Skin Cancer: An Overview

Medically Reviewed by Poonam Sachdev on March 13, 2024
Written by Rachel Reiff Ellis
15 min read

Skin cancer -- the uncontrolled growth of abnormal cells in your skin -- is the most common of all human cancers. About 1 in 5 Americans will get some type of skin cancer in their lifetime, and more than two people die of skin cancer every hour in the U.S. Skin cancer affects people of all skin colors.  

Recent studies show the number of skin cancer cases in the U.S. growing at an alarming rate. Fortunately, increased awareness on the part of Americans and their health care providers has resulted in earlier diagnosis and improved outcomes.

There are three major types of skin cancers: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. The first two skin cancers are grouped together as nonmelanoma skin cancers. 

Basal cell carcinoma

This is the most common type of skin cancer. Typically you get this type of cancer after years of sun exposure. You can get BCC anywhere, but it’s most common on the head, neck, and arms. 

Although this type is malignant (it grows uncontrollably), it's unlikely to spread to other parts of the body if you treat it early. 

Squamous cell carcinoma

SCC is the second most common type of skin cancer. People with fair skin are at the highest risk of getting it, but it can happen to anyone of any skin color. You’re mostly likely to see it on the rim of your ear, face, neck, arms, chest, and back.

Melanoma

Melanomas make up a slightly smaller number of skin cancer cases than BCC or SCC, but malignant melanoma is much more aggressive and tends to spread to other parts of the body. These cancers may be fatal if they don’t get early treatment. Melanoma can grow out of a mole you already have on your body, or appear as a dark spot on your skin. 

Merkel cell carcinoma

This is a rare form of cancer. Nearly everyone who gets it is 50 or older. It’s aggressive and often spreads to other parts of the body. 

Kaposi sarcoma

Kaposi sarcoma appears on your skin but also as tumors in the cells that line your mouth, lymph nodes, lungs, or digestive tract. Typically skin lesions happen on the legs or face. 

Actinic keratosis

Actinic keratosis is an area of red or brown, scaly, rough skin, which can develop into squamous cell carcinoma. 

Moles and skin cancer 

The majority of malignant or cancerous melanomas are brown-to-black pigmented lesions, or moles. 

Moles are simply growths on the skin that rarely develop into cancer. Most people have 10 to 30 moles on their body that can be identified as flat or raised, smooth on the surface, round or oval in shape, pink, tan, brown, or skin-colored, and no larger than a quarter-inch across. 

If a mole on your body looks different from the others, ask your health care provider to take a look at it. A nevus is a mole, and abnormal moles are called dysplastic nevi. These can potentially develop into melanoma over time.

Dysplastic nevi are not cancer, but they can become cancer. People sometimes have as many as 100 or more dysplastic nevi, which are usually irregular in shape, with notched or fading borders. Some may be flat or raised, and the surface may be smooth or rough ("pebbly"). They are often large, at a quarter-inch across or larger, and are typically of mixed color, including pink, red, tan, and brown.

Lymphoma of the skin

When lymphoma (cancer of the white blood cells, or lymphocytes) starts in your skin (not in other organs or tissues) it is called a skin lymphoma. Lymphoma that starts in the lymph nodes and spreads to the skin isn’t lymphoma of the skin. 

Skin cancer symptoms depend on the type of skin cancer you have. You can get skin cancer anywhere you have skin, but it’s most common on areas that see the most sun: scalp, face, lips, ears, neck, chest, arms and hands, and legs.

People with darker skin tones are more likely to have skin cancer in areas that aren’t in the sun as often, like the palms of the hands, the soles of the feet, the groin, the inside of the mouth, and under their nails. 

Basal cell carcinoma symptoms

A basal cell carcinoma (BCC) usually looks like a raised, smooth, pearly bump on the sun-exposed skin of the head, neck, or shoulders. Others signs include:

  • Small blood vessels may be visible within the tumor.
  • A central depression with crusting and bleeding (ulceration) frequently develops.
  • A BCC often appears as a sore that does not heal.

Squamous cell carcinoma symptoms 

A squamous cell carcinoma (SCC) is commonly a well-defined, red, scaling, thickened bump on sun-exposed skin. It may turn into an ulcer and bleed. If you don’t treat it, it may develop into a large mass.

Melanoma symptoms

Signs of a cancerous melanoma include:

  • A change in size, shape, color, or elevation of a mole
  • The appearance of a new mole during adulthood, or new pain, itching, ulceration, or bleeding of an existing mole

Merkel cell carcinoma

Merkel cell carcinoma usually looks like firm, shiny nodules on or just under your skin and in hair follicles. You’ll see these nodules most often on your head, neck, and trunk. 

