NEW STUDY DISCOUNTS LINK BETWEEN ORAL CANCER, POT SMOKING

Previous Research Found A Correlation

Smoking marijuana does not increase the risk of developing oral
cancer, according to a new study from Seattle researchers that
contradicts an earlier study.

The previous study, led by researchers from the University of
California-Los Angeles in 1999, found that marijuana users were 2.5
times more likely to develop head and neck cancer, including tumors of
the larynx and throat, than non-users. Researchers suggested that baby
boomers who began smoking marijuana during the 1960s, when the drug
surged in popularity, could experience higher rates of head and neck
cancers as they age.

But the latest research finds no indication of an elevated risk, said
Stephen Schwartz, an epidemiologist at the Fred Hutchinson Cancer
Research Center and the new study's lead author. More than three times
the number of participants were included in the latest study,
improving the reliability of the findings, Schwartz said.

"If people are thinking about what might be happening to them in the
future because of marijuana use, oral cancer is not something you
should be particularly worried about," said Schwartz.

The study, published in the June issue of Cancer Research, the journal
of the American Association for Cancer Research, included 407 people
with oral cancer and 615 healthy adults between ages 18 and 65 from
King, Pierce and Snohomish counties, who were located using random
telephone surveys.

Participants were asked to describe their marijuana use between 1985
and 1995, including how often they smoked. About 25 percent of
participants in both groups said they had smoked marijuana at some
point in their lives.

Marijuana use has also been linked to lung cancer, with studies
indicating that marijuana smoke can cause molecular and cellular
changes in lung tissue that are consistent with the early stages of
cancer. Marijuana smokers inhale more deeply and hold the smoke in
their lungs longer than tobacco smokers, which may explain the high
levels of tar found in marijuana users' lungs. In addition, marijuana
cigarettes do not have filters.

An estimated 28,260 new cases of oral cancer will be diagnosed this
year nationwide, resulting in 7,200 deaths, according to the American
Cancer Society. Cigarette smoking, chewing tobacco and alcohol are all
known risk factors for oral cancer, which is found most commonly on
the tongue, but also appears on the lips, floor of the mouth and tonsils.

Because so few of the study participants said they were chronic,
long-term users, it's unclear whether frequent marijuana use could
lead to oral cancer, Schwartz said.

Dr. Zuo-Feng Zhang, an epidemiology professor at the Jonsson Cancer
Center at UCLA, led the 1999 study and is nearly finished with a
larger study involving about 2,400 people. His research, looking at
the connection between head, neck and lung cancer and marijuana use,
is funded by the National Institute on Drug Abuse.