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.