What Causes Skin Cancer? Risk Factors Explained

Skin cancer affects over 1.7 million people worldwide each year, making it one of the most common cancers globally. Understanding what causes skin cancer helps you take steps to protect yourself and reduce your risk. While most cases are linked to sun exposure, several other factors play important roles in skin cancer development.

Primary Cause: UV Radiation Exposure

Ultraviolet (UV) radiation is the leading cause of skin cancer. Studies show that 80-95% of all skin cancers result from UV exposure. When UV rays hit your skin, they damage the DNA inside skin cells. Over time, this damage builds up and can cause cells to grow out of control, forming cancer.

UV radiation comes from two main sources:

• Sunlight - The sun emits UVA and UVB rays that penetrate your skin and cause damage

• Tanning beds - Indoor tanning increases melanoma risk, especially for people under 30. Women who tan indoors before age 30 are six times more likely to develop melanoma

The Impact of Sunburns

Sunburns significantly increase skin cancer risk. Research shows that experiencing five or more blistering sunburns between ages 15 and 20 increases your melanoma risk by 80%. Early sun damage has lasting effects, even if you protect your skin later in life.

Skin Type and Pigmentation

Your natural skin characteristics affect your skin cancer risk. Fair skin produces less melanin, the pigment that provides some protection from UV radiation. People with certain features face higher risk:

• Fair skin that burns easily

• Blonde or red hair

• Blue or green eyes

• Freckles or many moles (more than 50)

However, people with darker skin can still develop skin cancer and should also practice sun protection.

Genetic and Family History Factors

Genetics play a role in skin cancer risk. About 5-10% of melanomas run in families. If you have a close family member with skin cancer, your risk increases. Specific gene changes, including variations in the CDKN2A gene, are linked to up to 40% of melanomas in families with a history of the disease.

A personal history of skin cancer also increases your chances of developing another skin cancer. If you've had one basal cell or squamous cell carcinoma, you're more likely to develop another.

Other Risk Factors

Age and Cumulative Sun Exposure

Skin cancer risk increases with age because UV damage accumulates over your lifetime. Most skin cancers appear after age 50, though melanoma can affect younger people, especially those who use tanning beds.

Weakened Immune System

People with weakened immune systems face higher skin cancer risk. This includes organ transplant recipients taking immune-suppressing medications and people with conditions like HIV/AIDS. Your immune system normally helps detect and destroy abnormal cells before they become cancerous.

Prevention: Reducing Your Risk

Since UV exposure causes most skin cancers, prevention focuses on sun protection:

• Apply broad-spectrum sunscreen with SPF 30 or higher daily

• Seek shade during peak sun hours (10 a.m. to 4 p.m.)

• Wear protective clothing, including wide-brimmed hats and UV-blocking sunglasses

• Avoid tanning beds completely

• Perform monthly skin self-exams to check for new or changing spots

When to See a Dermatologist

Schedule an appointment with a dermatologist if you notice any new, changing, or unusual spots on your skin. Early detection dramatically improves treatment outcomes. Get annual skin exams if you have high risk factors like fair skin, many moles, or a family history of skin cancer.

Understanding what causes skin cancer empowers you to make informed decisions about sun protection and screening. While you can't change your genetics or skin type, you can control your UV exposure and significantly reduce your risk.