Skin Phenotype and the Impact of Surveillance on Melanoma in New Zealand.

Few studies have been performed to evaluate the effect of skin surveillance on melanoma risk. This population-based case-control study was carried out to confirm the association of phenotype with melanoma and to investigate the effect of surveillance by skin examination on the risk of melanoma in New Zealand. Cases were patients with a first diagnosis of in-situ or invasive cutaneous malignant melanoma from three regions of New Zealand. Controls were selected at random from the electoral rolls and frequency-matched by age. Participants included men and women of European origin aged between 20 and 79 years. A strong association was found between host phenotypic factors (red hair, fair skin, many freckles on the face, and numbers of moles) and melanoma risk. These effects were largely independent of each other. The relative risk of melanoma was significantly reduced after skin examination by one's self, partner or a health professional; this reduction in risk remained after adjustment for phenotype, mole counts, skin reaction to sun, and exposure to sun. People who attended a 'skin check clinic' had a non-significant increase in risk of melanoma.