Skin cancer

Skin cancer occurs when skin cells divide and grow out of control and bind together to form tumors. This abnormal growth often results from damage to the DNA of skin cells caused by excessive UV light exposure, though this isn’t always the case. The main types of skin cancer include:

• Basal cell carcinoma  
• Squamous cell carcinoma
• Melanoma  

Together, basal and squamous cell carcinomas are often referred to as nonmelanoma skin cancer. Less common types of skin cancer include Merkel cell carcinoma, Kaposi sarcoma, and lymphoma of the skin.

How common is skin cancer?

The Skin Cancer Foundation reports that one in five people in the U.S. will develop skin cancer by age 70. And according to the American Cancer Society (ACS), around 5.4 million basal and squamous cell carcinomas are diagnosed in 3.3 million people every year. (Some people develop multiple skin cancers.) About 8 out of 10 of these cases are basal cell carcinomas.

While melanoma makes up just 1 percent of skin cancers, it accounts for most skin cancer deaths. The ACS estimates that more than 97,600 new cases of melanoma will be diagnosed in 2023, while just under 8,000 deaths from this disease are expected within the year. According to the National Cancer Institute (NCI), more than one million people are currently living with melanoma.

Other types of skin cancer are uncommon. For instance, roughly 2,000 cases of Merkel cell carcinoma are diagnosed in the U.S. annually. And out of each million people, there are only around six cases of Kaposi sarcoma diagnosed each year.

Who is most at risk for skin cancer?

Anyone can develop skin cancer, including children, teenagers, and people with dark skin. Still, some individuals have a higher risk of being diagnosed than others. Skin cancer is most common in people with lighter skin, older adults, and people who are frequently exposed to UV light, either from the sun or artificial sources like tanning beds.

Where does skin cancer develop?

Skin cancer develops in the cells of the epidermis (the outermost layer of skin). Different types of skin cancer originate in different skin cells.

• Squamous cell carcinoma begins in the squamous cells—the thin, flat cells that create the top layer of the epidermis, also known as the squamous cell layer.
• Basal cell carcinoma begins in the basal cell layer, or the round cells located beneath the squamous cells.
• Melanoma begins in the melanocyte cells that give skin its pigment and are found in the lowest part of the epidermis.

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As the body’s largest organ, skin is vulnerable to multiple types of cancer, including the following:

Basal cell carcinoma

Basal cell carcinoma (BCC), or basal cell cancer, is the most common type of skin cancer. More than 3.6 million cases are diagnosed in the U.S. every year, according to the Skin Cancer Foundation.

BCC occurs when the skin’s basal cells grow out of control. This skin cancer usually occurs on areas of the body that are frequently exposed to sunlight, such as the face, backs of the ears, and neck. It tends to develop slowly and rarely metastasizes (spreads) to other areas of the body, although untreated basal cell carcinoma can grow deeply into surrounding tissues and cause disfigurement.   

This type of skin cancer is highly treatable and rarely deadly. However, BCC that is not fully removed can recur in the same location, and it’s common for people to develop multiple BCCs over the course of their lifetimes.

Squamous cell carcinoma

Squamous cell carcinoma (SCC), also known as squamous cell cancer or cutaneous squamous cell carcinoma, is the second most common type of skin cancer overall and the most common in Black people. It occurs when squamous cells grow abnormally fast. The Skin Cancer Foundation reports that an estimated 1.8 million cases of squamous cell carcinoma are diagnosed in the U.S. every year, and rates have increased as much as 200 percent in the last 30 years.

Squamous cell carcinoma tends to develop on parts of the body that are exposed to the sun, such as the back of the hands, face, ears, and lips. It’s also possible for SCC to occur in scars or on areas of the body that are normally covered, including the genitals.

In some cases, SCC develops from precancerous skin conditions such as:

• Actinic keratosis (solar keratosis): A common skin disorder that results in scaly, rough patches of skin.
• Bowen disease (squamous cell carcinoma in situ): A rare skin disorder characterized by slow-growing, reddish growths.
• Leukoplakia: Thick, white patches or spots that can develop inside the mouth, including the tongue, gums, inside of the cheeks, and base of the mouth.

