Photodynamic therapy for the treatment of extramammary Paget's disease

Background: Surgical and ablative treatment modalities for extramammary Paget's disease (EMPD) have high recurrence rates and can be associated with significant morbidity. Objectives: To evaluate photodynamic therapy (PDT) for the treatment of EMPD. Methods: We conducted a retrospective review of notes and histology of five men with anogenital, groin and axillary EMPD treated with PDT at Roswell Park Cancer Institute between 20 April 1995 and 1 February 2001. Results: Sixteen EMPD lesions were treated with topical aminolaevulinic acid (ALA)-PDT. Eleven of these lesions had failed previous Mohs micrographic surgery, excision or laser ablation. When evaluated 6 months after one treatment with ALA-PDT, eight of 16 (50%) sites achieved a complete clinical response (CR); six of eight CRs were in lesions that had failed prior conventional therapies. Three of the eight CRs (37.5%) recurred at 9, 10 and 10 months. One patient who was partially responsive to topical ALA-PDT subsequently received systemic Photofrin®-PDT, with a complete clinical and histological response at 1 year. Functional and cosmetic outcome was excellent in all patients. Conclusions: PDT is an effective treatment for EMPD. Recurrence rates are high with topical ALA-PDT, but comparable with standard therapies. Topical ALA-PDT causes little scarring and is preferred for superficial disease and mucosal surfaces. Systemic Photofrin®-PDT may be better suited for bulky disease. While further studies are indicated, PDT is well tolerated and appears to be a useful therapy for EMPD.