Skin Cancer

Skin cancer is a condition that manifests in the skin tissue, often resulting from overexposure to sunlight or UV rays.

Early symptoms include discolored and uneven spots on the skin, changes in appearance of skin and burning sensations.

There are many options for diagnosing skin cancer, and its progress or stage determines treatment options.

Skin cancer is the most common type of cancer in the United States but often doesn’t cause severe symptoms in early stages, which makes regular screenings (if you’re eligible) vitally important. Screening also increases the likelihood of catching skin cancer in its earlier, easier treated stages.

Skin cancer definition, symptoms and complications

What is skin cancer?

The skin is the body’s largest organ and has many functions: protection against heat, sunlight, injury, and infection; control of body temperature; and vitamin D production.

The two main layers of the skin are the epidermis (visible upper or outer layer) and the dermis (deeper or inner layer).

Cancer beginning in the skin occurs when abnormal cells begin to grow out of control in the skin, often first detected as an unusual looking spot or mole. The abnormal cells beginning in the skin can spread to tissues and other organs as the cancer progresses.

Are there different types of skin cancer?

There are different types of skin cancer.

The majority of skin cancers begin in the epidermis, which is made up of three kinds of cells: squamous cells, basal cells and melanocytes, the cells that make pigment and cause the skin to darken with ultraviolet light exposure.

The most common skin cancers include:

• Squamous cell skin cancer: These cancers also appear on sun-exposed areas of the body such as the face, ears, neck, lips and backs of the hands. They can also develop in scars or chronic skin sores and can sometimes start within actinic keratosis, a pre-cancerous skin condition caused by too much exposure to the sun.
• Basal cell skin cancer: This is not only the most common type of skin cancer, but the most common type of cancer in humans. About 8 out of 10 skin cancers are basal cell carcinomas. They are usually found in skin exposed to sunlight. They rarely spread, but if left untreated, they can become locally destructive.
• Melanoma: Although less common than squamous cell or basal cell cancers, they are also more serious and more likely to spread if not diagnosed and treated early. Melanomas develop from melanocytes, the pigment-making cells of the skin. Melanocytes can also form non-cancerous moles. Melanoma can also affect the eye and eyelid.
• Merkel cell: Merkel cell carcinoma (MCC) is an uncommon type of skin cancer that can grow quickly and can be hard to treat if it spreads beyond the skin. Merkel cells are very close to nerve endings in the skin and are thought to be a type of neuroendocrine cell because they share some features with nerve cells and hormone-making cells.
• Karposi sarcoma: This cancer develops from the cells that line lymph or blood vessels. Karposi sarcoma is caused by human herpes virus 8. It usually appears as tumors on the skin or on mucosal surfaces, such as inside the mouth, but tumors can also develop in other parts of the body. The most common type in the U.S. is AIDS-related Karposi syndrome. These cancers are treated as part of the HIV/AIDS management.
• Mycosis Fungoides and the Sézary Syndrome (cutaneous lymphoma): This is a type of non-Hodgkin’s lymphoma in which malignant immune T-cells migrate to the skin causing lesions. Cutaneous lymphoma is often managed topically.

What are the symptoms of skin cancer?

Symptoms differ between patients, but those experiencing early stages of skin cancer may experience the following:

• A new spot on the skin or a spot that is changing in size, shape, or color
• A spot that looks different from all of the other spots on the skin
• Spread of pigment from the border of a spot into surrounding skin
• Redness or a new swelling beyond the border of the mole
• Change in the surface of a mole – scaliness, oozing, bleeding, or the appearance of a lump or bump
• A sore that doesn’t heal
• Change in sensation, such as itchiness, tenderness, or pain

Like other cancers, skin cancer progresses in stages, during which symptoms may change or become more severe. The following stages are used to track the progress of skin cancer:

• Stage 0: The malignant tumor is confined to the upper layer of the skin. Cancer cells are only in the outer layer (epidermis) and have not grown to the deeper layers (dermis).
• Stage I: There are cancer cells in both epidermis and dermis. A Stage I melanoma is up to 2mm thick (Breslow thickness). It may or may not have ulceration.
• Stage II: Stage II is defined by tumor thickness and ulceration. Cancer cells exist in both the epidermis and dermis, but there is no evidence the cancer has spread to the lymph nodes or distant sites (metastasis).
• Stage III: Defined by the level of lymph node involvement and ulceration, Stage III melanoma has spread to one or more regional lymph nodes or has developed a deposit of melanoma in the skin or dermis along the lymphatics prior to reaching a lymph node. This is called an in transit or satellite metastasis.
• Stage IV: The cancer has spread beyond the original tumor site and regional lymph nodes to more distant areas of the body, known as metastasis. The most common sites of metastasis are distant skin and lymph nodes, then lungs, liver, brain, bone and the intestines.

Are there complications to skin cancer?

Common complications resulting from skin cancer include changes to the skin, including changing color, texture, scarring and lymphedema. Metastasis, or the spread of cancer to other organs or tissues, can also occur as a result of progressive skin cancer.

Skin cancer causes, risk factors and prevention

What causes or contributes to the development of skin cancer?

While there are no singular causes for any type of cancer, skin cancer is most often the result of overexposure to sun and UV radiation. This may occur due to high levels of regional UV, lack of sun protective clothing or failure to use sunscreen during periods of prolonged sun exposure, especially when this causes sunburn or blistering.

Are there risk factors for developing skin cancer?

Anything that increases the risk of getting a disease is called a risk factor. Having a risk factor does not mean that someone will get a particular cancer; not having risk factors doesn’t mean that someone will not get a particular cancer.

