Smoking and alcohol use have generally been considered the primary causative agents in head and neck cancer, but the growing incidence of the tumors over the last two decades is attributed to another source -- human papillomavirus, or HPV, especially HPV-16, which is a key player in cervical cancer and one of the targets of the two commercial HPV vaccines. Tumors linked solely to HPV appear to be easier to treat than those associated with smoking, and a new study shows that smokers who have an HPV-linked tumor are six times as likely to have a recurrence as those who have never smoked.
Head and neck squamous cell carcinomas are the eighth most common malignancy worldwide, accounting for about 5% of all diagnoses. In the United States, about 35,720 people will be diagnosed with the tumors this year and about 7,600 will die from them, according to the American Cancer Society. Current treatments include radiation, chemotherapy and surgery, and side effects from the treatment regimen can be harsh.
To study the relationship between HPVs and smoking, otolaryngologist Thomas Carey of the University of Michigan Comprehensive Cancer Center and his colleagues studied 124 patients with advanced cancer of the tonsils or the base of the tongue. About two-thirds of the 102 patients with HPV-linked tumors were current or former tobacco users, while all 22 of those who were HPV-negative were smokers. The researchers reported Monday in the journal Clinical Cancer Research that, among those with HPV-linked tumors, about 6% of those who never smoked had a recurrence, compared to 19% of those who had smoked in the past and 35% of those who were current smokers. Among the smokers with tumors not linked to HPV, half suffered a recurrence. The time to recurrence was also significantly shorter in those who did not have HPV-linked tumors, as was overall survival.
The team's original goal, Carey said, was to determine whether those who did not smoke had a better prognosis and thus might be able to be treated with a less harsh regimen. The results suggest that is the case, and they will begin a clinical trial of milder treatment this spring.
-- Thomas H. Maugh II