Skin cancer is a malignant growth on the skin. It normally develops in the epidermis which is the outermost layer of the skin and is therefore visible. Basal cell cancer, squamous cell cancer and melanoma are the three most common types of skin cancer. Basal cell carcinomas are the most common and easy to treat by use of surgery or radiation. They rarely metastasize. Squamous cell carcinomas on the other hand are less common and metastasize more often than basal cell carcinoma. Although melanoma is less common, it is the most serious once it has spread.

Overexposure to UV radiation can cause skin cancer by directly or indirectly damaging the DNA. Sun exposure between 10am and 4pm is usually the most intense and is usually deemed the most harmful. Chronic non-healing wounds particularly burns can lead to squamous cell carcinoma. Human papilloma virus is also associated with squamous cell carcinoma. Normally skin cancer has a latency period of between 20 to 30 years.

Malignant melanoma is responsible for about three quarters of all skin cancer-related deaths and sunscreen may not be effective in protecting against this type. One major symptom that one has cancer of the skin is changing in the skin. Other signs of skin cancer are discolored skin and ulcering in the skin. Visual appearance or use of a dermatoscope are used in the clinical diagnosis of the disease and a skin biopsy is later used to confirm the results.

Treatment of skin cancer depends on the type and the location of the cancer. Other factors include the age of the patient and if the cancer is primary or recurrence. Radiation therapy, topical chemotherapy and cryotherapy are used in the treatment of skin cancer.