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.