Risk of esophageal cancer high in Taiwan due to 'Asian Flush'

As Taiwanese lead the world in the 'Asian Flush,' esophageal cancer risk is high

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Before (left) and after (right) drinking alcohol.

Before (left) and after (right) drinking alcohol. (By Wikimedia Commons)

TAIPEI (Taiwan News) -- After news broke of Yulon Group Chairman Kenneth Yen's death (嚴凱泰) on Monday due to esophageal cancer, doctors are warning Taiwanese that those with the so-called "Asian Flush," have a much higher risk for the disease.

Following the deaths of Yen and the actor Andi (安迪) from esophageal cancer, experts say that the two men may have been exposed to cigarettes and alcohol for a long period of time, which would have increased their risk of contracting the disease. In particular, those who experience the "Asian Flush," a flushed reaction many people in East Asia have to alcohol, may be much more prone to cancer when their esophagus is frequently inflamed.

Chao Ying-kai (趙盈凱), Director of Thoracic Surgey at Chang Gung Memorial Hospital told SET News that according the statistics, the two earliest forms of cancer that appear in Taiwan are head and neck cancer and esophageal cancer. Chao said 2,500 people are diagnosed with esophageal cancer every year, the patients are mainly male, and the average age of occurrence is 50.

In his outpatient clinic, Chao says that there are many patients who develop esophageal cancer as early as 40 years of age. Chao said that esophageal cancer is caused by long-term stimulation of esophageal mucosa and reapted inflammation.

This form of cancer can be divided into squamous epithelial cancer and adenocarcinoma. The former is the most common type in Asia, accounting for up to 90 percent of cases, while in the West it comprises less than 30 percent of cases.

Chao said it's mainly brought on by bad habits, such as smoking, drinking alcohol, and chewing betel nuts, and there is not believed to be a strong genetic component. It is also said that those who swallow the juice when chewing betel nuts have an increased risk of developing esophageal cancer.

Chao theorized that because Andi and Yen both died in their 50s, contributing factors could have been the frequent pressure to smoke, drink, and overeat during social gatherings in their respective industries. Chao said that these habits had a cumulative effect over a long period of time, probably at least 15 to 20 years, in his estimation.

The second type of esophageal cancer, adenocarcinoma, is found about equally in men and women in Asia and is caused by acid reflux.

Chao especially emphasized that people who are prone to the Asian Flush should be extra cautious. Chao said that people who have this reaction are not drunk, but rather have a deficiency of the liver enzyme ALDH2.

The enzyme aldehyde dehydrogenase (ALDH2) plays a crucial role in human metabolism of alcohol, but people who easily become flushed even after only having one drink, may have the genetic mutation of this enzyme responsible for what is often referred to as the Asian flush or "Asian glow" response. Two alleles of ALDH2 -- ALDH2*1 and ALDH2*2 -- are genetic mutations that most often appear in populations of East Asian countries such as China, where about 35% of the population has the mutation, while 30% of Japanese and 20% of Koreans have the variant.

Three general studies have found that the two Asian alleles of the ALDH2 gene result in very different physical responses to the ingestion of alcohol. Those who carry the ALDH2*1 allele, may experience a mild blush, but little in the way of physical discomfort. However people with ALDH2*2 mutation will become flushed after consuming even small quantities of alcohol, of whom about 6% are completely unable to metabolize the acetaldehyde resulting from drinking. In addition to a deep reddening of the face, people in this second group may also experience palpitations, nausea, vomiting and other physical discomfort.

Some studies have pointed out that under same stimulation of the esophageal mucosa, those who lack this enzyme are more likely to experience a deformation of the esophageal mucosa. People who drink alcohol regularly and have the ALDH2 alleles, are 50 times more likely to develop esophageal cancer than those with the alleles who are non-drinkers.

As difficult as it may be, Chao said the best form of prevention is to stop smoking, drinking alcohol, and chewing betel nut. He also suggested that high-risk groups be examined regularly and undergo endoscopic screening with esophageoscope and gastroscopy, once a year, starting at the age of 40.

Taiwan has the dubious distinction of having the highest Asian flush rate in the world at 47 percent.