Victoria Cortessis, PhD, Norris Comprehensive Cancer Center and departments of Preventive Medicine and Obstetrics and Gynaecology at the Keck School of Medicine of the University of Southern California, recently made the link between testicular cancer and the use of marijuana.
What is testicular cancer?
Testicular cancer occurs when a set of malignancies that are the result of germ cells in the testicles where sperm production occurs. It occurs most commonly in young men between the ages of 15 to 35.
Luckily, most young men who are diagnosed with testicular cancer do respond extremely well to the cancer treatment and the majority are eventually cured of their cancer. However, most are young and they land up living with an increased risk of infertility, heart disease, sexual problems, and other cancer.
Environmental causes of testicular cancer
Researchers are looking to the environment for causes of testicular cancer. Dr. Leslie Bernstein designed and then ran a study where she looked at the role of recreational drugs as a cause for testicular cancer.
Previous known factors that increase the risk of testicular cancer
- A personal history of congenitally undescended testicles increases the risk of testicular cancer by four times.
- Family history of testicular cancer is also associated with an increased risk
- Genetic variants have recently been identified as playing a role in the development of testicular cancer.
- Some environmental factors can increase a man’s risk of testicular cancer.
- Organchloride pesticides have been linked to an increased risk of testicular cancer.
Recent research showed link between recreational use of marijuana and an increased risk of testicular cancer
This study  referred to the use of marijuana recreationally, and has no implication for the use of marijuana for medical care.
The study showed almost all of the increased risk was related to non-seminoma, which is a type of testicular cancer that generally occurs at earlier ages and requires a much more aggressive treatment.
All studies that have looked at the association between marijuana use and testicular cancer have found the same results. It is highly unlikely that these findings are the result of chance, because of the statistical properties of the estimates from each study, and the consistency of the results between studies.
However, there does remain the possibility that men who use marijuana are strongly inclined to have some risk factor that has not yet been discovered, and therefore not measured in these studies. However, that risk factor would have to be even stronger than the effect of marijuana, and so far, no such risk has been identified.
What mechanism causes the use of recreational marijuana to lead to testicular cancer?
The research  indicates there may be two scenarios that result in the risk of testicular cancer increasing after the use of marijuana.
- The use of marijuana could interfere with hormonal signaling that is needed for the correct development and function of the testicle. In studies involving animals, controlled experiments were conducted where both marijuana smoke and the marijuana constituent THC showed suppressed androgen levels in male mice. Likewise, in men who smoke marijuana researchers have also found them to have a have lower levels of androgens circulating in their blood. Therefore, it is speculated that perhaps elevated risk of seminoma occurs, as a result, of marijuana’s suppression of androgens below levels required by the testicles for optimal health.
- THC from marijuana interferes with other biological processes, which are carried out by the so-called Endocannabinoid system. This network of signaling molecules produced by the body bind the same cellular receptors as THC. These receptors are found in testicular tissue, and it has speculated that THC from marijuana could bind these receptors, causing them to be unable to carrying out their usual function and therefore damaging testicles in a way that predisposes to non-seminoma. It was this speculation that led Dr. Janet Daling to investigate the risk of marijuana use as a possible contributor to testicular cancer.
There will be further research relating to recreational use of marijuana and testicular cancer. The work discussed above can be accessed online at http://onlinelibrary.wiley.com/doi/10.1002/cncr.27554/abstract
So what does this mean to young men who like to smoke marijuana? Well it means they might want to rethink their use for yet another reason. What does it mean for government and enforcement against the use of marijuana? Whether you agree with the legalization or not of marijuana, this would indicate this is yet another reason why it is unlikely that we will see marijuana legalized anytime soon. After all, like cigarettes, it is the health risks that are of greatest concerns when it comes to the use of marijuana, not ones moral beliefs.
2) The Online Library http://onlinelibrary.wiley.com/doi/10.1002/cncr.27554/abstract