Background Actinic keratoses (AK) frequently occur on sun-exposed skin and are considered as in situ squamous cell carcinoma. To date, no treatment algorithm exists for first or second line therapies due to the lack of comparative studies.
Objective This study compared the initial and 12-month clinical clearance, histological clearance, and cosmetic outcomes of topically applied 5% imiquimod (IMIQ) cream, 5% 5-fluorouracil (5-FU) ointment and cryosurgery for the treatment of AK.
Patients/methods Patients were randomised to one of the following three treatment groups: one or two courses of cryosurgery (20–40 s per lesion), topical 5-FU (twice daily for 4 weeks), or one or two courses of topical imquimod (three times per week for 4 weeks each).
Results Sixty-eight per cent (17/25) of patients treated with cryosurgery, 96% (23/24) of patients treated with 5-FU, and 85% (22/26) of patients treated with IMIQ achieved initial clinical clearance, p = 0·03. The histological clearance rate for cryosurgery was 32% (8/25), 67% (16/24) for 5-FU, and 73% (19/26) in the IMIQ group, p = 0·03. The 12-month follow-up showed a high rate of recurrent and new lesions in the 5-FU and cryosurgery arms. The sustained clearance rate of initially cleared individual lesions was 28% (7/25) for cryosurgery, 54% (13/24) for 5-FU and 73% (19/26) for IMIQ (p < 0·01). Sustained clearance of the total treatment field was 4% (1/25), 33% (8/24), and 73% (19/26) of patients after cryosurgery, 5-FU, and IMIQ, respectively (p < 0·01). The patients in the IMIQ group were judged to have the best cosmetic outcomes (p = 0·0001).
Conclusion Imiquimod treatment of AK resulted in superior sustained clearance and cosmetic outcomes compared with cryosurgery and 5-FU. It should be considered as a first line therapy for sustained treatment of AK.