Tobacco smoking is a well-known risk factor in human papilloma virus (HPV)-negative head and neck squamous cell cancer. Its effects include increased risk of treatment failure, distant metastases and reduced overall survival. HPV has been increasingly implicated as a causative factor in the development of oropharyngeal cancer (OPSCC), a distinct entity with a more favourable outcome in comparison to HPV-negative disease. The impact of active smoking on survival in HPV+ OPSCC remains unclear. Understanding the association between active smoking status and outcomes is critical for risk stratification when treating this group of patients. Xiao et al retrospectively assessed the smoking status of 484 HPV+ OPSCC patients treated in a single institution over a 14-year period. Patients were categorised as never, former or active smokers. Active smokers were those who quit within three months of diagnosis or continued to smoke during and or after treatment. Former smokers were defined as those who quit more than three months prior to diagnosis. Quantification of pack years were also captured. The primary end point was overall survival (OS) with progression free survival (PFS) noted as a secondary outcome.
This study found that active smoking at diagnosis represented a significant risk factor for inferior OS and PFS as well as distant metastasis. The majority were treated non-surgically with no significant difference between treatment groups.
Active smokers were more likely to have a significantly higher T stage (T3 24.5% vs. 17.2% for former/never smokers and T4 22.3% vs. 10.5%) at diagnosis and twice as likely to have stage III disease at diagnosis. This study also adds to the evidence base that suggests that a greater than 20 pack year history predicts poor outcome. The results are clinically meaningful in everyday practice as it suggests smoking cessation is a modifiable risk factor in improving treatment outcome.