While squamous cell carcinoma isn’t a fast-growing skin cancer, it’s more likely to spread and become life-threatening than basal cell carcinoma. Many cases of SCC are easily treated, especially when diagnosed in an early stage.

Melanoma

Melanoma is the deadliest form of skin cancer, although early detection and treatment leads to positive outcomes in many cases. The NCI reports that the five-year relative survival rate (the average percentage of people still alive five years after their diagnosis) for melanoma is 94 percent.  

Melanoma can occur anywhere on the body, including the mouth, eyes, genitals, bottoms of the feet, palms of the hands, and in nailbeds. Still, it’s most likely to develop on the:

• Face
• Neck
• Chest
• Back
• Legs

People assigned male at birth are prone to experiencing melanoma on their chests and backs, while people assigned female at birth are more likely to have melanoma on their legs, according to the ACS.

Despite popular belief that most melanomas grow out of existing moles, the Skin Cancer Foundation reports that 70 to 80 percent of melanomas form on regular skin. Melanoma tends to spread quickly, so it’s important to promptly speak with a healthcare provider (HCP) if you notice any unusual changes to your skin or to existing moles you might have.

Merkel cell carcinoma

A Merkel cell is a type of neuroendocrine cell that’s found at the base of the epidermis. (The neuroendocrine system involves the body’s nervous and hormonal systems.) These cells are located near nerve endings, which help people sense and respond to touch. When Merkel cells grow out of control, Merkel cell carcinoma (sometimes called MCC or Merkel cell skin cancer) can occur.

Merkel cell carcinoma is an uncommon and aggressive cancer that’s three to five times more deadly than melanoma. Still, it’s curable with early detection and treatment. Most Merkel cell carcinomas develop on the face, neck, and arms, although they can grow anywhere on the body.

Kaposi sarcoma

Kaposi sarcoma is a rare skin cancer that forms in endothelial cells that line the blood and lymph vessels. Many cases of Kaposi sarcoma in the U.S. are related to the human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS). Treatment for these cases typically involves a combination of anti-HIV drugs.

Kaposi sarcoma can cause tumors on the skin or inside the mouth, along with discolored blotches on the face, legs, or groin area. It’s also possible for Kaposi sarcoma to occur in the digestive tract, lungs, or the lymph nodes. (Lymph nodes are small, bean-shaped glands located throughout the body that help filter out and eliminate foreign substances such as cancer cells and other infectious or harmful agents.) 

Lymphoma of the skin

Lymphoma of the skin is an uncommon type of non-Hodgkin lymphoma (NHL). It’s sometimes called cutaneous lymphoma. Skin lymphomas account for just 4 percent of all NHL cases, according to the ACS. When diagnosed in an early stage, skin lymphoma is usually easily treated.

NHL is a type of lymphoma, a form of cancer that begins in white blood cells known as lymphocytes. These immune system cells are present in skin and other lymph tissues, including the spleen and bone marrow. Lymphoma of the skin refers to cancer that originates in lymphocytes located in the skin.

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The appearance of skin cancer can vary from person to person, so it’s important to speak with an HCP if you notice any unusual changes in your skin. Still, there are general signs and symptoms that may point to the presence of skin cancer.

Basal cell carcinoma symptoms

Basal cell carcinoma can appear as a/an:

• Reddish or discolored raised patch that might be itchy
• Open sore that doesn’t heal, or heals and comes back
• Unusually pale or yellow area that may resemble a scar
• Pinkish growth with raised edges and a cratered center
• Small bump that may appear shiny, pink, red, or translucent, sometimes with brown, black, or bluish areas

In people with dark skin, basal cell carcinomas may be pigmented and appear dark brown.

This type of skin cancer may also bleed easily, ooze liquid, or crust over. Often, shaving over a BCC can cause it to bleed. Most shaving cuts heal within a week, so it’s a good idea to speak with an HCP if such an injury hasn’t improved in seven days or so.

