Photodynamic therapy for extramammary paget’s disease: A retrospective analysis of 15 cases

• This retrospective study evaluated photodynamic therapy (PDT) in 15 extramammary Paget’s disease (EMPD) patients, achieving 40 % complete and 46.7 % partial remission. • PDT was well-tolerated, with transient pain, mild erythema/edema, occasional local infection or scarring, and no functional impairment. • However, 4 of 6 complete responders relapsed 11–87 months later, underscoring suboptimal long-term control. • Lesion thickness, prior treatments, and photosensitizer choice (topical ALA vs systemic HpD) influenced outcomes; combination or repeat sessions improved response. • We conclude PDT is a safe, organ-sparing option for inoperable or recurrent EMPD, but larger prospective trials and combination strategies are needed to raise cure rates and reduce recurrence. Extramammary Paget's disease (EMPD) is a rare cutaneous malignancy. Photodynamic therapy (PDT) has shown promise as a treatment option for various skin cancers, including EMPD. This study aims to assess the clinical effectiveness of PDT in treating 15 cases of EMPD. A retrospective analysis was conducted on 15 patients diagnosed with EMPD in the Oncology Department of Southern Medical University Hospital of Integrated Traditional Chinese and Western Medicine from June 2014 to December 2024, all of whom received PDT as part of their treatment. According to the therapeutic regimens, patients were stratified into three cohorts: group A received systemic hematoporphyrin-derivative (HpD) PDT (with or without sequential ALA-PDT); group B underwent surgical excision followed by ALA-PDT as an adjunct; and group C was treated with ALA-PDT alone. Clinical outcomes, including lesion regression, recurrence rates, and adverse events, were evaluated during the follow-up period. The treatment of EMPD with PDT resulted in significant clinical improvement in most patients. Complete remission was achieved in 6 of 15 patients (40%), partial remission was observed in 7 patients (46.7%). In Group A, complete response was observed in 2 patients, partial response in 6 patients, and minimal response in 1 patient. All three patients in Group B achieved complete response. Group C had one patient in each category (CR 33 %, PR 33 %, MR 33 %). Treatment response was significantly more favourable in group B, in which all patients achieved a complete response (ordered logistic regression, P = 0.031; Group B vs Group A, OR = 18.0). However, among the six patients who achieved complete remission, four experienced disease recurrence during the subsequent follow-up period. The most common complaint was pain. Local infection and scarring were also observed in a small proportion of patients. PDT shows promising results as a non-invasive treatment option for EMPD, providing a favorable balance between effectiveness and safety. The short-term efficacy of photodynamic therapy is highly encouraging; however, its long-term efficacy remains suboptimal. For patients who are unwilling or unsuitable for surgery, photodynamic therapy is a viable alternative. Although photodynamic therapy can achieve complete remission of lesions in some patients, its cure rate is relatively low, and there is a risk of recurrence. Further studies with larger sample sizes are needed to confirm these findings and investigate long-term outcomes.