Different types of skin cancer can show up as a range of symptoms, as described above. Be on the lookout for raised or scaly bumps, sores that bleed or don't heal, or moles that change size, shape or color, especially in areas of your body that get a lot of sun.

The following easy-to-remember guideline, "ABCDE," is useful for checking moles to see if they fit the signs for malignant melanoma:

  • Asymmetry. One side of the mole does not look like the other.
  • Border irregularity. The border of your mole may be notched or irregular.
  • Color. Melanomas are often a mixture of black, tan, brown, blue, red, or white.
  • Diameter. Cancerous moles can be larger than 6 millimeters across (about the size of a pencil eraser), although with early detection they will not reach this size.
  • Evolution. Has the mole changed over time?

If you have dark skin, look for a dark spot, growth, or darker patch of skin that is growing, bleeding, or changing in any way. Pay attention to any sores that don’t heal, or heal and return. Melanoma can also show up as a patch of skin that feels rough and dry. 

Ultraviolet (UV) light exposure, most commonly from sunlight, is overwhelmingly the most frequent cause of skin cancer.

Other important causes of skin cancer include the following:

  • Use of tanning booths
  • Immunosuppression, or impairment of the immune system
  • Exposure to unusually high levels of radiation, such as from X-rays
  • Contact with certain chemicals, such as arsenic (miners, sheep shearers, and farmers) and hydrocarbons in tar, oils, and soot (which may cause squamous cell carcinoma)

Skin cancer risk factors

The following people are at the greatest risk of skin cancer:

  • People with fair skin, especially types that freckle, sunburn easily, or become painful in the sun
  • People with light (blond or red) hair and blue or green eyes
  • Those with certain genetic disorders that deplete skin pigment, such as albinism and xeroderma pigmentosum (a disease in which DNA repair mechanisms, especially in response to ultraviolet light, is impaired)
  • People who have already been treated for skin cancer
  • People with numerous moles, unusual moles, or large moles that were present at birth
  • People with close family members who have developed skin cancer
  • People who had at least one severe sunburn early in life
  • People with burns unrelated to sunburn
  • People with indoor occupations and outdoor recreational habits

Basal cell carcinomas and squamous cell carcinomas are more common in older people. Melanomas are one of the most common cancers in younger people, especially in people ages 25 to 29. The risk of melanoma rises with age.

Skin cancer is more common in people assigned female before birth who are younger than 50. After age 50, the statistic switches: people assigned male at birth are more likely to have it. 

People with darker skin tones often get a later diagnosis for their skin cancer, which makes it more difficult to treat and often affects the outcome for this population. 

Many people, especially those who have fair coloring or have had extensive sun exposure, periodically check their entire body for suspicious moles and lesions.

Have your primary doctor or a dermatologist check any moles or spots that concern you.

See your doctor to check your skin if you notice any changes in the size, shape, color, or texture of pigmented areas (such as darker or a change in areas of skin or moles).

If you have skin cancer, your skin specialist (dermatologist) or cancer specialist (oncologist) will talk to you about symptoms of metastatic disease that might require care in a hospital.

If you think a mole or other skin lesion has turned into skin cancer, your doctor will probably refer you to a dermatologist. The dermatologist will examine any moles in question and, in many cases, the entire skin surface Tests for skin cancer may include:

  • The doctor may use a handheld device called a dermatoscope to scan the lesion. 
  • A sample of skin (biopsy) will be taken so that the suspicious area of skin can be examined under a microscope.
  • A biopsy is done in the dermatologist's office.

Skin cancer diagnosis

After a physical exam and tests, if a biopsy shows that you have malignant cancer, you may get more testing to find out whether it has spread. This may involve blood tests, a chest X-ray, and other tests as needed. This is only needed if the melanoma is of a certain size.

 

The stage your doctor assigns your cancer tells you how much cancer is in your body. The stages range from 0–IV, and typically the higher the number, the more the cancer has spread. Cancer in higher stages is usually harder to treat. 

Melanoma stages

Stage 0 (melanoma in situ) means the melanoma is only in the top layer of your skin.

Stage I means the melanoma is low risk and hasn’t spread. Usually surgery can cure it.

Stage II means it hasn’t spread, but it has features that mean it may come back (recur).  

Stage III means it has spread to nearby lymph nodes or nearby skin.

Stage IV means the cancer has spread to distant lymph nodes, skin, or internal organs. 

Non-melanoma stages

Stage 0 means the cancer is only in the top layer of your skin.

Stage I means the cancer is in the top and middle layers of your skin.