Squamous cell carcinoma symptoms

Squamous cell carcinoma can appear as a/an:

• Red or discolored rough, scaly patch that may scab, ooze, or bleed
• Open sore that doesn’t heal, or heals and comes back
• Wart-like growth
• Raised bump or growth that’s lower in the center

Often, the signs of squamous cell carcinoma are very subtle. Skin changes related to SCC may also occur in existing sores or scars. In people with dark skin, SCC tends to appear as an open sore or a raised, wart-like growth.

Melanoma symptoms

The main warning sign of melanoma is a new spot on the skin or an existing mole that changes shape, color, or size. Another possible symptom of melanoma is a spot on your skin that looks different from any other moles or discolorations you may have. (This is sometimes called an “ugly duckling” sign.)  

The most common type of melanoma in people of color is acral lentiginous melanoma (ALM), which can present as a dark spot on the palms of the hands, soles of the feet, or underneath nails. 

Many HCPs encourage people to follow the “ABCDE” rule to help differentiate melanomas from noncancerous moles, birthmarks, and other discolorations.

• Asymmetry (A): Many melanomas are asymmetrical, meaning one half of the spot doesn’t match the other. 
• Border (B): Melanomas tend to have scalloped, jagged, or uneven borders, while noncancerous growths may be perfectly round.
• Color (C): Many melanomas feature various shades of black or brown, sometimes with spots of blue, pink, red, or white.
• Diameter (D): A key indicator of melanoma is a diameter (or crosswise width) that’s about the size of a pencil eraser or larger. (That said, you should still speak with an HCP if you notice an unusual growth that’s smaller than a pencil eraser.) 
• Evolving (E): Most melanomas gradually evolve in shape, size, or color over time.

If melanoma spreads to other areas of the body, symptoms may include:

• Swollen lymph nodes
• Unexplained pain or weight loss
• Fatigue 
• Yellowing of skin or eyes (jaundice)
• Buildup of fluid in the abdominal area 
• Stomach pain

Merkel cell carcinoma symptoms

The signs of Merkel cell carcinoma can vary, but this skin cancer typically appears as a shiny, pimple-like bump that may be red, bluish, purple, or skin-colored. This bump will grow quicklyand usually isn’t painful or tender. Over time, the cancer can spread to nearby lymph nodes and may be felt or seen as lumps beneath the skin.

Kaposi sarcoma symptoms

Kaposi sarcoma usually appears as a fast-growing lesion (an abnormal spot on the skin) that may be purple, red, brown, blue, or black. It often develops on the face or legs but can also occur inside the mouth. Lesions usually aren’t painful or itchy. The discolored lesion may look like a:

• Flat patch
• Slightly raised patch (also called a plaque)
• Bump (also known as a nodule)

If Kaposi sarcoma lesions develop inside the body, symptoms can involve:

• Shortness of breath
• Chest pain
• Abdominal pain
• Diarrhea 
• Coughing that produces blood

Skin lymphoma symptoms

The appearance of skin lymphoma can vary based on what specific type of lymphoma is present. Possible signs of skin lymphoma may include:

• Small, pimple-like bumps
• Flat patches that look like a rash
• Plaques
• Nodules or tumors that can be felt beneath the skin

These growths can be itchy, scaly, brown, red, or purple and may break open and ooze fluid. Although uncommon, other symptoms of skin lymphoma may include:

• Swollen lymph nodes
• Fever
• Fatigue
• Unexplained weight loss
• Heavy sweating, especially at night
• Intense itchiness

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It’s important to consult with an HCP if you notice any unusual sores, moles, blemishes, lumps, markings, or other changes in the way your skin looks or feels—even if your symptoms don’t perfectly match any of the descriptions above.

Skin cancer affects people in different ways and can vary in appearance. Changes in your skin could also indicate noncancerous conditions that require treatment, such as the chronic skin condition psoriasis, the viral infection shingles, and bacterial infections like methicillin-resistant Staphylococcus aureus (MRSA).

