Treatment of Bowen's disease with imiquimod 5% cream in transplant recipients.

Abstract

There is a dramatically increased incidence of epithelial skin neoplasms in transplant recipients (TR) (1). Bowen’s disease (BD), an intraepithelial form of squamous cell carcinoma, is one of the most common skin neoplasms in TR, often occurring multifocally and carrying the risk for progression into invasive and potentially fatal squamous cell carcinoma. Treatment for BD includes surgery, cryosurgery, topical 5-fluorouracil, and photodynamic therapy (2). Because these therapies are associated with pain, risk of postinterventional infections, and sometimes mutilating scaring, new therapeutic modalities for BD in TR are needed. The topical application of the immunomodulator imiquimod 5% cream (3) is highly effective in the treatment of BD, with a response rate of 93% in immunocompetent patients (4). In TR, imiquimod has only been applied in combination with 5-fluorouracil cream for the treatment of BD (5), but so far has never been used as a single-agent therapy. We report four male patients (age range, 37–58 years) with a total of four lesions, 1 to 4 cm in diameter, of histologically proven BD who were treated with imiquimod 5% cream as single-agent treatment. The tumors occurred after 17 years on average (range, 13–21 years) under long-term immunosuppressive medication after solid organ transplantation (two patients after renal transplantation and two after heart transplantation). Two of the four lesions of BD were located on the head, one lesion on the left ear and one on the left temple. Surgical treatment would have included a flap to close the tissue defect after excision. The two other BD lesions were on the back and on the finger. The lesions were treated every second day (three times per week) with imiquimod 5% cream under nonocclusive conditions. In case of no clinical response (i.e., erythema, erosion, or crusting) after 2 weeks, treatment was continued with daily application of imiquimod. The cream was applied on the lesions in the evening and washed off after 8 to 10 hr. No other systemic or topical treatment for BD was used. After 4 weeks of treatment, three of four lesions showed erythema, erosion, and crusting. One lesion on the back showed an immense inflammatory reaction, hemorrhagia, and crusting 8 days after treatment, and thus the treatment was stopped (Fig. 1). After an average of 6 weeks (range, 1–10 weeks), three of the four lesions (75%) showed complete clinical remission. No clinical response or inflammatory reaction was observed in the treated area of BD on the finger in one patient; thus, the treatment was discontinued after 8 weeks. All three lesions healed without scar formation. No systemic side effects were observed. There was no recurrence after 6 months. However, the lesion on the left temple recurred after 10 months.Figure 1: Bowen’s disease on the back with treatment with imiquimod 5% cream. (A) Before treatment. (B) After four times topical application every second day of imiquimod 5% cream. (C) Seven and a half months after cessation of treatment (with scar from the biopsy).Our results demonstrate a high efficacy and a good tolerability of topical treatment of imiquimod 5% cream in BD in TR, which represents a promising new therapeutic modality for BD, especially on exposed areas such as the face and ears. Our results may encourage larger and controlled studies to assess the safety profile and long-term efficacy of imiquimod in TR, particularly with multifocal BD. Bettina M. Prinz Juerg Hafner Reinhard Dummer Guenter Burg U. Bruswanger Werner Kempf