Pubdate: Wed,  2 Jun 2004
Source: Seattle Times (WA)
Copyright: 2004 The Seattle Times Company
Author: Kyung M. Song
Bookmark: (Cannabis)


Recreational marijuana smokers are no more likely to develop oral
cancer than nonusers, a new study led by the Fred Hutchinson Cancer
Research Center says.

The latest findings contradict a 1999 California study that implicated
regular pot smoking as having markedly higher risks for head and neck

While not conclusive, the findings by "The Hutch," located in Seattle,
suggest that cancers of the mouth should rank low among the known
health hazards of marijuana use.

Oral cancer "probably shouldn't be one of the things people should
worry about when they decide whether to smoke marijuana," said Stephen
Schwartz, a member of Fred Hutchinson's public-health sciences
division and the study's senior author. "Our study found no
relationship between marijuana and cancer."

Marijuana is the nation's most commonly used illicit drug. Marijuana
smoke has some of the same carcinogenic properties as tobacco, but
researchers have yet to definitively establish that smoking marijuana
causes any types of cancer, Schwartz said. Tobacco is blamed for a
host of cancers, including lung, kidney, cervix, bladder and
pancreatic cancers.

Researchers more commonly recognize that marijuana can impair
cognitive abilities, such as memory, verbal IQ and driving. At the
same time, marijuana has been shown to have some beneficial
properties, including possibly boosting the body's immune system.

Schwartz said researchers were unable to find a correlation between
cancer and how much and how long a person has used marijuana. The
study involved 407 oral-cancer patients and 615 healthy control
subjects from Western Washington. Most of the study participants
smoked marijuana less than once a week. Only 1 percent of the cancer
patients and 2 percent of the control subjects were daily users.

Researchers from the University of Illinois, Urbana-Champaign and
Seattle's Group Health Cooperative collaborated on the study.

The study refutes earlier findings by researchers at the University of
California, Los Angeles, who concluded that the odds of getting head
and neck cancers rose in tandem with the frequency and duration of
marijuana use.

Schwartz contends the UCLA study's sample was too small and its
control group - drawn from blood donors who had passed a health
screening - did not accurately reflect the population at large.

Dr. Zuo-Feng Zhang of UCLA's Jonsson Cancer Center and one of the
authors of the earlier study, said he had not seen The Hutch's
findings and could not comment. But Zhang said The Hutch's study,
although involving a larger sample, still is only one study and that
there is no scientific consensus yet on any link between marijuana and

Zhang noted that many people who began smoking marijuana during the
1960s may just now be developing cancers of the tongue, mouth and
larynx. Zhang and his fellow researchers are conducting a larger, more
comprehensive follow-up to their 1999 study.

Schwartz warned that marijuana users should not take The Hutch's
findings as reassurance that marijuana is harmless, at least as far as
cancer is concerned. For one thing, marijuana's effects on
"uncommonly" heavy users still are largely unknown, he said.

"I don't think we've heard the last word on this issue," Schwartz said.
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MAP posted-by: Larry Seguin