Why liver cancer is common in the Philippines
Q. Our 68-year-old neighbor died of liver cancer last week, less than six months after he was diagnosed with the disease. I understand that the outlook for liver cancer patients is very poor. Why is this so? Also, why is this form of cancer common in the Philippines when it is rare in the US? Is there a way to prevent this form of cancer?
Celso N., Cebu City
A. Liver cancer has a poor prognosis or outlook because it is often diagnosed very late in its course. It usually presents no symptoms until the tumor is already at least 10 cm in size, at which time the disease has typically already spread and is in the advanced stage.
Most liver cancer patients die within a year of diagnosis, and the five-year survival rate for the disease (if no treatment is undertaken) is less than five percent. Even with treatment, the five-year survival rate for liver cancer is still a low 35 percent.
Liver cancer is only the eighth most common cancer worldwide, and as you mentioned, it is relatively rare in the US (and for that matter, other developed countries). In the Philippines and other underdeveloped countries, however, the incidence of liver cancer is rather high. The latest DOH advisory shows that liver cancer is the third most common form of cancer among Filipinos—in men, it is the second most common, while in women, it is the ninth most common.
Liver cancer is relatively common in our country primarily because many Filipinos suffer from cirrhosis of the liver, a major risk factor for liver cancer. Cirrhosis of the liver precedes 80 percent of all liver cancers; thus, any condition that predisposes to cirrhosis indirectly causes liver cancer. The usual cause of liver cirrhosis among Filipinos is chronic hepatitis B, a major public health problem in the country. Chronic hepatitis B afflicts between 10 and 12 percent of all Filipinos (i.e., more than 8 million Filipinos). Other less significant causes of cirrhosis are hepatitis C infection and alcoholism.
Another risk factor for liver cancer that adds to the high incidence of the malignancy among Filipinos is aflatoxin. Aflatoxin is a poisonous substance that damages the liver and may cause liver cancer. It is produced by certain species of molds that grow in foodstuff such as peanuts, corn, rice, dried fruits, spices, crude vegetable oils, cocoa beans, and copra, as well as milk and milk products from cattle that have consumed contaminated feed. The high temperature and relative humidity that prevail in the Philippines and the often improper storing, processing, and handling of foodstuff are the reasons why the aflatoxin content of the above-mentioned food products is frequently above the acceptable level.
Other less common causes of liver cancer in the Philippines are certain chemicals such as vinyl chloride (used in certain industries), and estrogens and androgens—hormones that are present in oral contraceptives and anabolic steroids, respectively.
The outlook for liver cancer is poor, but the disease is preventable because the major risk factors for the disease have already been identified. Measures that can significantly reduce one’s risk for cancer of the liver include vaccination for hepatitis B, avoidance of alcohol, and proper storage of foodstuff.
(Email inquiries on health matters to email@example.com)