Recurrent respiratory papillomatosis in adults with lower respiratory tract involvement: a retrospective study of the OrphaLung and GETIF networks.

Background: Recurrent respiratory papillomatosis (RRP) is a rare respiratory disease primarily caused by chronic human papillomavirus (HPV) infection of serotypes 6 and 11. It manifests in childhood (juvenile-onset recurrent respiratory papillomatosis (JoRRP)) and adulthood (adult-onset recurrent respiratory papillomatosis (AoRRP)), leading to progressive obstruction by papillomas in the upper airway and occasionally in the lower respiratory tract (LRT), including the lungs, with a potential for malignant transformation. This study aimed to delineate the characteristics of JoRRP and AoRRP with LRT involvement in adulthood.

Methods: A multicentre French-speaking cohort study was conducted, coupled with a comprehensive literature review of clinical, histological, therapeutic and prognostic features associated with RRP with LRT involvement.

Results: Among the 122 cases of RRP with LRT involvement analysed, 55 (45%) had JoRRP and 67 (55%) had AoRRP. The mean age at diagnosis was 4 years for JoRRP and 54 years for AoRRP. Ear, nose and throat involvement was observed in all JoRRP cases and in 34 AoRRP cases (51%). Lung involvement occurred in 47 JoRRP cases (85%) and in 10 AoRRP cases (15%). Malignant transformation to squamous cell carcinoma in the trachea (n=6) or lung (n=36) was observed in 42 patients (34%). Factors associated with lung involvement included JoRRP, repeated debulking and malignant transformation; the only factor associated with malignant transformation was lung involvement. Overall mortality was 16%, with JoRRP, lung involvement and malignant transformation identified as risk factors for death.

Conclusion: This study highlights the prevalence of lung involvement and malignant transformation in RRP with LRT involvement and advocates for targeted screening measures and preventive therapeutic strategies.