High incidence of malignant transformation of laryngeal papilloma in Taiwan.

OBJECTIVES: Papillomas of the larynx include solitary laryngeal papilloma and recurrent respiratory papillomatosis. This study investigated the incidence of malignant transformation and assessed possible risk factors for laryngeal papillomas.

STUDY DESIGN: A prospective, longitudinal study.

METHODS: Twenty-six consecutive laryngeal papilloma patients were prospectively studied for 5 or more years, and each patient was periodically examined at 3 to 6 month intervals. A detailed epidemiologic questionnaire was administered at the initial visit. After enrollment, tissue obtained during each laryngeal surgery was examined by polymerase chain reaction assay for human papilloma virus (HPV) and typing.

RESULTS: During 237 person-years of follow-up, six new, pathologically confirmed cases of laryngeal carcinoma were ascertained (incidence 2.5/100 person-years), and all were associated with HPV-6 or HPV-11. Malignant transformation revealed no correlation with the following: age less than 3 years at diagnosis, sex, history of tobacco use, history of alcohol consumption, family history of laryngeal cancer, or type of laryngeal papilloma. Laryngeal papilloma without demonstrable HPV DNA was the only significant risk factor for malignant transformation (P < .05). The cumulative risk of malignant transformation in subjects without demonstrable HPV DNA was significantly higher than that in HPV-positive patients (relative risk, 8.0; 95% confidence interval, 1.1-60.3; P = .05).

CONCLUSIONS: A relatively high incidence of malignant transformation of laryngeal papilloma was noted in Taiwanese patients. Patients without demonstrable HPV DNA require more frequent follow-up and may benefit from anti-HPV vaccinations.