More People Getting Liver Cancer, Study Finds

by John C. Martin
Article Date: 12-17-03


More people than ever are acquiring primary liver cancer, according
to a study from doctors in Houston.(1)

Hepatocellular Carcinoma
The study focused on hepatocellular carcinoma (HCC), the most common
primary malignant tumor of the liver. People infected with chronic
hepatitis B or C, or cirrhosis, face a substantially increased risk
of developing this cancer.(2)

The disease begins in the cells that make up the liver, and develops
either as a single tumor, or expands to other parts of the liver
later. It's estimated that three out of every four primary liver
cancers are hepatocellular carcinoma.(3)

The cause of this type of cancer is still unclear, but it tends to
arise in people with not only chronic hepatitis infection, but also
those who have spent several years drinking heavy alcohol.(4)

'A Continuing Rise'
In their study, a follow-up to research conducted in 1999(5),
doctors at the Veterans Affairs Medical Center and Baylor College of
Medicine in Houston used a national database that covers nine
geographic regions of the U.S. The database included information
about patients who had been diagnosed with hepatocellular carcinoma,
as well as their outcomes. The investigators used that information
to determine whether numbers of new cases of liver cancer increased
from the 1970s to the 1990s, and whether any increases had begun to
level off.

They found that the number of people diagnosed with primary liver
cancer had doubled between 1975 and 1998. In fact, they reported
that increases were seen in all ethnic groups, and in most age
groups over age 40.

A 1999 study published by the same team found similar trends, and
since they had theorized that the rise in liver cancer cases was
partly linked to hepatitis C infections, "we expected to see a
continuing rise in HCC for several more years," said Hashem El-
Serag, M.D., M.P.H., an assistant professor of medicine at Baylor
College of Medicine, and a study investigator, in an e-mail
interview.

In their earlier study, El-Serag and a colleague found rising rates
of hepatocellular carcinoma between 1976 and 1995, using information
from an epidemiology database.(5)

In their most recent research, the researchers discovered that the
incidence of hepatocellular carcinoma jumped from about 1.5 cases
for every 100,000 people between 1975 and 1977 to three cases per
100,000 population between 1996 and 1998, the last two years
examined in the study.

"There was a 25% increase during the last 3 years of the study
compared with the preceding three years (1993 to 1995)," the team
reported.

The highest incidence of hepatocellular carcinoma was in black and
older people, but men between the ages of 45 and 54 had, by far, the
largest recent upswing in liver cancer rates.

Suggested Causes
The number of people diagnosed with hepatocellular carcinoma began
climbing in the early 1980s, but the reasons were not known. Some
experts have suggested that the cause might be related to the
increase in hepatitis C infections that began in the 1960s and 1970s.

That's when Hepatitis C Virus infections were spread primarily by needle-sharing
among intravenous drug users, transfusion of unscreened blood
products, and unsafe sexual practices.

Other studies also found "an increase in Hepatitis C Virus-associated HCC during
the 1990's, while at the same time, HBV-related-and alcohol-related-
HCC remained relatively stable," El-Serag pointed out, strongly
suggesting a link between rising liver cancer rates and the
increasing incidence of hepatitis C.

Study Drawbacks
Despite the apparently definitive findings, the Houston
investigators admitted several weaknesses of their study. For one,
the geographic regions covered in the research were mostly urban, so
information about people with liver cancer living in rural areas was
not available.

In addition, patients in the study were classified as white, black
or "other", limiting the ability to measure rates of liver cancer
specifically among Hispanics or Asian-Americans. And because no
blood tests for hepatitis C virus infections were available, the
investigators were not able to make any direct connections between
liver cancer and hepatitis infections.

Possible Solutions?
Controlling the rise in liver cancer cases is "unfortunately" out of
reach, El-Serag told Priority Healthcare. "Therapy for Hepatitis C Virus has the
potential of reducing the incidence of HCC, but given its current
effectiveness and the small proportion of patients who are eligible
to receive and tolerate it, it is unlikely to have a massive effect
enough to counter the current trends," he said.

It's been estimated that about 17,300 new cases of primary liver
cancer and bile duct cancer would be diagnosed in the U.S. in 2003.
Of those, approximately 14,400 were expected to die from the disease.
(3)

1. El-Serag HB et al. The continuing increase in the incidence of
hepatocellular carcinoma in the United States: An Update. Ann Intern
Med 2003 Nov 18;139(10):817-23.
2. American Liver Foundation.
3. American Cancer Society.]
4. American College of Physicians.
5. El-Serag HB, Mason AC. Rising incidence of hepatocellular
carcinoma in the United States. N Engl J Med 1999 Mar 11;340(10):745-
50.