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Prevention of nonmelanoma skin cancers remains a health priority due to high costs associated with this disease. Diclofenac and difluoromethylornithine (DFMO) have demonstrated chemopreventive efficacy for cutaneous squamous cell carcinomas. We designed a randomized study of the combination of DFMO and diclofenac in the treatment of sun-damaged skin. Individuals with visible cutaneous sun damage were eligible. Subjects were randomized to one of the three groups: topical DFMO applied twice daily, topical diclofenac applied daily, or DFMO plus diclofenac. The treatment was limited to an area on the left forearm, and the duration of use was 90 days. We hypothesized that combination therapy would have increased efficacy compared with single-agent therapy. The primary outcome was change in karyometric average nuclear abnormality (ANA) in the treated skin. Individuals assessing the biomarkers were blinded regarding the treatment for each subject. A total of 156 subjects were randomized; 144 had baseline and end-of-study biopsies, and 136 subjects completed the study. The ANA unexpectedly increased for all groups, with higher values correlating with clinical cutaneous inflammation. Nearly all of the adverse events were local cutaneous effects. One subject had cutaneous toxicity that required treatment discontinuation. Significantly more adverse events were seen in the groups taking diclofenac. Overall, the study indicated that the addition of topical DFMO to topical diclofenac did not enhance its activity. Both agents caused inflammation on a cellular and clinical level, which may have confounded the measurement of chemopreventive effects. More significant effects may be observed in subjects with greater baseline cutaneous damage., (©2015 American Association for Cancer Research.)

Objective: To determine whether low-dose topical applications of difluoromethylornithine (DFMO) with or without Triamcinolone (Fougena, Melville, New York, U.S.A.) to moderately sun-damaged skin with actinic skin keratoses are efficacious., Study Design: There were 4 topically administered, 6-month treatments, DFMO + Eucerin (Beiersdorf Inc., Hamburg, Germany), DFMO + Triamcinolone, Triamcinolone + Eucerin and Eucerin + Eucerin (to serve as double placebo). Participant eligibility included evidence of at least 2 actinic keratoses on each posterolateral forearm as well as moderate to severe evidence of sun-damaged skin, as evaluated by a board certified dermatologist. High resolution digitized imagery of nuclei from histologic sections of 4-mm punch biopsies from sun-damaged skin on the posterolateral forearms was recorded, at baseline and at the end of 6 months of study., Results: With 102 participants and 185 skin biopsies, a total of 16,395 skin cell nuclei were recorded. The nuclei were analyzed to assess the changes in the pattern of the nuclear chromatin. Two specific measures of end point evaluation were computed, including the percentage of nuclei with high values of nuclear abnormality and the reduction of the percentage of nuclei assigned by a discriminant function to the baseline data set. All 3 active interventions, including low-dose topical DFMO, topical Triamcinolone and topical DFMO + Triamcinolone, led to statistically significant reductions of both the number of nuclei with high nuclear abnormality as well as the number of nuclei assigned to the baseline data set. These reductions were found for all 3 treatments involving DFMO or Triamcinolone. For the placebo data sets only small, statistically insignificant increases or decreases of these percentages were observed., Conclusion: The low-dose, topical drug interventions were all effective in reducing skin biopsy nuclear abnormality by a statistically significant 15-20%, whereas there was no evidence of a double placebo effect by karyometric assessment. These effects were greater than the case-to-case sampling error.