Imiquimod for the treatment of Bowen's disease and invasive squamous cell carcinoma

Journal of Drugs in Dermatology, Dec, 2003 by Keyvan Nouri, Christopher O'Connell, Maria Patricia Rivas

Abstract

Topical imiquimod is an immune response modifier FDA approved for the treatment of anogenital warts. Recent studies have reported its effectiveness in the treatment of some types of basal cell carcinomas. There have also been some case reports and case series reporting success treating of squamous cell carcinoma in situ with imiquimod. We report two patients with squamous cell carcinoma in situ and one with invasive squamous cell carcinoma treated with 5% imiquimod cream. Lesions were located on shin, posterior shoulder, and nasal tip. 5% imiquimod cream was applied at night for six weeks. Side effects included erythema and crusting in one patient. Biopsies taken four weeks after treatment revealed no residual squamous cell carcinoma in situ or squamous cell carcinoma. Topical 5% imiquimod cream is becoming established as a promising treatment for squamous cell carcinoma in situ. It also seems to be an alternative treatment for some cases of squamous cell carcinoma.

Introduction

There are several options for the treatment of squamous cell carcinoma, including: surgical excision, 5-fluorouracil, electro-dessication and curettage, laser vaporization, chemical peel, cryotherapy, and Mohs micrographic surgery. Some of these proposed treatments are limited by significant morbidity and high recurrence rates. Consequently, the search for treatment innovations continues.

Topical imiquimod is an immune response modifier currently FDA approved for the treatment of anogenital warts. Its antiviral and anti-tumor activities have been linked to the stimulation of local cytokine production and cell-mediated immune response.

Recent studies have reported that topical imiquimod is effective in the treatment of basal cell carcinomas (1-6). There have also been some case reports and case series on its use in the treatment of squamous cell carcinoma in situ (7-10). We report two patients with squamous cell carcinoma in situ and one with invasive squamous cell carcinoma who received treatment with topical imiquimod.

Patients and Methods

The three patients ranged in age from 73 to 79 (Table 1). There were two women and one man. Diagnoses were squamous cell carcinoma in situ (n=2) and squamous cell carcinoma (n=1). Lesion sizes ranged from 0.3 to 1 cm. Locations were lower leg (n=l), posterior shoulder (n=1), and nasal tip (n=1). Treatment options were explained to patients. The three patients refused surgical intervention, but were interested in a trial of imiquimod. Patients were advised of possible side effects such as erythema, swelling, induration, crusting, ulceration, pain, and burning. Patients were instructed to apply 5% imiquimod cream every, night over the entire lesion for six weeks. Patients were seen in clinic for follow up midway through treatment. One month after completion of the imiquimod regimen, lesions were reevaluated and biopsies taken. At each of these visits, patients were evaluated for any side effects and these were carefully noted (Figures 1A-B and 2A-D).

[FIGURE 1-2 OMITTED]

Case Report--Patient 3

A 79 year old white female was seen in clinic for evaluation of three lesions: a scaly patch on the nasal bridge, an erythematous plaque on the tip of her nose, and a pearly papule in the right nasal sulcus (Figure 2A). All lesions were biopsied. Diagnosis by pathology was actinic keratosis on the nasal bridge, invasive squamous cell carcinoma of the superficial type on right nasal tip, and basal cell carcinoma of right nasal sulcus.

Patient vehemently refused surgical intervention and other tissue destructive measures such as cryotherapy. Options were discussed with the patient and she expressed interest in a topical agent. Studies with imiquimod have shown success with the treatment of basal cell carcinoma, and host of case reports and cases series have shown imiquimod as effective in the treatment of squamous cell carcinoma in situ. Therefore, imiquimod was discussed as an option for the treatment of both lesions. Side effects of imiquimod were discussed with the patient. She was made to understand that this treatment, though valid, was not a first line treatment. Understanding these parameters, she contracted to maintain close follow-up with us. Treatment of both the basal cell carcinoma and squamous cell carcinoma was then undertaken: 5% imiquimod was to be applied to both lesions at night for six weeks.

This patient developed irritation and crusting of the treatment area midway through treatment (Figure 2B). At this time the patient was allowed to stop applying imiquimod for two weeks. She was told to restart treatment for another three weeks to complete a total of six weeks of treatment.

One month post treatment, this patient had no visible erythema and no clinically visible lesions on the nasal bridge, nasal tip, or nasal sulcus (Figures 2C and 2D). At this time, shave biopsies of the nasal tip and nasal sulcus were taken. Both biopsies showed dermal cicatrix, but no residual squamous cell carcinoma, or basal cell carcinoma.