I am not aware of any doctors that would recommend using methadone permanently and and it is only legally available to be prescribed for ongoing substitution therapy by federally certified abuse recovery centers. So my analogy still stands. No one should be actively campaigning to grow the methadone market the way that people are for e-cigarettes.
As far as I remember you are getting cancer, although at a lower risk, at least accordingly to some study posted here in the past that I can’t pinpoint right now.