liver cancer cases caused by HCV infection, the researchers observe.
"Overall, the proportion of all HCCs during 2000 through to 2011 attributable to HCV was 17% in whites, 21% in Hispanics, 30% in Asians, and 36% in blacks," the investigators state.
In contrast, HBV infection accounted for fewer than 5% of liver cancer cases in the United States.
The study authors point out that the prevalence of obesity has increased substantially over the years in all racial and ethnic groups.
"In most cases, patterns of obesity prevalence in each racial/ethnic group correspond to liver cancer death rates," the authors note. Diabetes also increases the risk for liver cancer in men and in women.
Patients with nonalcoholic fatty liver disease are similarly at increased risk for liver cancer, and the incidence of nonalcoholic liver disease increased by 31% during 2011-2012.
"Alcohol consumption increases liver cancer risk by approximately 10% per drink per day (eg, a 3-fold increased risk for someone consuming 8 drinks per day," the investigators point out, and "smoking increases liver cancer risk by approximately 50%."
Many liver cancers could be prevented by modifying various risk factors for the malignancy, the study authors point out.
"The burden of liver cancer in the United States is significant and is expected to increase in the decades to come," Dr Islami and colleagues state.
"However, most liver cancers are potentially preventable, and interventions to curb the rising burden of liver cancer and reduce racial/ethnic disparities should include the targeted application of existing knowledge in prevention, early detection, and treatment."
The authors have disclosed no relevant financial relationships.
CA Cancer J Clin. Published online June 7, 2017. Full text
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Cite this: Death Rate From Liver Cancer in US Now Double That in 1980s - Medscape - Jun 09, 2017.