Risk factors for histological types and anatomic sites of cutaneous basal-cell carcinoma: an italian case-control study.

Different clinico-pathologic subtypes and anatomic sites of basal-cell carcinoma (BCC) may display distinct characteristics and mechanisms of development. However, scanty information exists on potential differences in etiological factors for BCC according to histotype and anatomic location. Thus, we analyzed data from an Italian case-control study, including 528 subjects with newly diagnosed, histologically confirmed BCC and 512 controls admitted to the same hospitals with acute conditions. The multivariate odds ratio (OR) of nodular (OR=1.53) but not superficial (OR=0.71) BCC was increased for occupational exposure to sunlight. Considering the anatomic site of BCC, the corresponding values were 1.46 for head/neck and 0.74 for truncal location. Direct associations were observed with recreational sunlight exposure, eye color, red hair, and number and early age of severe sunburn episodes, along with some differences in risk between histotypes and anatomic sites. This study confirmed the role of (intermittent) sun exposure and phenotypic characteristics as risk factors for BCC, and suggested etiological differences between nodular and superficial histotypes and between head/neck and truncal locations.