Recurrent respiratory papillomatosis (RRP) is the most common benign laryngeal tumour in children. It is caused by the human papillomavirus (HPV), in particular low-risk HPV6 and HPV11; aggressiveness varies among patients. RRP has two forms – juvenile onset RRP (JO-RRP) and adult onset RRP (AO-RRP). In this article we will be discussing the JO-RRP.
JO-RRP occurs via vertical transmission during pregnancy or is acquired at birth from an HPV-infected mother; it has a more aggressive clinical course than AO-RRP; however horizontal transmission can occur in JO-RRP thus sexual abuse should always be considered in pre-adolescent cases.
Derkay et al. estimated an incidence rate of 4.3 per 100,000 in JO-RRP. Key risk factors for JO-RRP include (being the first-born child, having a teenage mother who has genital condylomata and vaginal delivery).
Surprisingly, caesarean section was not found to be protective against JO-RRP, however it’s indicated on active genital HPV infection.
Children with JO-RRP are often diagnosed around three years of age; correct diagnosis might be delayed for years. Initially, children are treated for asthma, recurrent croup and reflux. JO-RRP can cause airway obstruction, hoarseness, difficulty feeding, and a child initially might present a life-threatening stridor requiring urgent surgical tracheotomy.
Diagnosis is made with clinic based flexible laryngoscopy, and bronchoscopy to further evaluate the tracheobronchial tree.
The natural history of JO-RRP is very unpredictable and differs from patient to patient, but anecdotal evidence suggests that HPV 11 has more aggressive presentation than HPV 6 in JO-RRP.
Patients often require multiple surgeries in a short amount of time and occasionally adjuvant therapy when surgery is unable to control the disease. The goal of managing these kinds of patients is to achieve adequate airway, improve voice quality and facilitate disease remission.
Traditional management of JO-RRP has been surgical excision in the operating room under general anaesthesia, primarily with potassium-titanyl-phosphate (KTP) lasers or microdebriders, with some surgeons also using CO2 lasers or cold steel instruments.
RRP remains a difficult disease to manage; for the most severe cases of RRP, medical adjuvant therapy is available. It should only be considered if indicated in persistent airway obstruction or can cause great psychological distress despite complete surgical excision.
Cidofovir, is an anti-viral medication, typically injected intralesional in a four to eight-week interval for eight to 10 doses per course. Once the course is completed, often the disease is less extensive or might even go into remission. Cidofovir’s main impact is to increase the interval period in between the surgical interventions rather than cure the disease. Finally, cidofovir is known to cause kidney and liver toxicity if systematically used. And intralesional might lead to malignant transformation.
Bevacizumab is an antineoplastic monoclonal antibody that blocks angiogenesis by inhibiting vascular endothelial growth factor A (VEGF-A). It showed synergistic effects when combined with angiolytic lasers (KTP/PDL). It has high reduction rate in recurrence.
While Gardisil is a Quadrivalent HPV vaccine against HPV subtypes (6,11,16,18). Most effective if administered to individuals who have not yet become sexually active. It is recommended to administer it to all boys and girls between 11-12 years of age. It also holds promise to eliminate maternal and paternal reservoir of HPV and lead to a near eradication of RRP caused by HPVs 6 and 11. Long-term results of widespread vaccination have not been established yet.
Interferon therapy is one of the first systemic adjuvant treatments used to manage RRP. The clinical efficacy of IFN therapy in the treatment of RRP is controversial and despite positive evidence for adjuvant IFN therapy, it is rarely used due to the emergence of intralesional adjuvants, such as cidofovir and bevacizumab, which have fewer local and systemic side effects.
Lastly, RRP is a benign laryngeal neoplasm that has no cure and the mainstay of treatment is to debulk the larynx to achieve a patent airway; the nature of this disease is to recur regardless of the extent of surgery. Therefore, its preferable to leave the disease in the larynx rather than damaging the larynx to achieve a complete resection. Adjuvant medical therapy is meant to decrease the frequency of surgery.
The importance of raising knowledge among healthcare practitioners is not to be underestimated. HPV is classified as a sexually transmitted disease but RRP is not. Therefore, such patients should be dealt with in a non-threatening environment and assured that their privacy will not to be violated.
To develop documentation forms to uniformly and objectively collect data from such patients will open up the floor for further advancement in communicating with sexually abused patients and to start calculating data among our society to develop preventive plans and to educate school going children about such diseases. It is also important to understand the mode of transmission and to council teenagers regarding the importance of vaccination in decreasing the chance of JO-RRP. Clinician’s should also raise their index of suspicion and report any JO-RRP case; children who have been abuse can’t be excluded.