If this is right — and I have no idea whether it is, although the authors have respectable affiliations and it’s published in a very respectable journal — Rick Doblin is going to be completely insufferable.
All the studies of cannabis and lung cancer have come out negative, despite the presence of carcinogenic “tars” in cannabis smoke. Could this be a case of offsetting effects? And if so, would a close look show lower levels of non-respiratory-system cancers among heavy cannabis smokers? That shouldn’t be a hard study to do.
Footnote Someone should tell the authors that if you’re going to publish a paper that every non-specialist will quote as “pot kills tumor cells,” you should try to avoid a publication date of April 1.