Nonmelanoma skin cancer (NMSC) is a type of cancer that develops in the skin's outermost layer, typically on areas of the skin that have been exposed to the sun. It is the most common type of cancer in the United States, with over 3 million cases diagnosed annually.

There are two main types of nonmelanoma skin cancer:

• Basal cell carcinoma (BCC): A slow-growing cancer that typically appears as a small, shiny bump or a red, scaly patch on the skin. BCC is the most common type of skin cancer, accounting for about 80% of all cases.
• Squamous cell carcinoma (SCC): A faster-growing cancer that often appears as a firm, red bump or a scaly patch on the skin. SCC can be more aggressive than BCC and has a higher risk of spreading to other parts of the body.

Risk factors for nonmelanoma skin cancer include:

• Overexposure to UV radiation from the sun or tanning beds
• Fair skin, light-colored hair, and blue or green eyes
• A history of sunburns or frequent sun exposure
• A weakened immune system
• A family history of skin cancer
• Exposure to certain chemicals, such as arsenic or coal tar

Treatment for nonmelanoma skin cancer typically involves surgical removal of the cancerous tissue, with the goal of removing all cancer cells while preserving as much healthy tissue as possible. Other treatments, such as radiation therapy, topical chemotherapy, or immunotherapy, may be used in some cases. Prevention of nonmelanoma skin cancer includes avoiding overexposure to UV radiation, wearing protective clothing and sunscreen, and regularly checking the skin for signs of cancer.