Evaluation of Safety of Intralesional Cidofovir for Adjuvant Treatment of Recurrent Respiratory Papillomatosis.

Importance: The use of intralesional cidofovir injections for recurrent respiratory papillomatosis (RRP) remains controversial owing to concern regarding the risks of its use, including increased risk of dysplasia or carcinogenesis. Objective: To describe the rates of dysplasia, development of malignant lesions, and adverse events associated with use of intralesional cidofovir injections as adjuvant treatment for RRP compared with patients treated without adjuvant cidofovir. Design, Setting, and Participants: In this case series performed at a tertiary care referral center, review of electronic medical records on all adult and pediatric patients (N = 154) treated for RRP with adequate follow-up from January 1, 2000, to December 31, 2016, was performed. Data were collected on the use of cidofovir, development and presence of dysplasia or malignant lesions, complications, and intersurgical interval. Exposures: Adjuvant intralesional cidofovir or surgical excision only. Main Outcomes and Measures: The main outcomes measured were the development of dysplasia, malignant lesions, and complications from treatment. These outcomes were determined before collection of data. Results: Of the 154 patients included in the analysis, 83 patients (53.9%) received adjuvant intralesional cidofovir and 71 patients (46.1%) underwent surgical excision only. One hundred patients (64.9%) were male; mean age was 27.7 (95% CI, 24.3-31.2) years. Patients were followed up for a median (interquartile range) of 70 (24-118) months in the noncidofovir group and 91 (47-152) months in the cidofovir group. There were no statistically significant differences in the rates of development of dysplasia (2.8%; 95% CI, -8.3% to 13.2%) or malignant lesions (2.2%; 95% CI, -5.3% to 11.2%) between the groups. No nephrotoxic effects were observed in the treated cohort, and only 5 minor complications that occurred in 628 injections were noted in the cidofovir group; 3 were related to direct laryngoscopy and 2 were related to needle malfunction. Conclusions and Relevance: In this cohort of patients with RRP, adjuvant intralesional cidofovir injections did not appear to cause major complications or an increased rate of development of dysplasia and cancer.