Photodynamic therapy with M-ALA as non surgical treatment option in patients with primary extramammary Paget's disease

Introduction: Extramammary Paget disease (EMPD) is a rare neoplasm of the skin that presents with erythematous or leukoplacic plaques causing pruritus and pain. Standard treatment is surgical but local failures and recurrences are frequent, leading to multiple mutilating surgeries. Aim of the study is to evaluate the effectiveness of photodynamic therapy (PDT) to obtain a clinical response and symptom control with a non surgical approach in these patients.

Materials and methods: After disease extension evaluation and symptoms assessment women with EMPD were prospectively treated with aminolevulinic-acid methyl-esther (M-ALA) PDT. Clinical and symptoms response were evaluated after 3 cycles and after any further PDT.

Results: Thirty-two patients with vulvar EMPD underwent M-ALA PDT. In sixteen (50%) patients the lesion extended to the perineal and/or perianal area. After three courses of treatment, three patients (9.4%) had a complete resolution of the symptoms; 25 patients (78.1%) a partial resolution and a stable disease was recorded in four patients (12.5%). None of the patients had progression of disease. Both size of the lesion and EMPD associated symptoms decreased significantly after three courses of treatment. Eighteen patients (56.2%) recurred and 16 (88.9%) were treated with further PDT. Among the 26 patients who underwent a further PDT, 16 patients (61.5%) achieved at least a partial response.

Conclusion: M-ALA PDT even if not curative is a reliable strategy to control EMPD and its associated symptoms even in an outpatient setting. M-ALA PDT is able to control large and multiple lesions regardless of the area involved, preserving cosmetic and/or functional anatomy.