STUDY FINDS LINK BETWEEN MARIJUANA, TESTICULAR CANCER

Young men who began using marijuana as adolescents or who smoke pot
at least once a week appear to be twice as likely to develop
testicular cancer as those who never used the drug.

The association, as reported by researchers at the Fred Hutchinson
Cancer Research Center in Seattle, was strongest with nonseminoma, an
aggressive, fast-growing subtype of testicular cancer that typically
strikes men between ages 20 and 35.

"It's not just that you develop testicular cancer, but you develop a
worse type of testicular cancer," said Dr. Glen Justice, director of
the cancer center at Orange Coast Memorial Medical Center in Fountain
Valley, Calif., who was not involved with the study.

About 40 percent of testicular cancers are nonseminomas. The rest are
slower-growing seminomas, which tend to occur a decade or two later,
when men are in their 30s and 40s. Since the 1950s, both kinds have
increased by 3 percent to 6 percent a year in the United States,
Europe, Australia and New Zealand.

Various studies have looked for environmental or lifestyle changes
that could account for the increase. The study published online
Monday in the journal Cancer was the first to look at marijuana.

Researchers interviewed 371 men ages 18 to 44 who had been diagnosed
with testicular cancer. They interviewed an additional 979 men of the
same age group and from the same three Washington counties who did
not have cancer.

The researchers found a 70 percent higher risk of testicular cancer
in those who were using pot at the time of diagnosis, with an even
higher risk associated with younger age at first use and frequency of
use. Hormonal changes during puberty are thought to make that a
particularly vulnerable period for environmental influences.

The findings were independent of known risk factors, such as
undescended testes and a family history of testicular cancer, and
adjusted for smoking and alcohol use.

The senior author of the study, epidemiologist Janet R. Daling, got
the idea to look at marijuana after learning that the testes, like
the brain, have receptors for tetrahydrocannabinol, or THC, the
chemical component of the marijuana high.