Improved Outcome with using a Pulsed-Dye Laser and Local Injection of Cidofovir for the Treatment of Recurrent Respiratory Papillomatosis

Introduction Although it's benign nature, recurrent respiratory papillomatosis (RRP) has difficulties in medical cure due to its clinical symptoms and frequent recurrence. Laser ablation under laryngomicrosurgery has been the treatment of choice up to now, however, several other additional treatment modalities are attempted. On this study, cidofovir, a nucleoside analogue which inhibits the viral DNA replication, was injected intralesionally after primary excision of RRP using CO2 laser and/or pulsed dye laser (PDL), and its efficacy was evaluated. Method and Materials Thirtyseven patients of laryngeal papilloma from age of 4 to 68 were selected from July 2006 to August 2008, and after the lesion was removed using CO2 LASER or PDL, diluted cidofovir (7.5 mg/ml initially, increased to 15 mg/ml from February 2008) was injected intralesionally from 2 to 4 ml. After the first cidofovir injection, planned second injection was done 2-8 weeks afterwards (mean interval : 3.3 week). Patients were followed up regularly on outpatient basis, and additional procedure was done according to the extent of recurred lesion. The severity score was measured using Derkay grade system on OPD basis, and when score 0 maintained more than 6 months, we defined it as complete remission. The ones, who reached 0, but recurred, classified as recur cases, and the ones who not reach score 0 were classified as therapeutic resistant cases. Result The average follow up term after first cidofovir injection is 15 months and 11 out of 26 presented with complete remission (42.4%). There were 8 recur cases (30.7%) and 7 therapeutic resistant cases (26.9%). In the case of juvenile-onset type RRP, 5 out of 12 showed complete remission, and 6 out of 14 showed complete remission in the case of adult-onset type RRP. When the interval between surgical procedures before and after cidofovir injection was compared, the interval demonstrated a tendency to increase after the injection. Conclusion Removal of lesion using CO2 laser and/or PDL and topical injection of cidofovir, seem to be effective for the treatment of RRP. The interval between surgical procedures increased even in recurrent cases and some patients maintained complete remission. Further studies with larger subjects and long-term follow-up are necessary.restrictio