Stage II means the cancer is in the top and middle layers of your skin and moves to target your nerves or deeper layers of skin.

Stage III means the cancer has spread beyond your skin to your lymph nodes.

Stage IV means the cancer has spread to other parts of your body and your organs like your liver, lungs or brain.

Skin cancer treatment for basal cell carcinoma and squamous cell carcinoma is straightforward. Usually, surgical removal of the lesion is enough. Malignant melanoma, however, may need several treatment methods -- depending on the size of the tumor -- including surgery, radiation therapy, immunotherapy, and chemotherapy. 

Radiation therapy

Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or keep them from growing. A machine targets the area where the cancer is and sends radiation to it. Doctors often use this treatment for BCC and SCC.  

Chemotherapy

Chemotherapy stops the growth of cancer cells either by killing the cells or stopping them from dividing. When you have BCC, SCC, or actinic keratosis, you usually take chemotherapy as a topical cream or lotion. 

Photodynamic therapy

With this treatment, your doctor uses a combination of a drug and a special light to kill cancer cells. The drug doesn’t work until it’s exposed to the light.

Targeted drug therapy

These medications can find and attack specific cells (cancer cells) based on certain substances on the cells such as proteins or gene mutations. These drugs can stop cancer cells from dividing and are more precise than chemotherapy, which destroys any fast-growing cell. 

Immunotherapy

This treatment uses your immune system to help attack cancer cells. The drugs can boost your immune system or direct it toward the cancer.

Dermabrasion

This procedure uses a rotating wheel or small particles to rub away the top layer of your skin cells to remove cancerous cells. 

Because of the complexity of treatment decisions, people with malignant melanoma may benefit from the combined expertise of the dermatologist, a cancer surgeon, and an oncologist.

Small skin cancer lesions may be removed through a variety of techniques. Your doctor may be able to simply cut it away (simple excision) or freeze it off with liquid nitrogen (cryosurgery), or you may need other procedures.

Mohs surgery 

Larger tumors, lesions in high-risk locations, recurrent tumors, and lesions in cosmetically sensitive areas are removed by a technique called Mohs micrographic surgery. For this technique, the surgeon carefully removes tissue, layer by layer, until they reach cancer-free tissue.

Curettage and electrodesiccation

This is a procedure where a doctor scrapes the tumor and then burns the tissue with an electric needle.

Malignant melanoma is treated more aggressively than just surgical removal. To ensure the complete removal of this dangerous malignancy, 1-2 centimeters of normal-appearing skin surrounding the tumor is also removed. Depending on the thickness of the melanoma, neighboring lymph nodes may also be removed and tested for cancer. The sentinel lymph node biopsy method uses a mildly radioactive substance to identify which lymph nodes are most likely to be affected.

 

The side effects from your skin cancer treatment will depend on the type of treatment you receive. But there are some common issues, such as:

  • Fatigue
  • Pain from surgery or other treatments
  • Chemotherapy side effects such as low blood counts, nausea, and vomiting
  • Skin rash from immunotherapy
  • Headache or high blood pressure from targeted therapy
  • Problems sleeping  
  • Blistering and peeling from radiation
  • Changes in skin color
  • Hair loss in the area you're treating
  • Swelling, scars, or bleeding

Some of the possible complications of skin cancer include:

  • The cancer coming back (recurrence). Some types of cancer, such as basal cell carcinomas, commonly come back, even after treatment.

  • Increased risk of other types of skin cancer. You may get other skin cancers once you’ve had it. 

  • Spread of cancer. Sometimes skin cancer spreads (metastasizes) to nearby lymph nodes and other areas of the body. 

Most skin cancer is cured surgically in the dermatologist's office. Of skin cancers that do recur, most do so within 3 years. Be sure to follow up with your dermatologist as recommended. Make an appointment immediately if you suspect a problem.

If you have advanced malignant melanoma, your oncologist may want to see you every few months. These visits may include total body skin exams, regional lymph node checks, and periodic chest X-rays and body scans. Over time, the intervals between follow-up appointments will increase. Eventually these checks may be done only once a year.

You can reduce your risk of getting skin cancer by following these guidelines:

  • Limit sun exposure. Avoid the sun's intense rays between 10 a.m. and 4 p.m.
  • Apply sunscreen every day. Use a sunscreen with sun protection factor (SPF) of at least 30 both before and every 60 to 80 minutes during outdoor exposure. Select products that filter both UVA and UVB light. The label will tell you.
  • If you are likely to sunburn, wear a long-sleeved shirt, pants, and a wide-brimmed hat.
  • Avoid tanning booths.
  • Conduct monthly self-exams.

