title: Time course of juvenile onset recurrent respiratory papillomatosis caused by human papillomavirus.
abstract: BACKGROUND
  With the recent licensure of a new quadrivalent vaccine, many diseases caused by human papillomavirus (HPV) can now be prevented, including recurrent respiratory papillomatosis (RRP). The purpose of this study was to describe the burden and time course of juvenile onset RRP.
  
  
  METHODS
  A retrospective chart review was conducted of children with airway papillomatosis at the Hospital for Sick Children in Toronto, Canada, between 1994 and 2004. Statistical methods included descriptive statistics of the cohort, a repeated events survival model, and nonlinear modeling equations to describe the time course of illness.
  
  
  RESULTS
  Nine hundred twenty-six surgical procedures in 67 patients were identified through a review of surgical records. The median age at diagnosis was 3.2 years (range, 0.1-14.8 years) and the most common presenting symptom was hoarseness (75%). Adjuvant pharmacologic therapy (interferon or cidofovir) was used in 13 cases (19%). HPV types 6 or 11 were identified most commonly as the etiologic agent. Nonlinear modeling equations (exponential and quadratic) fit the observed data well, and were superior to linear models. Repeated events survival analysis identified significant prognostic variables: surgeon, adjuvant therapy, and anatomic score. A decision rule is presented that allows the time to next surgery to be predicted based on the previous surgery and the anatomic score.
  
  
  CONCLUSIONS
  Most patients have a decelerating rate of debulking surgeries over time, well described by our nonlinear modeling equations. Factors affecting the time course of RRP include: inter-surgeon variability, the extent and severity of papillomas at the time of laryngoscopy, and the use of adjuvant medical therapies.
authors.affiliation: Division of Infectious Diseases, Hospital for Sick Children, Toronto, ON, Canada. michael.hawkes@utoronto.ca
authors.forename: Michael
authors.initials: M
authors.lastname: Hawkes
authors.forename: Paolo
authors.initials: P
authors.lastname: Campisi
authors.forename: Rubeena
authors.initials: R
authors.lastname: Zafar
authors.forename: Xerxes
authors.initials: X
authors.lastname: Punthakee
authors.forename: Annie
authors.initials: A
authors.lastname: Dupuis
authors.forename: Vito
authors.initials: V
authors.lastname: Forte
authors.forename: Elizabeth Lee
authors.initials: EL
authors.lastname: Ford-Jones
mesh_terms: D000293:Adolescent; D052685:Alphapapillomavirus; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D030361:Papillomavirus Infections / Q000473:pathology* / Q000601:surgery; D012141:Respiratory Tract Infections / Q000601:surgery / Q000821:virology*; D012189:Retrospective Studies; D013997:Time Factors