Treatment of extramammary Paget's disease with imiquimod in a real-life setting: a multicenter retrospective analysis in Spain.

ABSTRACT

BACKGROUND: Topical imiquimod has shown to be an effective treatment for EMPD, although available evidence supporting its use is based on case reports and small series of patients. OBJECTIVES: To investigate the therapeutic outcomes and analyze potential clinico-pathological factors associated with imiquimod response in a large cohort of EMPD patients. METHODS: Retrospective chart review of 125 EMPD patients treated with imiquimod at 20 Spanish tertiary-care hospitals. RESULTS: During the study period, patients received 134 treatment regimens with imiquimod, with 70 (52.2%) cases achieving complete response (CR), 41 (30.6%) partial response and 23 (17.2%) no response. The cumulative CR rates at 24 and 48 weeks of treatment were 46.3% and 71.8%, respectively, without significant differences between first-time and previously treated EMPD. Larger lesions (≥6 cm; p = 0.038) and EMPD affecting >1 anatomical site (p = 0.002) were significantly associated with a worse treatment response. However, the CR rate did not differ significantly by the number of treatment applications (≤4 vs. > 4 times/week; p = 0.112). Among patients who achieved CR, 30 (42.9%) developed local recurrences during a mean follow-up period of 36 months, with an estimated 3 and 5-year recurrence free-survival of 55.7% and 36.4%, respectively. CONCLUSIONS: Imiquimod appears as an effective therapeutic alternative for both first-line and previously treated EMPD lesions. However, a less favorable therapeutic response could be expected in larger lesions and those affecting >1 anatomical site. Based on our results, a 3-4 times weekly regimen of imiquimod with a treatment duration of at least 6 months could be considered an appropriate therapeutic strategy for EMPD patients.