Incidence, age at onset, and potential reasons of malignant transformation in recurrent respiratory papillomatosis patients: 20 years experience.

Forty-two patients with recurrent respiratory papillomatosis (RRP) were accepted into a multicenter prospective study in 1983 to 1990, treated with alfa-IFN 3 MU/m 2 3 times a week and then followed-up until August 1, 2003. All the patients who had disease progression with pulmonary spread were characterized by insufficient response to IFN-therapy and detection of HPV type 11. Five patients (4/5 smokers) presented malignant transformation in lungs or nasopharynx (mean RRP duration was 27.2 +/- 8 years from RRP onset and 14.6 +/- 6.3 years from pulmonary spread until malignant transformation) with persistent RRP in larynx. The results of long-term follow-up in RRP patients with HPV 11 underline the necessity of reanalyzing the current therapy.