Pubdate: Mon, 20 Dec 1999 Source: The Examiner (Ireland) Copyright: Examiner Publications Ltd, 1999 Contact: http://www.examiner.ie/ Author: Conor Keane CANNABIS SMOKING LINKED TO CANCERS OF HEAD, NECK DRUG pushers might soon have to issue health warnings when selling cannabis -- Ireland's most popular illegal drug -- following the discovery in the US that smoking marijuana can cause cancer. In a medical first, researchers at UCLA's Jonsson Cancer Centre are reporting that smoking cannabis increases the risk of head and neck cancers. Some ageing hippies might now decide its the time to come off the grass following the results of an epidemiological study published in the peer reviewed journal Cancer Epidemiology Biomarker and Prevention. Up to this, laboratory and clinical studies have indicated that marijuana use may be related to molecular alterations in the respiratory tract, changes that may lead to cancer. This is the first study to examine whether smoking marijuana increases risk of head and neck cancers, said Dr Zuo Feng Zhang of UCLA's Jonsson Cancer Centre, a professor in the Department of Epidemiology in the UCLA School of Public Health. Most people don't think about marijuana in relationship to cancer, said Dr Zhang. The carcinogens in marijuana are much stronger than those in tobacco. The big message here is that marijuana, like tobacco, can cause cancer, said Dr Zhang. He studied the relationship between marijuana use and head and neck cancers in 173 patients diagnosed with those diseases. He compared those findings to 176 cancer free control patients, and found that those who habitually smoked marijuana were at higher risk for head and neck cancers. The epidemiological data was collected by questioning patients about their histories of tobacco smoking, cannabis smoking and alcohol use. Dr Zhang said researchers were able to evaluate the data on marijuana smoking independently from data on tobacco smoking and alcohol use, which also increase the risk of certain cancers. The findings will come as a shock to those smoking cannabis since the 1960s because head and neck cancers -- cancers of the mouth, tongue, larynx and pharynx -- take a long time to develop. People who smoked large amounts of marijuana in the 1960s may just now be contracting head and neck cancers, Dr Zhang said, adding that cannabis smokers are 16 times more likely to develop these cancers than people who never smoked Ireland's most popular illegal drug. - --- MAP posted-by: allan wilkinson