Risk factors for basal cell carcinoma in a southern Brazilian population: a case-control study

Background Basal cell carcinoma (BCC) is the most common cancer to occur in Caucasian populations, and its incidence is increasing. Despite its frequency, there is a paucity of data on risk factors for BCC in some regions. Objectives This study investigated the association between pigmentary characteristics, distinctive patterns of solar exposure, habits and lifestyle, and risk for BCC among patients attending a dermatology center in a region in southern Brazil. Methods We conducted a hospital-based, case-control study that included 127 case patients with histologically confirmed BCC and 280 cancer-free control subjects with other dermatologic conditions, observed between January 2006 and December 2007. The study was conducted using a questionnaire and physical examination by a dermatologist. Relative risks were estimated using exposure odds ratios generated by cross-tabulation and logistic regression models. Results Risk for BCC was associated with family history of skin cancer, Fitzpatrick skin type I, and the presence of actinic keratoses, solar lentigines, leukoderma, and elastosis romboidalis nuchae. No effect was found for different patterns of solar exposure, eye, hair or skin color, exposure to non-solar ultraviolet radiation (UVR), or lifestyle-related habits such as sunscreen use and cigarette smoking. Conclusions The results of this study suggest that skin type and family history of skin cancer may be important in establishing risk for developing BCC. Additionally, the detection by clinical examination of skin markers related to UVR action is important in establishing which patients are more likely to develop BCC.