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Skin cancer occurs when the DNA of skin cells becomes damaged. Essentially, DNA tells cells how to function in a healthy way. Damage to DNA can cause cells to grow out of control and form malignant (cancerous) tumors or lesions.

The main cause of this DNA damage is too much exposure to UV light from the sun or artificial sources like tanning beds and sun lamps. UV light is a type of electromagnetic radiation emitted by light sources.

Other factors such as genetics, underlying medical conditions, and exposure to toxic substances like arsenic can also play a role in skin cancer development. This is especially true for skin cancers that develop in areas of the body that are usually protected from the sun, such as the genitals.

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Certain factors increase your risk for skin cancer, although anyone can develop it.

UV light exposure

Unprotected and prolonged exposure to natural or artificial UV light is the biggest risk factor for skin cancer. In fact, according to the Skin Cancer Foundation, having a history of just five or more sunburns doubles your risk of melanoma. A sunburn is your body’s inflammatory response to too much UV radiation.

Even if you don’t burn easily in the sun (for example, you have dark skin or you tan well), UV light can still damage your skin and increase your risk of skin cancer. This is especially true if you’re frequently outdoors or live in a high-altitude area where the sun’s rays tend to be more powerful.

With this in mind, a small daily dose of natural sunlight, such as what you’d get from an outdoor nature walk, can have its benefits. The Centers for Disease Control and Prevention (CDC) says spending some time outdoors can improve your mental health and help reduce stress. Just be sure to put on protective clothing and thoroughly apply (and re-apply) a broad-spectrum sunscreen with a sun protection factor (SPF) of 15 or higher. If possible, relax in a shaded or covered area instead of in the direct sunlight to get more protection from UV rays.

Moles

Having a lot of moles—or large moles with irregular borders called dysplastic nevi—can leave you more vulnerable to skin cancer. Keep a close eye on your moles and promptly speak with an HCP if you notice unusual changes or new growths developing.

Fair skin and light hair

People with these characteristics generally have a higher risk of skin cancer than those with darker complexions. This is because fair-skinned people have less melanin, a pigment that gives skin its color and helps protect against damaging UV rays.

Family history of skin cancer

You may have an increased risk of skin cancer if a closely related blood relative such as a parent, sibling, or child has been diagnosed. For example, melanoma may occur more often among biologically related family members.

Weakened immune system

Having a weakened immune system can increase your risk of skin cancer. Several factors can lead to a compromised immune system, including:

• Taking an immunosuppressant medication after receiving an organ transplant or as treatment for an autoimmune condition
• Having HIV/AIDS
• Receiving chemotherapy to treat another type of cancer

Older age

In general, older adults are more prone to skin cancer than younger people. People assigned female at birth are more likely to be diagnosed with skin cancer before age 50 than people assigned male at birth. Additionally, people of color are typically diagnosed with skin cancer at older ages, which can make effective treatment more difficult.

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An HCP may perform a skin exam as part of a routine physical or checkup. If your HCP spots an unusual-looking mole or growth, they may refer you to a dermatologist (a doctor who specializes in identifying and treating skin conditions) or order a skin biopsy. During a skin biopsy, a small amount of tissue is removed from the area in question and analyzed for cancerous cells under a microscope. This test can also determine what type of skin cancer is present (for example, melanoma or basal cell carcinoma).  

The next step after a skin cancer diagnosis is to stage the cancer, that is, to determine how much cancer is in your body and if it has spread. To do this, tests such as a sentinel lymph node biopsy may be performed. (A sentinel lymph node biopsy involves the removal and examination of a nearby lymph node.)

Imaging tests like computed tomography (CT) scans and positron emission tomography (PET) scans may also be used to screen for cancer that has traveled to other parts of the body. Basal cell carcinomas rarely spread, so additional testing is most often performed in people diagnosed with melanoma, Merkel cell carcinoma, or a large squamous cell carcinoma.

