Weed Worries
A good rule to follow in medicine when evaluating whether research should be translated into clinical care is “reproducibility.” Good research, that is research that is likely to end up as “true fact” in the long run, is reproducible…not just by the original researchers, but also (and more importantly) by others in the field. In med speak, where the number of syllables matters greatly, we call this “independent confirmation.”
The legalization of pot has been in the news quite a bit lately, especially in California. So has interesting research linking pot use to testis cancer. I have been tracking this research since 2009 when a study first associated pot use with higher testis cancer rates. Clinically, it suggests that pot use is a “risk factor” for testis cancer. Normally, I’m wary of making conclusions based off a single study, but when subsequent research made similar findings… now that gets my attention!
Testis cancer is the most common cancer in young men ages 15-35. Of real concern is that the rates of testis cancer are rising 3-6% annually since the 1970s in the US and even faster in Europe. It is usually caught early and is highly curable, but it should be avoided at all costs. It brings along with it other multi-syllable words like “orchiectomy” (testis removal), “chemotherapy,” “radiotherapy,” “infertility,” and “hypogonadism” (low testosterone), which are all as ugly as they sound. Currently, there are few known risk factors for testis cancer except a history of an undescended testicle or other condition resulting in abnormal testis development, a family member with testis cancer, being Caucasian, and possibly infertility. Sooner rather than later, we may need to add chronic or frequent pot use to the list.
How much pot is risky? Both studies showed that long-term pot use (greater than 10 years or since adolescence) and greater than once weekly users had twice the rate of testis cancer as nonusers. In the most recent study, daily marijuana use tripled the risk of testis cancer. And the strength of these links held strong when other lifestyle issues such as alcohol and tobacco use were considered.
How does pot increase the risk of testis cancer? Not clear really, , which can alter testosterone balance. Both of these can unfavorably alter the testis environment in a critical way.
The evidence has only gained more corroboration since I first posted on this subject. A few years ago, the Journal of the American Medical Association posted a meta-analysis of 25 studies that examine a link between marijuana use and cancer. The only form of cancer that had a significant (but not major) elevated risk was testis cancer. The risk was strongest for marijuana smokers who have used the drug for many years. It is still not clear why smoking pot affects the testis in this way, but it is worth knowing as you make decisions about your own health.
At this point, being the preventative doctor that I am, I recommend stashing the sweet Lucy, junking the joint, cutting the grass, pitching the pot, winging the weed, burying the bammy and heaving the hemp. It’s just not worth it.
