December 14, 2005

Betel quid chewing increases pharyngeal cancer risk

NEW YORK (Reuters Health) - Betel quid chewing is a strong
independent risk factor for pharyngeal cancer (cancer of the
back of the throat), but not laryngeal cancer (cancer of the
voice box), according to findings published in the
International Journal of Cancer.

Chewing betel quid, which consists of betel leaf from the
Piper betle vine, is popular in many parts of Asia. Betel quid
is chewed for its stimulant effects, to satisfy hunger and as a
social and cultural practice.

"The risks of betel quid chewing with or without tobacco,
alcohol drinking and cigarette smoking have been well explored
in the oral cavity but not in the pharynx and larynx," Dr.
Ying-Chin Ko, of National Health Research Institutes, Taiwan,
and colleagues write.

The investigators therefore examined 148 men with
pharyngeal cancer, 128 men with laryngeal cancer, and 255 men
without either cancer who served as "controls."

Betel quid chewing was significantly and independently
associated with the risk of pharyngeal cancer, increasing the
risk by nearly eight-fold. However, no significant association
was observed between betel quid chewing and laryngeal cancer.

Those who consumed more than 20 quid a day or swallowed the
betel quid juice had an even high risk -- the investigators
observed a synergistic effect of these risk factors for both
pharyngeal and laryngeal cancer.

The quantity of exposure and the direct contact of the
carcinogen to the mucus membrane appear to enhance the
carcinogenic process, Ko and colleagues suggest. "Further
studies to explore the associations between betel quid chewing
and cancers of other sites of the digestive tract, for example,
the esophagus and stomach, and the effects on other systems of
humans are necessary."

SOURCE: International Journal of Cancer, December 2005.