Skin self-exams

Monthly skin self-exams improve your chances of finding a skin cancer early, when it has done a minimum of damage to your skin and can be treated easily. Regular self-exams help you recognize any new or changing features.

  • The best time to do a self-exam is right after a shower or bath.
  • Do the self-exam in a bright room; use a full-length mirror and a hand-held mirror.
  • Learn where your moles, birthmarks, and blemishes are and what they look like.
  • Each time you do a self-exam, check these areas for changes in size, texture, and color, and for ulceration. If you notice any changes, call your doctor or dermatologist.

Check all areas of your body, including hard-to-see areas. Ask a loved one to help you check if there are areas you can't see.

  • Look in the full-length mirror at your front and your back (use the handheld mirror to do this). Raise your arms and look at your left and right sides.
  • Bend your elbows and look carefully at your palms, nails, forearms (front and back), and upper arms.
  • Examine the backs and fronts of your legs. Look at your buttocks (including the area between the buttocks) and your genitals (use the handheld mirror to make sure you see all skin areas).
  • Sit down and examine your feet carefully, including the nails, soles, and between the toes.
  • Look at your scalp, face, and neck. You may use a comb or blow dryer to move your hair while examining your scalp. You may also enlist the help of a friend or family member.

If you are at high risk for developing skin cancer, ask you doctor about oral nicotinamide, a vitamin B3 supplement taken twice daily in pill form that can decrease the rate of new squamous cells and basal cells by almost 25%.

Although the number of skin cancers in the U.S. continues to rise, more skin cancers are being caught earlier, when they are easier to treat. Illness and death rates have gone down.

When treated properly, the cure rate for both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) approaches 95%. The remaining cancers recur at some point after treatment.

  • Recurrences of these cancers are almost always local (not spread elsewhere in the body), but they often cause significant tissue destruction.
  • Two percent of squamous cell carcinomas will eventually spread elsewhere in the body and turn into dangerous cancer. Metastatic squamous cell carcinoma of the skin is usually seen in people with compromised immune systems.

In most cases, the outcome of malignant melanoma depends on the thickness of the tumor at the time of treatment.

  • Thin lesions are almost always cured by simple surgery alone.
  • Thicker tumors, which usually have been present for some time but have gone undetected, may spread to other organs. Surgery removes the tumor and any local spread, but it cannot remove distant metastasis. Other therapies, such as radiation therapy, immunotherapy, or chemotherapy, are used to treat the metastatic tumors.
  • Malignant melanoma causes more than 75% of deaths from skin cancer.

Living with skin cancer presents many new challenges for you and your family and friends. You will probably have many worries about how the cancer will affect you and your ability to "live a normal life," to care for your family and home, to hold your job, and to continue the friendships and activities you enjoy.

Many people with a skin cancer diagnosis feel a range of emotions. For most people with skin cancer, talking about their feelings and concerns helps. Your friends and family members can be very supportive. They may be hesitant to offer support until they see how you are coping. Don't wait for them to bring it up. If you want to talk about your concerns, let them know.

Some people don't want to burden their loved ones or prefer talking about their concerns with a more neutral professional. A social worker, counselor, or member of the clergy can be helpful. Your dermatologist or oncologist should be able to recommend someone.

Many people with cancer are profoundly helped by talking to other people who have cancer. Sharing your concerns with others who have been through the same thing can be remarkably reassuring. Support groups for people with cancer may be available through the medical center where you are receiving your treatment. The American Cancer Society also has information about support groups throughout the U.S.

Skin cancer is very common but also very treatable with medication and procedures if you catch it early. Know the symptoms of skin cancer, and get regular check-ups with your dermatologist. Help prevent skin cancer by protecting your skin in the sun and by noting any suspicious-looking spots or moles. 

What is the survival rate for skin cancer?

Treatment can cure most skin cancers, especially if you find and treat them early and they don’t have a chance to spread to other parts of the body. For example, the 5-year survival rate for melanoma is 99%. This means at the 5-year mark, 99% of people with melanoma are still alive. 

If your melanoma has spread to nearby lymph nodes, your survival rate drops to 68%, and if it spreads to distant lymph nodes or other organs, it’s 30%. Nonmelanoma cancer survival rates are high, between 95%-100%, because they are low grade and slow-growing. 

Can you live a full life with skin cancer? 

Your quality of life will depend on a few things, such as the type, location, and stage of your cancer, your overall health, and how well your cancer responds to treatment. If your cancer responds well to treatment, you are very likely to live a normal life and may even be completely cured of your cancer. 

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