PDT IN CHILDREN
PAEDIATRIC APPLICATIONS AND SPECIAL CONSIDERATIONS

Recurrent respiratory papillomatosis (RRP) is a chronic, potentially debilitating condition caused by HPV types 6 and 11 in the larynx and airways. In children, it typically presents in the first years of life with hoarseness, stridor, and progressively impaired breathing. The disease is not malignant but is relentlessly recurrent — requiring repeat surgical removal (microlaryngoscopy or bronchoscopy) every few weeks to months.

“Some children with severe RRP undergo 30, 50, or even 100+ surgical procedures over their childhood. Any treatment that extends the interval between procedures significantly improves quality of life for the child and the family. PDT is one of the few adjuvant therapies with meaningful evidence in this indication.”

• Why RRP Is so Difficult to Control

  HPV is integrated into the mucosal cells of the larynx and tracheobronchial tree. Surgical removal clears visible papillomas but leaves HPV-infected mucosa throughout the airway — explaining relentless recurrence. Antiviral therapies for HPV are ineffective systemically. Adjuvant approaches (cidofovir injections, bevacizumab injections, PDT) aim to reduce recurrence frequency without curing the underlying viral infection.

• How PDT Helps in RRP

  Photofrin PDT administered bronchoscopically after surgical debulking treats the HPV-infected mucosal field beyond visible papillomas — potentially suppressing subclinical viral activity in the treated area. Multiple published series show reduction in surgical frequency (from every 4–6 weeks to every 3–6 months in responders) and in some patients, prolonged disease-free intervals. PDT does not cure RRP but can meaningfully reduce the surgical burden.

Beyond RRP, PDT has established and emerging applications in several paediatric conditions — mostly outside oncology, in benign conditions where its tissue-sparing properties are particularly valued.

• Port-Wine Stains (Capillary Vascular Malformations)

  Vascular-targeted PDT using verteporfin (Visudyne) targets the abnormal blood vessels in port-wine stains — the discoloured vascular birthmarks present from birth. PDT selectively damages the ectatic capillaries without injuring the overlying epidermis, producing lightening of the stain. Multiple sessions are typically required. PDT is an established option, particularly for darker port-wine stains on the face that are resistant to pulsed dye laser.

• Lymphatic Malformations

  Lymphatic malformations — congenital dilated lymphatic channels in the head, neck, and axilla — cause cosmetic deformity, infection, and airway compromise in children. ALA-PDT and Photofrin PDT have been used to treat superficial components of lymphatic malformations, achieving reduction in volume and symptom relief in selected cases. Sclerotherapy remains the primary treatment, but PDT fills a role for superficial or recurrent cases.

• Paediatric Skin Cancer (Rare)

  While skin cancer is rare in children, xeroderma pigmentosum (XP) — a genetic DNA repair disorder causing extreme sun sensitivity and multiple skin cancers from early childhood — is a special indication for PDT. Children with XP develop numerous skin cancers and pre-cancers (actinic keratoses) requiring ongoing treatment. ALA-PDT for field cancerisation management in XP is used at specialist centres and avoids the cumulative surgical scarring that repeated excisions would cause.

• Selected Paediatric Cancers (Off-Label)

  Rare paediatric solid tumours in accessible locations — head and neck rhabdomyosarcoma, selected skin metastases, and superficial periorbital tumours — have been treated with PDT in individual case reports and small series at specialist centres. This is not a standard indication and requires experienced paediatric oncology and PDT team assessment.

Paediatric PDT requires specific adaptations in dosing, anaesthesia, consent, and photosensitivity management that differ substantially from adult practice.

• Dosing: Weight-Based, Same as Adults

  Photofrin dosing for children follows the same weight-based calculation as adults — 2 mg/kg IV. There is no paediatric dose adjustment required for the photosensitiser itself. For ALA skin PDT, the standard adult concentrations and application times are used for children. The key dosing consideration is accurate weight measurement and careful drug reconstitution for smaller doses in younger children.

• Anaesthesia: General Anaesthesia Required

  Children require general anaesthesia for bronchoscopic or endoscopic PDT procedures — conscious sedation is not appropriate for airway procedures in paediatric patients. This increases procedural risk compared to adult conscious sedation, and requires paediatric anaesthesia support. Photofrin injection is given prior to the anaesthesia date; the 40–50 hour waiting period occurs between injection and the light delivery procedure under GA.

• Photosensitivity Management in Children: The Biggest Challenge

  Managing Photofrin's 4–6 week photosensitivity in children is significantly more demanding than in adults. Young children cannot be reliably instructed to avoid light exposure; they cannot understand the risk of sun exposure and may run outside before anyone can stop them. Practical management requires: complete indoor confinement for the first 2 weeks, blackout curtains, covering all skin whenever outdoors, and constant vigilance from caregivers. Full family preparation and support before PDT is mandatory.

• Consent: Parents, Assent, and Multidisciplinary Decision-Making

  Informed consent for paediatric PDT is provided by parents or legal guardians. For older children and adolescents (typically >12 years), assent — the child's agreement to participate in treatment — is sought in addition to parental consent. Paediatric PDT decisions involve the treating specialist (ENT, pulmonologist, dermatologist, or paediatric oncologist), the PDT team, and ideally a paediatric ethics or MDT review for unusual indications.

Overview of established and emerging PDT applications in paediatric patients.

Related PDT topics and resources.

Frequently Asked Questions

Common questions about PDT in children.