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Skin cancer is staged from 0 to 4. Stage 0 refers to cancer that is confined to the uppermost layer of skin, while stage 4 describes cancer that has spread to distant areas of the body.  

Melanoma—which is more likely to spread than nonmelanoma cancers—is staged according to the following criteria:

• Stage 0 (known as melanoma in situ): Cancer is only present in the very top layer of skin
• Stage 1: Cancer is present but has not spread
• Stage 2: Cancer displays features that suggest it could spread or recur after treatment, but there’s no evidence of spread
• Stage 3: Cancer has spread to nearby lymph nodes or other areas of skin
• Stage 4: Cancer has spread to internal organs or distant lymph nodes

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Many skin cancers are highly treatable, especially when they’re diagnosed in an early stage. Depending on what type of skin cancer you have, its stage, and factors like your overall health, your skin cancer treatment plan may include a combination of the following:

Excision surgery

During a simple excision surgery, the skin cancer and a small amount of surrounding healthy tissue is removed. In a shave excision procedure, a small blade is used to shave away a cancerous part of the skin.

Curettage and electrodesiccation

Also referred to as electrosurgery, curettage and electrodesiccation involves two steps:

• A sharp, spoon-like instrument called a curette is used to cut the cancer out of the skin.
• A needle-shaped instrument called an electrode then sends a gentle electrical current to the wound to help stop bleeding and destroy any remaining cancer cells. This step may be repeated one to three times, depending on the size of the cancer.

Mohs micrographic surgery

Mohs micrographic surgery involves carefully removing skin cancer layer by layer until no cancer remains. Each removed layer is examined under a microscope to check for cancerous cells. The procedure is complete once the surgeon removes a layer that’s free of cancer cells.

The goal of Mohs surgery is to remove as little healthy skin as possible. It’s often recommended for people with skin cancer on their face, fingers, or genital area.

Cryotherapy

Cryotherapy—also known as cryosurgery—is a surgical procedure that uses liquid nitrogen to freeze off small cancers and treat precancerous conditions, such as actinic keratosis.

Photodynamic therapy

Photodynamic therapy uses a combination of laser light and a light-activated drug to destroy skin cancer cells. During treatment, the drug is applied directly to the skin cancer or injected into a vein. Cancer cells absorb the drug and are destroyed once the area is exposed to  laser light.

Chemotherapy

Chemotherapy uses anti-cancer medications to destroy cancer cells or stop their growth. When used as skin cancer treatment, chemotherapy may be given in the form of a topical cream or lotion that’s applied directly to the affected area. In other cases, chemotherapy is administered through an intravenous (IV) line to reach cancer cells that have spread beyond the skin.

Radiation therapy

Radiation therapy is sometimes used to treat skin cancer that can’t be completely removed through surgery. During treatment, high-powered energy beams are aimed precisely at an area of skin to destroy cancer cells.

Immunotherapy

Immunotherapy helps identify and treat skin cancer by using the body’s own immune system. Different types of immunotherapy drugs are used to target different types of skin cancer and disrupt the processes that contribute to their growth.

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Any medicine or medical procedure comes with some measure of risk. When it comes to skin cancer treatment, possible complications include:

• Nausea, vomiting, diarrhea, or hair loss (related to chemotherapy)
• Skin scarring
• Hypopigmentation (loss of skin pigment) or hyperpigmentation (skin that appears darker than surrounding skin)
• Skin infection, including a severe and potentially life-threatening infection called sepsis
• Loss of feeling due to nerve damage
• Lymphedema (swelling that can occur in the arms or legs when lymph nodes are damaged or removed)

Talk with your HCP if you have questions about possible skin cancer treatment side effects or about finding the best treatment option for your needs. If you experience unexpected side effects during treatment, let your HCP know as soon as possible.

