I never heard it caused lung cancer. I did read recently of a study that found brain function is reduced in teens and young adults who engage in regular pot smoking - permanently. That means brain damage.
Pot should never be confused with ciggs. in the minds of users. Pot is brain and mind altering and ciggs are not. Adults should not represent pot to young people as being harmless for them. Anyone who needs quick reactions (driving), focus (driving) and high brain function (work), should consider only recreational pot use.
I am sure you know that some pot is more potent than others and it’s important to know what you are doing to measure the degree of handicap you are dealing with.