Does smoking marijuana cause cancer? i had thyroid cancer and would like to know if related. no tobacco. can. it. cause throat cancer.

No relationship: Of thyroid cancer and smoking, but respiratory (lung, etc.) yes.

Probably not: I am not aware of any studies linking marijuana to most cancers. But - you are inhaling a caustic substance into the lungs that can cause damage with time. Furthermore - marijuana is sometimes cut with a variety of chemicals that may be carcinogenic. I would suspect that prolonged use may be associated with throat and lung cancer, but studies are conflicting [for the docs: eur resp j feb 2008].