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It’s not possible to definitively prevent any type of cancer. Nevertheless, you can significantly lower your risk of skin cancer by avoiding indoor tanning and following some simple sun safety guidelines. When enjoying the outdoors, the CDC encourages you to:

• Spend time in the shade when possible.
• Thoroughly apply a broad-spectrum sunscreen with an SPF of 15 or higher and reapply throughout the day.
• Wear a wide-brimmed hat that shades your neck, ears, scalp, and face.
• Cover your arms and legs with protective clothing (for example, clothing with tightly woven fabric or built-in UV protection). 
• Wear wraparound sunglasses that block both UVA and UVB rays (two different types of UV light). 

It’s also good to know if any medications you’re taking increase your sensitivity to the sun (called photosensitivity) and raise your risk of sunburn. These medications can include, but aren’t limited to:

• Antibiotics (such as ciprofloxacin, co-trimoxazole, dapsone, and tetracycline)
• Antifungal medication (such as griseofulvin) 
• Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) (such as ibuprofen, ketoprofen, and naproxen) 
• Diuretics, which help rid the body of excess fluid and salt (such as furosemide and hydroxychloroquine)  

Finally, one of the best ways to prevent skin cancer is to regularly check your skin and promptly speak with an HCP if you notice any unusual changes, no matter how small they may seem. Identifying and treating a precancerous skin condition can stop skin cancer before it even starts.

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Skin cancer can be deadly, but most cases are treatable. In fact, death from basal cell carcinoma or squamous cell carcinoma is uncommon and typically occurs in people who are older or have an underlying health concern, such as a weakened immune system.  

The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) database tracks relative five-year survival rates for skin cancers like melanoma and Merkel cell carcinoma. It follows survival rates based on stages labeled as:

• Localized: Cancer has not spread beyond the skin where it began.
• Regional: Cancer has spread to nearby lymph nodes or other structures.
• Distant: Cancer has spread to distant parts of the body.

Melanoma is responsible for most skin cancer deaths. Still, the relative five-year survival rate for all SEER stages of melanoma combined is 94 percent. When broken down by stage at diagnosis, the five-year survival rates are:

• 99 percent for localized melanoma
• 71 percent for regional melanoma
• 32 percent for distant melanoma

The relative five-year survival rate for all SEER stages of Merkel cell carcinoma combined is 65 percent. By stage at diagnosis, five-year survival rates are:

• 75 percent for localized Merkel cell carcinoma
• 61 percent for regional Merkel cell carcinoma
• 24 percent for distant Merkel cell carcinoma

As the statistics indicate, early diagnosis is key to a positive outcome in many instances. But it’s important to remember that these figures reflect the survival rate of people diagnosed between 2012 and 2018, and they don’t account for individual factors such as age at diagnosis, overall health, and the location of skin cancer. As treatment options for skin cancer continue to improve, so will the outlook for this condition.

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Living with cancer presents unique physical and emotional challenges. Implementing healthy lifestyle choices and relying on friends, family, and loved ones for support can improve your overall well-being as you go through treatment and focus on healing.   

In addition to carefully following your HCP’s skin cancer treatment guidance, it may help to:

• Avoid or quit smoking
• Exercise regularly, if you’re able.
• Limit alcohol intake.
• Take steps to manage your stress.
• Eat a balanced, nutrient-rich diet.  
• Make time for fun, whether that’s going on a weekend getaway, watching your favorite movie, or attending a yoga class.

Spending time outdoors can help improve your mood and reduce stress, but it’s important to be mindful of your skin health as you go through treatment. Try participating in outdoor activities before 10 a.m. or after 4 p.m. to avoid strong sunlight, and always wear broad-spectrum SPF sunscreen and protective clothing when outside.

Cancer is more than skin deep. Skin cancer can affect your mental health in profound ways, from feeling shocked and surprised to experiencing anxiousness, sadness, or frustration. Spending time with loved ones, speaking to a licensed mental health provider, or joining an online or in-person cancer support group can help you navigate your emotions and enhance your quality of life after a skin cancer diagnosis.

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• Systemic Therapies for Cutaneous Squamous Cell Carcinoma
• Know Before You Go: Skin Biopsy
• 5 Skin Spots and What They May Mean