Background Actinic keratoses (AKs) represent in situ carcinomas. Therefore, effective treatment is mandatory.
Objectives We investigated the effect of topical 3.0% diclofenac in 2.5% hyaluronic acid gel on AKs on the base of 90 days of treatment (group A) and 180 days of treatment (group B).
Methods 65 patients (group A) and 41 patients (group B) were clinically evaluated before and after 3 months’ treatment with topical 3.0% diclofenac in 2.5% hyaluronic acid gel. Biopsy specimen were taken and stained with haematoxylin-eosin and immunohistological markers (anti-p53 antibody, anti-MIB-1 antibody). Specimens were evaluated for histological type of AKs using the classification scheme suggested by Rowert-Huber et al. [(early) in situ squamous cell carcinoma type AK Grade I–III)], number of mitoses per high-power field and expression of immunohistological markers.
Results Complete clinical resolution was observed in 16.9% (group A) and 19.5% (group B). In both treatment groups a significant (P<0.001) downgrading concerning the AK I–III classification scheme was found. Histological resolution was achieved in 23.1% (group A) and 19.5% (group B). The number of mitoses per high-power field was reduced significantly (P<0.001) in both groups. The expression of anti-p53 antibody decreased significantly in group A (P<0.009) as did group B (P<0.001). A significant depletion for anti-MIB-1 antibody was seen in group A (P< 0.021) and group B (P<0.001). Comparing both treatment periods no significant differenced were found concerning clinical and histological resolution, histological downgrading of AKs, and number of mitoses per high power field. Exhibition of anti-p53 antibody was reduced more pronounced after 180 days of treatment (P=0.025) as did anti-MIB-1 antibody (P<0.040).
Conclusion 3.0% diclofenac in 2.5% hyaluronic acid gel causes regression of cancerous transformation in actinic keratoses. The effect of treatment after 90 days can be maintained by prolongation of treatment to 180 days. Further improvement on the clinical and histological level could not be achieved, however, it could be demonstrated that prolongation of treatment leads to refinement of immunohistological parameters of cancerous transformation and proliferation.