Topical combination of diclofenac, calcipotriol, and difluoromethylornithine has beneficial effects comparable to 5-fluorouracil for the treatment of non-melanoma skin cancer in mice.

Non-melanoma skin cancer (NMSC) is the most common form of skin cancer. Owing to the significant adverse effects of existing treatments, alternatives are needed. The aim of this study was to evaluate the use of topically administered combination therapy and 5-flurouracil (5-FU) for the treatment of UVB induced NMSC in a mouse model. Ninety-six SKH-1 mice were randomized to one placebo group and two treatment groups (diclofenac+calcitriol+difluoromethylornithine (DFMO) and 5-FU). After UVB radiation for 20 weeks, the mice with tumours were treated topically for the following 17 weeks. Both treatments significantly reduced the number of tumours, number of mice with tumours as well as tumour area size compared with placebo. As the clinical use of 5-FU may induce more adverse effects, a combination of diclofenac+calcitriol+DFMO could be a promising alternative. Human studies are warranted to determine the beneficial effects and possible adverse effects of this new treatment.