Marijuana use is associated with an increase in risk of testicular cancer, new study says.

The study involved approximately 163 young men diagnosed with testicular disease. Their medical data along with self-reported use of marijuana were compared to medical data of 292 healthy men.

Testicular cancer affects men between the ages of 15 and 35. There are two main subtypes of this cancer, called seminoma or non-seminoma. 

Researchers found marijuana users at high risk of developing non-seminoma testicular cancer and mixed germ cell tumors. These subtypes are considered more dangerous, high rates of fatality, than other subtypes of testicular cancer like the seminoma subtype.

"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 Victoria Cortessis, PhD, assistant professor of preventive medicine at the Keck School of Medicine of USC in Los Angeles.

Cocaine

The research found that cocaine reduces risk for both the sub-types of cancers. People who used cocaine had lower risks of both the subtypes of testicular cancer. However, researchers say that because the drug kills of the cells that make sperm, fertility may also be affected in men who abuse cocaine.

"If this is correct, then 'prevention' would come at a high price. 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," Cortessis said.

The study was published in the journal Cancer.