Background: The most widely used topical agents for the field-based treatment of multiple actinic keratoses (AKs) are 5-fluorouracil and imiquimod, but their comparative effectiveness has not been assessed in a real-world setting.
Objective: We compared the effectiveness of 5-fluorouracil and imiquimod in reducing risk for subsequent AKs in a large, integrated health care delivery system in northern California.
Methods: In this cohort study, we identified adult health plan members who had an AK diagnosed in 2007 and who subsequently filled a prescription for 5-fluorouracil or imiquimod (N = 5700). We followed subjects for subsequent AKs identified by the International Classification of Diseases codes and estimated the 2-year (short-term) and 5-year (long-term) differences in cumulative risk while controlling for potential confounding by pretreatment variables.
Results: 5-Fluorouracil reduced the short-term incidence of subsequent AKs (cumulative risk difference -4.54% [95% confidence interval, -7.91% to -1.17%]), but there was no statistically significant evidence of a long-term decreased risk (cumulative risk difference -1.43% [95% confidence interval, -3.43% to 0.05%]) compared with that with imiquimod.
Limitations: This is a retrospective study with limited ascertainment of all relevant potential confounding variables.
Conclusion: We found that 5-fluorouracil appeared to be significantly more effective than imiquimod in the short-term, but not long-term, prevention of subsequent AKs.
Keywords: actinic keratosis; basal cell carcinoma; comparative effectiveness; keratinocyte carcinoma; skin cancer; squamous cell carcinoma.
Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.