Background
Testicular germ cell tumours (TGCTs) are the most common neoplasm of males aged 15 to 45 years. The incidence of TGCT has increased steadily in recent decades suggesting a change in non-genetic risk factors, but the exact causes of TGCT remain elusive.
Germ cell function may be influenced by cannabinoids, and two prior epidemiologic studies have reported that the use of marijuana may be associated with nonseminomatous TGCT.
This study provides more data to explore this reported association.
Aim
To evaluate the relation between TGCTs and exposure to marijuana and other recreational drugs using a population-based case-control study.
Methods
In total, 163 patients who were diagnosed with TGCT in Los Angeles County from December 1986 to April 1991 (81% of eligible cases) were enrolled, and 292 controls (79% of eligible controls) were matched on age, race/ethnicity, and neighbourhood.
Participants were asked about drug use by a structured, in-person interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression analysis adjusted for history of cryptorchidism; education; religiosity; and reported use of marijuana, cocaine, and amyl nitrite.
Results
Compared with never use, ever use of marijuana had a 2-fold increased risk (OR, 1.94; 95% CI, 1.02-3.68), whereas ever use of cocaine had a negative (inverse) association with TGCT (OR, 0.54; 95% CI, 0.32-0.91).
Stratification by tumour histology revealed a specific association of marijuana use with nonseminoma and mixed histology tumours (OR, 2.42; 95% CI, 1.08-5.42) but not with seminomas (OR, 1.07; 95% CI, 0.37-3.07).
Conclusion
A specific association was observed between marijuana use and the risk of nonseminoma and mixed tumours. To the authors’ knowledge, this is the first report of a negative (inverse) association between cocaine use and TGCT risk.
The current results warrant mechanistic studies of marijuana’s effect on the endocannabinoid system and TGCT risk and caution that recreational and therapeutic use of cannabinoids by young men may confer malignant potential to testicular germ cells.
