RELATIVE IMPORTANCE OF PRIOR BASAL-CELL CARCINOMAS, CONTINUING SUN EXPOSURE, AND CIRCULATING LYMPHOCYTES-T ON THE DEVELOPMENT OF BASAL-CELL CARCINOMA

This 36-month prospective study of a group of 61 people at high risk to develop multiple basal cell carcinomas (BCC) examined the circulating lymphocyte subsets of the population, patterns of sun exposure, and the longitudinal development of basal cell carcinoma. Sun exposure status was highly correlated with immune status defined by the CD4/CD8 T-lymphocyte ratio. There were significantly more BCC at 18 and 36 months in the 35 patients with high sun exposure and low CD4/CD8 ratio than in the 20 patients with low sun exposure and high CD4/CD8 ratio. A multivariate analysis assessed the relative importance of prior basal cell carcinoma, sun exposure, and immune status on the development of the skin cancer. Basal cell carcinoma developing in the previous 18 months and sun exposure during those 18 months were the first and second most important variables in determining development of basal cell carcinoma during the next 18 months. CD4/CD8 ratio had no additional predictive ability once prior skin cancers and sun exposure were accounted for. A low ratio of CD4/CD8 cels correlated with high sun exposure during the preceding 18 months.