The most important of the lesions included under the heading of skin cancer are epidermoid carcinoma (either squamous cell or basal cell) and melanoma. They are of particular significance to the practitioner because they are:

1. Common. This is particularly true in regard to the epidermoid variety which, in some parts of this country, is the most commonly encountered human cancer.

2. Accessible. Most of these lesions occur on exposed skin surfaces where they are readily detectable from their earliest beginnings.

3. Often misdiagnosed or mistreated. Frequently, because they are so readily observable and apparently innocuous in appearance, treatment is delayed -or is indequate or inappropriate.

4. Readily curable. Those lesions which make up the great bulk of skin cancers have curability rates of over 90%. For the relatively uncommon melanoma, of course, the outlook is considerably less promising but is far better than is generally realized if certain principles are observed.

5. Often preceded by premalignant lesions. In the case of the epidermoid lesion, these may take the form of certain keratoses of the so-called senile or other types. For melanomas, the junctional nevus is widely held to be the premalignant lesion.

6. Often preventable. Detection of and removal of premalignant lesions such as those mentioned previously will prevent their subsequent transformation into cancer. Also, etiologic or predisposing factors are known for a number of skin cancers. Avoidance or modification of exposure by individuals or groups to such diverse factors as excessive sunlight, radiation, and certain occupational hazards will prevent a significant amount of skin cancer.

Epidemiology. Incidence

Mortality

Rates And Ratios

Trend Last Ten Years (All Skin Cancer)

Age (All Skin Cancer)

Geographic Distribution

There is an increased risk of epidermoid carcinoma in all geographic regions with prolonged exposure to sunshine. The highest reported rates are in Australia and in the white population of South Africa.