Skin Cancer

Main

Skin cancer is the most commonly diagnosed cancer in humans, accounting for at least 40% of cancer cases globally. It develops primarily on sun-exposed areas like the face, ears, neck, and hands, but can also occur on less exposed areas. Ultraviolet (UV) radiation from the sun or tanning beds causes over 90% of cases by damaging DNA and triggering mutations that lead to uncontrolled cell growth. For example, spending long hours in the sun without protection significantly increases skin cancer risk.

Types of skin cancer:

1. Basal cell carcinoma (BCC): The most common type, arising from the skin's basal cells in the epidermis. It appears as a painless, shiny, flesh-colored or pink bump. BCC rarely spreads and has a high cure rate with early treatment.

2. Squamous cell carcinoma (SCC): The second most common type, arising from the squamous cells in the epidermis. Appears as a firm bump with a scaly surface. SCC can spread if left untreated but is highly curable when caught early.

3. Melanoma: The most aggressive type, developing from pigment-producing cells called melanocytes. Often resembles an abnormal mole that has changed in size, shape or color. Melanoma can spread quickly but is highly treatable when detected early.

Causes of skin cancer:

• UV radiation from the sun or tanning beds

• Weakened immune system

• Exposure to certain chemicals or radiation

Factors that increase skin cancer risk:

• Fair skin, light hair, and eye color

• Family history of skin cancer

• Multiple or atypical moles

• History of sunburns, especially in childhood

Features of skin cancer:

• Changes in the appearance of moles, freckles, or other skin marks

• Asymmetry, border irregularity, color variability, and diameter larger than 6mm (ABCD rule for melanoma)

• Itching, bleeding, or crusting of a skin lesion

• Sores that don't heal

Treatment for skin cancer depends on the type, size, depth, and location of the lesion. Options include surgical excision, Mohs surgery, radiation therapy, chemotherapy, and targeted therapy. Survival rates are high when skin cancer is detected and treated early, with 5-year survival rates of 99% for BCC and 97% for SCC. Melanoma survival varies based on stage at diagnosis, from 99% for localized to 30% for distant stage.

Terms

• Cancer: A disease in which abnormal cells divide uncontrollably and can invade nearby tissues and spread to other parts of the body through the blood and lymph systems.

• DNA: Deoxyribonucleic acid, the hereditary material in humans and almost all other organisms. UV radiation can damage DNA, leading to mutations that cause skin cancer.

• Nonmelanoma skin cancer: Refers to all types of skin cancer that are not melanoma, primarily BCC and SCC.

Analogy

Skin cancer is like weeds in a garden. Just as weeds grow uncontrollably and take over a garden when left unchecked, cancer cells multiply rapidly and form tumors when DNA damage goes unrepaired. For instance, a small patch of weeds can spread and overtake an entire flowerbed if not removed early.

Misconception

Many people believe that only those with fair skin are at risk for skin cancer. However, skin cancer affects people of all skin tones, even those with darker complexions. While individuals with light skin are at higher risk, anyone can develop skin cancer, especially with frequent sun exposure. For example, Bob, who has dark skin, assumed he was not at risk and frequently worked outdoors without sun protection, later developing melanoma.

History

1. 1804: The first description of melanoma as a disease

2. 1956: Henry Lancaster quantifies the link between sun exposure and skin cancer

3. 1979: The FDA first proposes testing and rating sunscreens for UV protection

4. 1996: The FDA approves the first treatment for advanced melanoma

5. 2011: The FDA approves vemurafenib, the first targeted therapy for melanoma

How to use it

1. Check your skin regularly for new or changing spots, sores, bumps or patches. Note any that change in size, shape or color. See a dermatologist yearly for a professional skin exam.

2. Protect your skin when outdoors, even on cloudy days. Wear broad-spectrum sunscreen of at least SPF 30, protective clothing, a wide-brimmed hat, and sunglasses. Seek shade during peak sun hours.

3. Avoid tanning beds and sunlamps, which emit harmful UV rays that damage skin and increase skin cancer risk. Self-tanning lotions are a safer alternative for achieving a bronzed look.

Facts

• 1 in 5 Americans will develop skin cancer by age 70

• More than 2 people die of skin cancer every hour in the U.S.

• Having 5 or more sunburns doubles your melanoma risk

• Indoor tanning increases SCC risk by 67% and BCC risk by 29%

• Skin cancer treatment costs over $8 billion annually in the U.S.