Skin Cancer

 

Overview

Skin cancer, or the abnormal proliferation of skin cells, is most commonly found on sun-exposed skin. However, this frequent type of cancer can also develop on parts of your skin that aren't normally exposed to the sun.

Basal cell carcinoma, squamous cell carcinoma, and melanoma are the three most common kinds of skin cancer.

Limiting or avoiding ultraviolet (UV) radiation exposure can lower your risk of skin cancer. Skin cancer can be detected at an early stage if you check your skin for abnormal changes. Early skin cancer detection increases your chances of a successful skin cancer treatment.

Symptoms

Where skin cancer develops

Skin cancer is most commonly found in sun-exposed regions of the body, such as the scalp, face, lips, ears, neck, chest, arms, and hands, as well as the legs in women. However, it can also occur in locations that are rarely exposed to the sun, such as your palms, under your fingernails or toenails, and your genital area.

People of all skin tones, particularly those with darker complexions, are susceptible to skin cancer. Melanoma is more prone to develop in places not ordinarily exposed to the sun, such as the palms of the hands and the soles of the feet, in people with dark skin tones.

Basal cell carcinoma signs and symptoms

Basal cell carcinoma is most common in parts of the body that are exposed to the sun, such as the neck and face.

Basal cell carcinoma can take the following forms:

• A waxy or pearly lump
• A scar-like lesion that is flat, flesh-colored, or brown.
• A scabbing or bleeding sore that heals and reappears

Symptoms and indications of squamous cell carcinoma

Squamous cell carcinoma is most commonly found on sun-exposed parts of the body, such as the face, ears, and hands. Squamous cell carcinoma is more likely to develop on parts of the skin that aren't frequently exposed to the sun in people with darker skin.

Squamous cell carcinoma may appear as:

• A firm, red nodule
• A flat lesion with a scaly, crusted surface

Melanoma signs and symptoms

Melanoma can appear anywhere on your body, in otherwise healthy skin or as a malignant mole in an existing mole. Melanoma more commonly occurs on the face or trunk of men who are affected. This form of cancer most commonly affects women's lower legs. Melanoma can develop on skin that hasn't been exposed to the sun in both men and women.

Melanoma can strike anyone with any skin tone. Melanoma is more common in the palms and soles of those with darker skin tones, as well as under the fingernails and toenails.

Melanoma signs include:

• A large brownish spot with darker speckles
• A mole that changes in color, size, or feels or that bleeds
• A small lesion with an irregular border and portions that appear red, pink, white, blue, or blue-black
• A painful lesion that itches or burns
• Dark lesions on your palms, soles, fingertips or toes, or on mucous membranes lining your mouth, nose, vagina, or anus

Signs and symptoms of less common skin cancers

Other, less common types of skin cancer include:

• Kaposi sarcoma. This rare form of skin cancer develops in the skin's blood vessels and causes red or purple patches on the skin or mucous membranes.

  Kaposi sarcoma mainly occurs in people with weakened immune systems, such as people with AIDS, and in people taking medications that suppress their natural immunity, such as people who've undergone organ transplants.

  Other people with an increased risk of Kaposi sarcoma include young men living in Africa or older men of Italian or Eastern European Jewish heritage.

• Merkel cell carcinoma. Merkel cell carcinoma causes firm, shiny nodules that occur on or just beneath the skin and in hair follicles. Merkel cell carcinoma is most often found on the head, neck, and trunk.
• Sebaceous gland carcinoma. This uncommon and aggressive cancer originates in the oil glands in the skin. Sebaceous gland carcinomas — which usually appear as hard, painless nodules — can develop anywhere, but most occur on the eyelid, where they're frequently mistaken for other eyelid problems.

When to see a doctor

Make an appointment with your doctor if you notice any changes to your skin that worry you. Not all skin changes are caused by skin cancer. Your doctor will investigate your skin changes to determine a cause.

Causes

Skin cancer occurs when errors (mutations) occur in the DNA of skin cells. The mutations cause the cells to grow out of control and form a mass of cancer cells.

Cells involved in skin cancer

Skin cancer begins in your skin's top layer — the epidermis. The epidermis is a thin layer that provides a protective cover of skin cells that your body continually sheds. The epidermis contains three main types of cells:

• Squamous cells lie just below the outer surface and function as the skin's inner lining.
• Basal cells, which produce new skin cells, sit beneath the squamous cells.
• Melanocytes — which produce melanin, the pigment that gives skin its normal color — are located in the lower part of your epidermis. Melanocytes produce more melanin when you're in the sun to help protect the deeper layers of your skin.

