Predictors for cutaneous basal- and squamous-cell carcinoma among actinically damaged adults

Risk factors for non-melanoma skin cancer among populations with evidence of precursor damage are not well described. We examined and compared risk factors associated with the development of cutaneous basal-cell (BCC) or squamous-cell (SCC) carcinoma among a group of 918 adults with significant sun damage (≥10 clinically assessable actinic keratoses) but no prior history of skin cancer. These adults were participants in a 5-year skin chemoprevention trial between 1985 and 1992, who had been randomized to the placebo group and followed for occurrence of skin cancer. During the study, a total of 129 first SCC and 164 first BCC lesions were diagnosed. The overall BCC and SCC incidence rates for this group of men and women, mean age 61 years, were 4,106 and 3,198 per 100,000 person-years, respectively. Different constitutional and exposure factors were independently associated with BCC compared to SCC. Only increased age independently predicted BCC occurrence among this population. In contrast, older age along with male gender, natural red hair color and adult residence in Arizona for 10 or more years independently predicted SCC occurrence. The substantial incidence of skin cancer found among this population confirms the need for active dermatological monitoring among individuals with multiple visible actinic lesions.