"We found that moderate marijuana use was significantly associated with reduced risk of HNSCC [head and neck squamous cell carcinoma]. This association was consistent across different measures of marijuana use (marijuana use status, duration, and frequency of use). Diminished risk of HNSCC did not differ across tumor sites, or by HPV [human papillomavirus] 16 antibody status. Further, we observed that marijuana use modified the interaction between alcohol and cigarette smoking, resulting in a decreased HNSCC risk among moderate smokers and light drinkers, and attenuated risk among the heaviest smokers and drinkers."


Liang, Caihua; McClean, Michael D., et al., "A Population-Based Case-Control Study of Marijuana Use and Head and Neck Squamous Cell Carcinoma," Cancer Research Prevention (New Milford, CT: American Association for Cancer Research, August 2009), p. 766.