Stalking a Cancer That's Silent and Deadly

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Stalking a Cancer That's Silent and Deadly

By JANE E. BRODY

Published: October 11, 2005

http://www.nytimes.com/2005/10/11/health/11brod.html

You don't hear much about liver cancer, but its incidence is

increasing faster than any other cancer in the United States. That

increase is expected to continue for two more decades.

Liver cancer is also one of the most deadly cancers, typically fatal

within a year of diagnosis, unless, as rarely occurs, it is found

very early. This fact alone suggests that people at high risk of

developing the cancer may want to consider periodic screening with

whatever tests are available.

More Columns: Personal Health That in turn suggests that people at

high risk should know that they are and find out whether screening

will be effective.

Many people are confused about liver cancer. Only cancers that

originate in the liver are liver cancers. Cancers of the colon, lung

or breast, among others, often spread to the liver, prompting the

confusion. But every cancer, regardless of where it may spread,

retains the name and cellular characteristics of its origin.

Liver cancer is one of the most common cancers in the world,

especially prevalent in Southeast Asia and sub-Saharan Africa. In

the last quarter-century, Japan, for example, has experienced an

epidemic of liver cancer, now the third leading cause of cancer

deaths among its men and the fifth leading cause among the women.

A Rising Scourge

Primary liver cancer is still relatively rare in the United States,

where it is the 20th most common type of cancer. But just last week,

The Associated Press reported that cases are rising as rapidly as

4.5 percent among black men and 5 percent among Hispanic women.

Because liver cancer is usually not found before symptoms of

advanced disease develop, it is also the eighth most common cause of

cancer deaths in this country.

The striking increase in liver cancers here and in other developed

countries is a result of chronic and usually silent infections by

the hepatitis B and C viruses, which are spread by blood and attack

the liver. These viral infections, which damage liver cells, can

lead to primary liver cancer 30 years or more after an infection

takes hold.

Genetic material of the hepatitis B virus incorporates itself into

the DNA of liver cells, subverting normal functions and, ultimately,

causing cancer. The hepatitis C virus works differently; it is

believed to disrupt the action of a gene called P53 that normally

suppresses tumor formation.

Like hepatitis B, chronic hepatitis C infections can also cause

cirrhosis, a scarring of the liver. When the damaged liver tries to

repair itself, mutations can occur that result in uncontrolled cell

growth. About 5 percent of people with cirrhosis from any cause

eventually develop liver cancer.

But with screening of blood supplies for hepatitis B virus in place

since the late 1980's and with current immunizations of infants and

some adults with hepatitis B vaccine, the incidence of liver cancer

brought on by this virus should be reduced in years to come.

Although potential blood donors and donations are now checked for

the hepatitis C virus, many people became infected before the virus

was identified. No vaccine has been developed against this infection.

Many people continue to put themselves at risk of developing a

hepatitis C infection through exposure to contaminated needles as a

result of drug use, tattooing and body piercing. and unprotected sex

with people who may carry the virus. Hepatitis C accounts for half

the cases of primary liver cancer in the United States.

Another important cause of liver cancer is alcohol abuse. Alcohol

damages the liver and over the years can result in cirrhosis. In

fact, cirrhosis from chronic alcohol consumption, especially when

combined with a chronic hepatitis C infection, is the most common

cause of liver cancer in the developed world.

Further, it is more likely to develop a decade or more after a

person with alcohol-induced cirrhosis stops drinking, when the liver

generates new cells to repair the damage caused by alcohol. Of

course, people who continue to abuse alcohol risk an early demise

from liver failure.

Other factors known to cause liver cancer are exposure to certain

industrial chemicals like vinyl chloride and a poison called

aflatoxin B, produced by a fungus, Aspergillus flavus, that can grow

on foods like peanuts and other nuts, rice, soybeans, corn and wheat.

The Food and Drug Administration monitors the American food supply

for this toxin. But in southern China and sub-Saharan Africa,

chronic consumption of aflatoxin B, believed to suppress the P53

gene, is a leading cause of liver cancer.

Concerns have also been raised about substances like estrogen and

anabolic steroids that can cause the development of benign liver

tumors, which may ultimately become malignant.

A genetic disease called hemochromatosis, which causes excess iron

to accumulate in the liver and other organs, also results in liver

cancer in up to 30 percent of the people with this disorder.

Other risk factors include smoking, diabetes and mutations in the

genes BRCA1 and 2, which are most often linked to breast and ovarian

cancers.

As with the viral infections that can cause it, liver cancer is

often a silent disease. Symptoms typically result only when the

cancer grows to a size that cannot be cured by simple surgery or

when it spreads to other organs. After that point, it cannot be

cured.

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More Columns: Personal Health The symptoms include pain in the

upper right side of the abdomen, possibly extending to the back and

shoulder; a swollen abdomen; weight loss; loss of appetite and

feelings of fullness; weakness or fatigue; nausea and vomiting;

fever; and jaundice, evidenced by yellowing of the skin and eyes and

by dark urine.

People at high risk of developing liver cancer are not likely to

want to wait until they have symptoms to find out that cancer - most

likely advanced cancer - is the cause.

Flaws in Screening

Far better to find a liver cancer while it is still a silent

disease, because early detection is crucial. Liver cancer grows

quickly, doubling in size every four months.

There is still no completely accurate screening test for liver

cancer. A blood test for alpha-fetoprotein (AFP) is sometimes used,

though other conditions, including noncancerous liver diseases, can

cause AFP levels to increase.

Abdominal ultrasound, a noninvasive test that does not involve

exposure to radiation or dyes, can sometimes reveal an early liver

tumor. A CT scan, with or without a dye, uses X-rays to produce

cross-section images of the liver, and an M.R.I. can create a

similar image.

If a suspicious lesion is found, a biopsy can determine whether it

is cancer. If the liver is not cirrhotic and the tumor is small,

confined to one lobe of the liver and not near a main artery, vein

or bile duct, surgery can be curative.

If the cancer is more advanced, treatments like chemotherapy, radio

frequency ablation and alcohol injection into the tumor can slow its

progress. The surest cure for an early liver cancer is a liver

transplant. The patient's entire liver is removed and replaced with

a healthy liver from a cadaver or a lobe from a living donor.

Because the liver regenerates, the donor and recipient soon have

full-size livers.

About 18,000 patients are waiting for liver transplants, but only

4,000 cadaver organs become available each year. Often while

patients wait for donor organs, their cancers become too large to be

cured by transplants.