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Research Summary

Marijuana Associated with Testicular Cancer

Testicular cancer, generally classified as seminomatous (60%) and nonseminomatous (40%) with nonseminomatous being more aggressive and treatment resistant, is the most common cancer among American men ages 15 to 24 years, and its incidence has been increasing 3–6% per year over several decades. Prior research has demonstrated that chronic marijuana use impacts endogenous hormone levels in the endocrine and male reproductive systems. Researchers conducted a population-based case control trial to determine whether marijuana use is a risk factor for testicular cancer. Between 1999 and 2006, 369 cases of testicular cancer in men ages 18 to 44 years were identified from 3 counties in Washington State. These men, along with 979 age-matched controls, were surveyed about their lifetime marijuana use. Potential confounders in analytic models included age, alcohol use, current smoking, and history of cryptorchidism.

  • Patients with testicular cancer were 1.7 times more likely to be current marijuana smokers than controls.
  • This association occurred most frequently in patients with nonseminomatous tumors, who were 2.3 times more likely to be current marijuana smokers than controls.
  • Patients with nonseminomatous tumors were also more likely to have started using marijuana at an earlier age (odds ratio [OR], 2.8), to have been using marijuana for 10 or more years (OR, 2.7), and to have a higher frequency of use (OR, 3.0).


Marijuana use at an earlier age, for more years, and with higher frequency is associated with nonseminomatous testicular cancer. Prospective studies controlling for confounders as well as basic scientific research to elucidate the potential biologic mechanisms behind this association are needed to determine whether marijuana use causes nonseminomatous testicular cancer. Alexander Y. Walley, MD, MSc


Daling JR, Doody DR, Sun X, et al. Association of marijuana use and the incidence of testicular germ cell tumors. Cancer. 2009;115(6):1215–1223.