Victoria Cortessis, Ph.D. / photo by Van Urfalian
By USC Health Sciences Public Relations & Marketing Staff
A new study from the University of Southern California (USC)
has found a link between recreational marijuana use and an increased
risk of developing subtypes of testicular cancer that tend to carry a
somewhat worse prognosis.
Published early online in Cancer,
a peer-reviewed journal of the
American Cancer Society, the findings suggest that the potential
cancer-causing effects of marijuana on testicular cells should be
considered not only in personal decisions regarding recreational drug
use, but also when marijuana and its derivatives are used for
therapeutic purposes in young male patients.
Testicular cancer is the most common cancer diagnosed in young men ages
15 to 45 years. The malignancy is becoming more common, and researchers
suspect this is due to increasing exposure to unrecognized
environmental causes.
To see if recreational drug use might play a role, Victoria Cortessis,
MSPH, Ph.D., assistant professor of preventive medicine at the Keck
School of Medicine of USC in Los Angeles, and her colleagues looked at
the self-reported history of recreational drug use in 163 young men
diagnosed with testicular cancer and compared it with that of 292
healthy men of the same age and race/ethnicity.
The investigators found that men with a history of using marijuana were
twice as likely to have subtypes of testicular cancer called
non-seminoma and mixed germ cell tumors. These tumors usually occur in
younger men and carry a somewhat worse prognosis than the seminoma
subtype. The study’s findings confirm those from two previous reports
in Cancer on a potential link between marijuana use and testicular
cancer.
“We do not know what marijuana triggers in the testis that may lead to
carcinogenesis, although we speculate that it may be acting through the
endocannabinoid system—the cellular network that responds to the active
ingredient in marijuana—since this system has been shown to be
important in the formation of sperm,” said Cortessis.
The researchers also discovered that men with a history of using
cocaine had a reduced risk of both subtypes of testicular cancer. This
finding suggests that men with testicular cancer are not simply more
willing to report a history of using recreational drugs. While it is
unknown how cocaine may influence testicular cancer risk, the authors
suspect that the drug may kill sperm-producing germ cells since it has
this effect on experimental animals.
“If this is correct, then ‘prevention’ would come at a high price,”
Cortessis said. “Although germ cells can not develop cancer if they are
first destroyed, fertility would also be impaired. Since this is the
first study in which an association between cocaine use and lower
testis cancer risk is noted, additional epidemiological studies are
needed to validate the results.”
The study was supported by grants from the National Cancer Institute,
including CA136967
and CA102042.