Imiquimod and lymphatic field clearance: a new hypothesis based on a remote immune action on skin cancer.

Basal cell carcinoma and actinic keratosis are frequent neoplasms. Topical treatments include the recently approved imiquimod cream. We describe here the case of a 68-year-old man with multiple actinic keratosis on the forehead, upper trunk and on the left cheek. In addition, an exulcerated basal cell carcinoma was observed. The patient was advised only to treat lesions on the forehead with imiquimod cream. This resulted in complete clearance of actinic keratosis within 6 weeks. At follow-up, a planned surgical excision of the basal cell carcinoma and actinic keratosis on the cheek was carried out. Histopathologically, both excision specimens no longer showed features of basal cell carcinoma or actinic keratosis, despite the fact that the imiquimod treatment was not applied to the cheek. Imiquimod cream is a topical immune response modifier, which has shown antiviral and anti-tumorous properties by inducing the production of cytokines as well as by stimulating dendritic cells and lymphocytes. Our observation supports the concept of lymphatic transport of immune cells and factors with subsequent immunological curing of tumours, not only in the treated area, but also those in the area between the imiquimod application site and the regional lymph nodes (the "lymphatic field clearance").

Efficacy and safety of imiquimod versus podophyllotoxin in the treatment of anogenital warts.

BACKGROUND: Anogenital warts are a common sexually transmitted disease caused by human papillomaviruses. Despite the fact, that imiquimod and podophyllotoxin represent common topical agents, direct comparative studies lack. This work compares the effectiveness and safety of self-applied imiquimod 5% cream and podophyllotoxin 0.5% solution. METHODS: Within 2 years, consecutive patients presenting with untreated anogenital warts were included in a randomized, open label trial. The primary endpoint was complete clearance at the end of treatment (4 weeks after the start with podophyllotoxin, 16 weeks after the start of imiquimod therapy). Side effects were evaluated as a secondary endpoint. RESULTS: A total of 45 patients, 7 women and 35 men, of whom 5 were circumcised, concluded the treatment and were eligible for evaluation. The rates of clearance of baseline warts among treatment groups were 72% (95% confidence interval [CI], 52%-86%) in the podophyllotoxin group and 75% (95% CI, 53%-98%) in the imiquimod group. Statistically, clearance rates were identical (P=1). The differences in side effects between treatment groups were statistically not significant (P=0.24). CONCLUSIONS: The current study, a direct comparison of both, confirms the previously obtained mathematical data, that imiquimod 5% cream and podophyllotoxin 0.5% solution have an identical beneficial effect on anogenital warts and are associated with identical and acceptable side effects. Both substances constitute effective and safe treatments of untreated anogenital warts in immunocompetent individuals.