Objectives: Determine the exact incidence of pulmonary involvement in recurrent respiratory papillomatosis (RRP); explore available treatments and their effectiveness; determine the characteristics of cases that progress to lung cancer.
Data sources: MEDLINE, EMBASE, and the Cochrane Library databases between 1966 and 2007; reference lists of retrieved publication.
Study selection: Studies investigating recurrent respiratory papillomatosis with lung involvement. Age limited to 20 years of age to qualify for the diagnosis of juvenile-onset RRP.
Data extraction: Data pertaining to study design, population demographics, risk factors, site of involvement, investigation including the determination of the human papillomavirus type, treatment, and outcomes including the development of cancer.
Data synthesis: No randomized control trials were retrieved. Hundred and one studies met our inclusion criteria (23 cohorts, 4 case series, 72 case reports, 2 open trials) with 161 cases of lung involvement identified. From the cohort studies we could estimate the incidence of lung involvement in RRP at 3.3%. The incidence of cancer in cases with lung involvement was 16%. We could not draw conclusions regarding treatment effectiveness in lung involvement, as that was not evaluated except in case studies. It would nevertheless appear that Interferon is not effective and the use of intravenous Cidofovir needs to be better evaluated.
Conclusion: Well-designed, hypothesis-driven randomized control trials and prospective cohort studies are warranted to improve our understanding of the mechanisms underlying the development of lung involvement in RRP, the risks associated with different HPV types, the efficacy of potential therapeutic options as well as the risk of progression to cancer.