As more and more states legalize medical and/or recreational marijuana, concerns about health risks continue to grow. Now, a new study, aimed at defining the association between regular marijuana use and cancer risk, suggests that men who regularly smoke marijuana do have a slightly increased risk of developing testicular cancer.
The study’s findings, however, published in the Journal of the American Medical Association, note that more research is needed to understand exactly what role marijuana plays in cancer development.
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“We don’t know the impact of other forms of use — e.g. vaping, edibles, etc. — or of newer formulations,” Dr. Korenstein says.
There also remains the question of how much marijuana is safe to use to avoid this increase in testicular cancer risk. The research, which looked at data from 25 studies that varied in size, concluded that men who smoked an average of one joint a day for more than 10 years had an increased risk of developing testicular cancer. The risk could be much greater for people who average more than the equivalent of one joint a day.
“That’s a concern since with legalized recreational use, people might consume more than in the past,” Dr. Korenstein adds.
Results were inconclusive for other cancers researchers looked at, such as head and neck squamous cell carcinoma and oral cancer. Findings on lung cancer were mixed because of limited information on people who only smoked marijuana. Many people who were looked at in the studies smoked both cigarettes and marijuana, making it difficult to associate any risk with marijuana specifically.
“Marijuana users tend to smoke less than cigarette smokers, so it may be that heavy marijuana smoking does cause lung cancer, but that very few people smoke enough to actually increase their risk,” Dr. Korenstein said.
What We Know about Marijuana and Cancer
A big issue with the increasing popularity of marijuana use, according to the new study and several experts SurvivorNet has interviewed in the past, is that doctors can’t say for sure how dangerous it is. While medical marijuana has provided great relief to many people dealing with the side effects of cancer treatment, when it comes to dangers associated with pot, there simply isn’t enough data for any clear warning at this time.
“What’s sad in medicine is that we have to wait for the bad event to happen before we can intervene,” Dr. Raja Flores, head of thoracic surgery for the Mount Sinai Health System, told SurvivorNet in a previous interview. “As someone in the front lines who sees this everyday, I’ve seen lung cancer caused by marijuana that is incredibly aggressive. Just because we don’t have the numbers yet, because we haven’t been recording this data, doesn’t mean that marijuana is safe.”
Dr. Raja Flores tells SurvivorNet that we, as a country, may be underestimating the dangers associated with smoking pot.
Dr. Flores pointed to the lack of a thorough, population-based study on the dangers of marijuana for a significant enough amount of time. He said that because we don’t have these statistics yet, the idea that marijuana is a safer alternative to drinking alcohol or smoking cigarettes is generally accepted by a lot of people.
“There is a lobby out there that is trying to say that marijuana is better than drinking, that it’s safer, that it doesn’t cause cancer, and that you should do that … and they’re both bad,” he said, adding that the popularity (and retail value) of marijuana may make users and businesses alike turn away from the potential risks.
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