Where your skin cancer begins determines its type and your treatment options.

Ultraviolet light and other potential causes

Much of the damage to DNA in skin cells results from ultraviolet (UV) radiation found in sunlight and in the lights used in tanning beds. But sun exposure doesn't explain skin cancers that develop on skin not ordinarily exposed to sunlight. This indicates that other factors may contribute to your risk of skin cancer, such as being exposed to toxic substances or having a condition that weakens your immune system.

Risk factors

Factors that may increase your risk of skin cancer include:

• Fair skin. Anyone, regardless of skin color, can get skin cancer. However, having less pigment (melanin) in your skin provides less protection from damaging UV radiation. If you have blond or red hair and light-colored eyes, and you freckle or sunburn easily, you're much more likely to develop skin cancer than a person with darker skin.
• A history of sunburns. Having had one or more blistering sunburns as a child or teenager increases your risk of developing skin cancer as an adult. Sunburns in adulthood also are a risk factor.
• Excessive sun exposure. Anyone who spends considerable time in the sun may develop skin cancer, especially if the skin isn't protected by sunscreen or clothing. Tanning, including exposure to tanning lamps and beds, also puts you at risk. A tan is your skin's injury response to excessive UV radiation.
• Sunny or high-altitude climates. People who live in sunny, warm climates are exposed to more sunlight than are people who live in colder climates. Living at higher elevations, where the sunlight is strongest, also exposes you to more radiation.
• Moles. People who have many moles or abnormal moles called dysplastic nevi are at increased risk of skin cancer. These abnormal moles — which look irregular and are generally larger than normal moles — are more likely than others to become cancerous. If you have a history of abnormal moles, watch them regularly for changes.
• Precancerous skin lesions. Having skin lesions known as actinic keratoses can increase your risk of developing skin cancer. These precancerous skin growths typically appear as rough, scaly patches that range in color from brown to dark pink. They're most common on the face, head, and hands of fair-skinned people whose skin has been sun-damaged.
• A family history of skin cancer. If one of your parents or a sibling has had skin cancer, you may have an increased risk of the disease.
• A personal history of skin cancer. If you developed skin cancer once, you're at risk of developing it again.
• A weakened immune system. People with weakened immune systems have a greater risk of developing skin cancer. This includes people living with HIV/AIDS and those taking immunosuppressant drugs after an organ transplant.
• Exposure to radiation. People who received radiation treatment for skin conditions such as eczema and acne may have an increased risk of skin cancer, particularly basal cell carcinoma.
• Exposure to certain substances. Exposure to certain substances, such as arsenic, may increase your risk of skin cancer.

Prevention

Most skin cancers are preventable. To protect yourself, follow these skin cancer prevention tips:

• Avoid the sun during the middle of the day. For many people in North America, the sun's rays are strongest between about 10 a.m. and 4 p.m. Schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy.

  You absorb UV radiation year-round, and clouds offer little protection from damaging rays. Avoiding the sun at its strongest helps you avoid the sunburns and suntans that cause skin damage and increase your risk of developing skin cancer. Sun exposure accumulated over time also may cause skin cancer.

• Wear sunscreen year-round. Sunscreens don't filter out all harmful UV radiation, especially the radiation that can lead to melanoma. But they play a major role in an overall sun protection program.

  Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Apply sunscreen generously, and reapply every two hours — or more often if you're swimming or perspiring. Use a generous amount of sunscreen on all exposed skin, including your lips, the tips of your ears, and the backs of your hands and neck.

• Wear protective clothing. Sunscreens don't provide complete protection from UV rays. So cover your skin with dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than a baseball cap or visor does.

  Some companies also sell photoprotective clothing. A dermatologist can recommend an appropriate brand.

  Don't forget sunglasses. Look for those that block both types of UV radiation — UVA and UVB rays.

• Avoid tanning beds. Lights used in tanning beds emit UV rays and can increase your risk of skin cancer.

• Be aware of sun-sensitizing medications. Some common prescription and over-the-counter drugs, including antibiotics, can make your skin more sensitive to sunlight.

  Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, take extra precautions to stay out of the sun in order to protect your skin.

• Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps, and birthmarks.

  With the help of mirrors, check your face, neck, ears, and scalp. Examine your chest and trunk, and the tops and undersides of your arms and hands. Examine both the front and back of your legs and your feet, including the soles and the spaces between your toes. Also, check your genital area and between your buttocks.

SOURCE mayoclinic.org