A comparison of risk factors for malignant melanoma, squamous cell carcinoma and basal cell carcinoma in the UK.

Cutaneous malignant melanoma (MM), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) exhibit markedly different natural histories, but few studies have compared risk factors in individuals from a single population. Using logistic regression analysis in case and control groups, we assessed, the association of individual characteristics with MM (n = 240) and SCC (n = 184). We also compared differences in risk factors (eye/hair colour, skin type, smoking history, occupation, social class, tumour site) between MM/BCC and SCC/BCC. MM patients were more likely to have red/blonde hair and blue/green eyes than controls, and those with SCC more likely to have red/blonde hair, blue/green eyes, outdoor occupation, skin type 1 and to have smoked more. There were few differences in individual characteristics between the skin cancer groups, illustrating their non-specific nature. Tumour site, however, showed marked differences: MM patients were more likely to have a tumour on the trunk or limbs than BCC patients, while patients with SCC were more likely to have a tumour on the limbs. Reasons for this variation are unclear. The relatively weak effect of individual factors supports the view of a multifactorial disease and suggests that interactions between UV exposure and genetic predisposition may be more significant determinants of risk.