Associations between ultraviolet radiation, basal cell carcinoma site and histology, host characteristics, and rate of development of further tumors

Background: Patients with basal cell carcinoma (BCC) frequently develop further tumors during follow up. Objective. We sought to elucidate the relative effects of pattern of ultraviolet radiation exposure, and site and histologic type of the first tumor, on the rate of increase in BCC numbers. Methods: We used negative binomial regression analysis to study the association of selected variables on the rate of increase in BCC numbers in 266 Caucasian patients who first presented with a tumor on the head/neck or trunk with nodular or superficial histology. Results: Patients with an initial truncal BCC with superficial histology demonstrated significantly faster increases in BCC numbers than did patients with other site and histology combinations. Conclusions: These data indicate that site and histology define subsets of patients with BCC.