Each of us is biologically unique. While you consider 2 packs a week to just be a "social smoker", in the right person those 400 carcinogens found in tobacco at that level would be enough to cause a malignancy. Doctors seldom like to tell people that their lifestyle choices may have lead them to a particular disease, because it only adds more emotional pain to the situation as the patient beats themselves up emotionally for something that they can't go back and undo. So the anseer to your question is ALL smokers are putting themselves at risk, regardless of any subjective feeling that it was light, moderate or heavy. HPV 16/18 viruses can be a cofactor and a facilataor, as well as a causative agent in their own right. This is something that has accounted for the great increase in young non smoking oral cancer patients in the last decade.

It is obviously important that regardless of the negative PET's, which are not conclusive diagnostic mechanisms, that you should be in the hands of a GROUP of doctors of different diciplines (radiation, chemo, and surgery) at a major center that will treat the patient appropriately regardless of the ability to locate a finite primary.

Just a small correction, Salagen will not PROTECT salivary function, and only aid in the producton of saliva in some post treatment patients who have compromised salivary function from their radiation treatments.

I agree that cervical mets are seldom primary locations, and an occult primary does indeed exist somewhere else.