...despite potentially higher levels of polycyclic aromatic hydrocarbons found in cannabis smoke compared to tobacco smoke (dependent on what part of the plant is smoked), the THC present in cannabis smoke should exert a protective effect against pro-carcinogens that require activation. In contrast, nicotine activates some CYP1A1 activities, thus potentially increasing the carcinogenic effects of tobacco smoke-
Cannabis and tobacco smoke are not equally carcinogenic
^^^Thanks, Granny!^^^

I remember that most of cannabis' carcinogens are NOT in the smoke-able part (the bud). Notice the parenthesis in the first sentence (of the quote, above).