May 1st 2007ABSTRACT: Prevention of skin cancer requires photoprotection (eg, the use of a sunscreen with both UVB and UVA protection) and regular monitoring of the skin for suspicious lesions. Encourage patients to examine all areas of their skin, including the interdigital and genital regions, for unusual macules, papules, and nodules. Teach patients the "ABCDE" warning signs of melanoma (asymmetry, border irregularity, color variegation, diameter greater than 0.5 cm, evolving lesion). Office skin examinations are recommended for patients with risk factors for skin cancer and for those with obvious sun damage. Correct lighting, preferably daylight, and cross-illumination are crucial. Palpation may be helpful in detecting lesions such as actinic keratoses, which have a gritty, sandpaper-like surface.