Skin cancer is the most common type of cancer, primarily caused by the uncontrolled growth of abnormal skin cells. It typically develops on skin exposed to the sun but can also occur on areas not ordinarily exposed to sunlight. There are three main types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma, with melanoma being the most serious due to its tendency to spread to other parts of the body.

Types of Skin Cancer

• Basal Cell Carcinoma (BCC): The most common type, usually appears as a pearly or waxy bump on sun-exposed areas like the face and neck.
• Squamous Cell Carcinoma (SCC): Often appears as a firm, red nodule or a flat lesion with a scaly, crusted surface, commonly on the face, ears, neck, and hands.
• Melanoma: The most aggressive form, can develop anywhere on the body. It often appears as a large brownish spot with darker speckles or as a mole that changes in color, size, or feel.

Causes and Risk Factors
Several factors can increase the risk of developing skin cancer, including:

• Ultraviolet (UV) Radiation: The primary cause, mainly from sunlight and tanning beds.
• Fair Skin: Less melanin makes the skin more susceptible to damage from UV radiation.
• History of Sunburns: Especially during childhood or adolescence.
• Excessive Sun Exposure: Spending a lot of time outdoors without protective clothing or sunscreen.
• Living in Sunny or High-Altitude Climates: More exposure to UV radiation.
• Moles: Having many moles or unusual moles (dysplastic nevi) increases the risk of melanoma.
• Family History: A family history of skin cancer increases risk.
• Weakened Immune System: Conditions that weaken the immune system, such as HIV/AIDS, or medications that suppress the immune system.
• Exposure to Certain Substances: Exposure to chemicals such as arsenic.

Symptoms
The symptoms of skin cancer vary depending on the type but often include:

• Basal Cell Carcinoma: A pearly or waxy bump, flat flesh-colored or brown scar-like lesion.
• Squamous Cell Carcinoma: A firm, red nodule, or a flat lesion with a scaly, crusted surface.
• Melanoma: A large brownish spot with darker speckles, a mole that changes in color, size, or feel, or that bleeds, a small lesion with an irregular border and parts that appear red, pink, white, blue, or blue-black.

Diagnosis
Diagnosis of skin cancer involves several steps and tests, including:

• Skin Examination: A doctor examines the skin for suspicious changes.
• Biopsy: Removing a small sample of skin for laboratory testing to determine if it is cancerous and, if so, the type and stage of cancer.

Treatment Options
Treatment for skin cancer depends on the type, size, location, and stage of the cancer. Options include:

• Surgery: Removing the cancerous tissue. Different techniques include excisional surgery, Mohs surgery (layer-by-layer removal), and curettage and electrodesiccation (scraping and burning the cancer cells).
• Radiation Therapy: Using high-energy rays to kill cancer cells, often used when surgery is not an option.
• Cryotherapy: Freezing cancer cells with liquid nitrogen.
• Topical Treatments: Creams or ointments for superficial skin cancers.
• Photodynamic Therapy: Using light and photosensitizing agents to destroy cancer cells.
• Chemotherapy: Topical or systemic drugs to kill cancer cells, usually for advanced cases.
• Targeted Therapy: Drugs that specifically target cancer cell mechanisms, often used for advanced melanoma.
• Immunotherapy: Boosts the immune system to fight cancer, particularly useful for advanced melanoma.

Prevention and Monitoring
Preventing skin cancer involves several strategies:

• Avoiding Excessive Sun Exposure: Especially between 10 a.m. and 4 p.m.
• Wearing Protective Clothing: Hats, sunglasses, and long sleeves.
• Using Sunscreen: Broad-spectrum sunscreen with an SPF of at least 30, applied regularly.
• Avoiding Tanning Beds: Artificial UV radiation increases the risk of skin cancer.
• Regular Skin Checks: Both self-examinations and professional skin exams to detect any new or changing lesions early.