Researchers examined the molecular characteristics of OPSCC caused by HPV in an effort to determine which DNA mutations predict lower disease free and survival rates among HPV-positive throat cancer patients who smoke. Whereas most patients with OPSCC caused by HPV have an excellent prognosis for disease free survival, those who also smoke generally face more dire prognoses.
The 66 cases of HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) in this study were split into heavy and light smoking behavior groups based on pack years. This metric of smoking frequency over long stretches of time is determined by multiplying the number of years a person has smoked by their average number of packs of cigarettes smoked per day. Forty of the 66 patients reported more than 10 pack years (e.g., more than one pack per day for 10 years or two packs per day for five years), and 26 patients reported fewer than 10 pack years.