Topical 5-aminolaevulinic acid-photodynamic therapy for the treatment of urethral condylomata acuminata

BACKGROUND: Electrocoagulation and laser evaporation for urethral condylomata acuminata have high recurrence rates and can be associated with urethral malformations. OBJECTIVES: To investigate the effect of photodynamic therapy (PDT) with topical 5-aminolaevulinic acid (ALA) on urethral condylomata acuminata and to examine the histological changes in lesions of condylomata acuminata after ALA-PDT. METHODS: Patients with urethral condylomata (n = 164) were given topical ALA followed by intraurethral PDT through a cylindrical fibre. Patients included 11 individuals with 16 penile or vulval condylomatous lesions which were biopsied before or after treatment; the histological changes were then evaluated by light microscopy and electron microscopy. RESULTS: The complete response rate was 95% and the recurrence rate was 5% after 6-24 months of follow-up. Light microscopy revealed keratinocytes in the middle and upper layers of the epidermis showing marked vacuolation and some necrocytosis 1 and 3 h after PDT. Necrosis in all layers of the epidermis was noted 5 h after PDT. Electron microscopy of keratinocytes revealed distinct ultrastructural abnormalities of mitochondria and the endoplasmic reticulum, and membrane damage. Apoptotic bodies were detected 3 h after PDT and a large number of keratinocytes exhibited necrosis 5 h after PDT. CONCLUSIONS: Results suggest that, compared with conventional therapies, topical ALA-PDT is a simple, effective, safe and well-tolerated treatment for urethral condylomata acuminata that is associated with a low recurrence rate. The mechanism might be the triggering of both apoptosis and necrosis by ALA-PDT in human papillomavirus-infected keratinocytes.