Treatment of Cutaneous Squamous Cell Carcinoma In Situ With Curettage Followed by Topical Imiquimod 5% Cream.

BACKGROUND: Treatment strategies for cutaneous squamous cell carcinoma in situ (cSCCIS) are many but reported cure rates are variable and few studies report 5-year follow-up data. OBJECTIVE: To evaluate the treatment of cSCCIS by curettage followed by topical imiquimod 5% cream (C&I). METHODS: We evaluated all immunocompetent patients with biopsy proven cSCCIS treated by C&I between January 2008 and December 2012. RESULTS: A total of 861 patients with 1,198 cSCCIS were treated, with median follow-up of 71 months. The mean tumor diameter was 10.2 mm. The average duration of treatment with imiquimod 5% cream was 21 days. Kaplan-Meier estimated recurrence-free survival at 5-year follow-up was 99.71% with 95% CI (99.38%, 100.00%). A follow-up questionnaire returned by 45% of patients revealed that 94% were satisfied with their treatment. Six hundred eleven patients developed a new nonmelanoma skin cancer (NMSC) during the follow-up period, and 91% (556/611) of patients chose this combination treatment for at least one new NMSC. CONCLUSION: The combination treatment for cSCCIS of C&I had less than 1% cumulative probability of treatment failure at 5 years. Patients tolerated the treatment well, with the majority choosing this method of treatment for at least one new NMSC.