The use of a sunscreen containing DNA-photolyase in the treatment of patients with field cancerization and multiple actinic keratoses: a case-series.

Cutaneous field cancerization (CFC) is associated witha high-risk of developing cutaneous squamous cellcarcinoma (cSCC). It manifests as actinic keratoses(AK) as one of the few macroscopic alterations in CFCpatients. A prospective, single-arm, case-series wasperformed to evaluate the utility of a novel sunscreencontaining DNA-photolyase for treatment of CFCin nine subjects (mean age 70.6 years, male: femaleratio 5:4). The cream was applied topically twicedaily on CFC/AK areas and patients were followedup for three months, with no other treatments. Theprimary outcome was the overall response rate (ORR),categorized as complete response (CR, completeresolution of AKs), partial response (PR, reduction inthe number of AKs), and no-response (NR, similar/increase in number of AKs). A 100% PR was observed.All subjects displayed at minimum, a 50% reductionin their lesion number and most patients experiencedalmost CR. Evaluation of AK numbers revealed anabsolute count reduction of 76.6% in the number oflesions, with the mean number of lesions reducedfrom 13.4 to 3.1 (p < 0.0001). No adverse events werereported. Patients with CFC may benefit from noveltopical applications containing DNA-photolyase,at minimum, as complementary therapy for themanagement of CFC disease. We propose a newconcept called "active photoprotection" because of itsdual mechanism involving therapy and protection.