Prognostic Influence of Tobacco Smoking on Human Papilloma Virus-Related Oropharyngeal Cancer is Dependent Upon Treatment Modality

Abstract [Purpose] Tobacco smoking has been reported to influence the prognosis of human papilloma virus (HPV)-related orophageyngeal squamous cell carcinoma (OPSCC). However, it remains to be studied whether tobacco smoking equally affects the patients treated by various modalities. [Material and Method] From 2010 through 2018, 241 patients with OPSCC were treated in a single institution, out of which 144 patients had HPV-related OPSCC. P16 immunohistochemical staining was used as a surrogate of HPV infection. Two patients was excluded because of inadequate radiation dose, and the remaining 142 patients were the subject of this study. Median age was 63.8 years and more than 80% were male. More than 70% were smokers or ex-smokers with a median pack year of 17.3. Eighty-seven patients (61.3%) were classified as stage I.[Results] For all 142 patients with HPV-related OPSCC, overall survival (OS) and disease-specific survival (DSS) were 87.0% and 93.4% in 3 years, respectively. There were no differences of OS and DSS according to the stages by 8th edition of tumor, node, and metastasis (TNM) classification and the primary sites. OS and DSS were different by the amount of tobacco smoking expressed in pack year (PY) > 30 and < 30. Also the presence of secondary cancer impacted OS. However, the influence of the amount of tobacco smoking was reduced in the patients treated by radiation therapy. [Conclusions] The impact of tobacco smoking upon the prognosis of HPV-related OPSCC seems to be dependent upon therapeutic modalities.