From what I understand from listening to oral surgeons and ENTs, it's that alcohol is an irritant, so I suppose if one only irritates occasionally, it might be OK.  
However, presuming my cancer came from tobacco or alcohol, I had abstained from them for 35 and 11 years respectively before the cancer came out, so it's apparently a delayed effect.  If it was 
HPV, that was only a 10 year abstinence.  Yet, there was only about 2.5 years between my irradiation and a second recurrence in the irradiated zone.
I know more than I understand about this disease.