Risk factors for skin cancer include:

• High UV radiation environments
• Frequent sunburns and blistering
• Lack of sun protective clothing or sunscreen
• Contact with certain chemicals, such as tar and coal
• Tan or use tanning beds.
• Light-colored eyes, blond or red hair and fair or freckled skin
• Many moles
• Actinic keratosis
• A family history of skin cancer
• Being an organ transplant recipient
• Taking medications that suppress or weaken your immune system
• Exposure to ultraviolet light therapy for treating skin conditions such as eczema or psoriasis

Can skin cancer be prevented? How?

In many cases, skin cancer can be prevented by protecting your body from the sun.

Ways to protect your body from the sun include:

• Using sunscreen
• Limiting direct exposure to high UV sunlight (usually midday sun)
• Wearing skin-protective clothing

These preventive measures can reduce the potential to develop skin cancer.

Predisposition to skin cancer – related to previous medical treatments or genetics – cannot be mediated, but taking extra precautions will still lower the risk of skin cancer.

Skin cancer diagnosis and treatment

How is skin cancer diagnosed?

The following screenings, tests and procedures may be used to detect or diagnose skin cancer and determine the stage of its progress:

• The ABCDE visual test: This is a visual test you can conduct at home to identify potential skin cancer that is then confirmed by a doctor. This method is especially effective for detecting possible melanoma. Each letter of the test indicates a different aspect of the potential cancer, usually a freckle or mole on the skin:
  • A = Asymmetry. Melanomas are frequently asymmetrical, meaning the shape of one half does not match the other.
  • B = Border. Melanomas often have uneven or irregular borders with ragged or notched edges.
  • C = Color. Melanomas can contain multiple shades of brown or black or mixed with white, gray, blue or red. Some melanomas will appear as a loss of color in an existing mole or in the area surrounding the mole.
  • D = Diameter. Melanomas are often larger than 6 mm (1/4 inch) in diameter. However, with increased awareness about early detection, about 30% of melanomas are found when they are less than 6 mm in diameter.
  • E = Evolution. Any change in a spot indicates potential skin cancer. Melanomas typically have shown some evidence of change in the months prior to diagnosis.
• Biopsy: Skin cancer diagnosis requires a skin biopsy. Once a spot that might be skin cancer has been identified, a physician examines the spot. If they believe it looks like a potential site for skin cancer, they will remove part or all of the spot in a procedure called a skin biopsy. A biopsy the only way to know whether you have skin cancer. The doctor examines the removed skin under a microscope to look for cancer cells. If cancer cells are found, the biopsy report will tell you what type of skin cancer cells were found.

Read more: What to know about cancer screening guidelines in 2026>>

What options are available for skin cancer treatment? Are any more common or successful?

There are multiple factors of skin cancer that require medical attention, and several methods of treatment may be necessary to address all patient symptoms.

There are different types of treatment for patients with non-melanoma skin cancer, depending on the stage of the cancer and the person’s overall health. Treatment also depends on cancer stage.

Treatment methods for basal squamous cell carcinoma include:

Surgery

Electrodesiccation and curettage: The tumor is cut from the skin with a curette (a sharp, spoon-shaped tool). A needle-shaped electrode is then used to treat the area with an electric current that stops the bleeding and destroys skin cancer cells that remain around the edge of the wound.

Simple excision: The tumor is cut from the skin along with some of the normal skin around it.

Mohs micrographic surgery: Used mostly for tumors on the face, Mohs surgery involves cutting the tumor from the skin in thin layers. During surgery, the edges of the tumor and each layer of tumor removed are viewed through a microscope to check for cancer cells. Layers continue to be removed until no more cancer cells are seen. This type of surgery removes as little normal tissue as possible.

Radiation therapy

Radiation therapy also is a common skin cancer treatment option for non-melanoma skin cancer, especially for tumors that are large or are located on areas of the body that are difficult to treat. It also may be the best option for patients who have other medical complications in addition to their skin cancer. With this procedure, high-energy particles are delivered to the affected area over several treatment sessions to destroy the cancerous tissue.

Topical chemotherapy

Topical chemotherapy for non-melanoma skin cancer and actinic keratosis is usually applied to the skin in a cream or lotion. The way the chemotherapy is given depends on the condition being treated. Retinoids (drugs related to vitamin A) are sometimes used to treat squamous cell carcinoma of the skin.

Photodynamic therapy

This cancer treatment uses a drug and a certain type of laser light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein. The drug collects more in cancer cells than in normal cells. For skin cancer, laser light is shined onto the skin and the drug becomes active and kills the cancer cells. Photodynamic therapy causes little damage to healthy tissue.

Immunotherapy

Also called biologic therapy, these drugs use the patients’ immune systems to fight the cancer. Topical imiquimod therapy (a cream applied to the skin) may be used to treat some small basal cell carcinomas.

Treatment methods for melanoma and Merkel cell cancer treatment include:

Surgery

Wide local excision: Surgery to remove the tumor is the primary treatment of all stages of melanoma. A wide local excision is used to remove the melanoma and some of the normal tissue around it. The size of the excision is dependent on the thickness of the tumor.

Lymph node sampling, including sentinel biopsy: To test for cancer in lymph nodes, any enlarged lymph nodes that can be felt will be biopsied directly. Otherwise, you may have a sentinel node biopsy, which checks for cancer in the first lymph node the cancer is likely to spread to from the tumor. A radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the dye is removed. A pathologist views the tissue under a microscope to look for cancer cells.

Lymphadenectomy: If cancer cells are found, more lymph nodes will be removed and tissue samples checked for signs of cancer. Even if the doctor removes all the melanoma that can be seen at the time of surgery, some patients may be offered systemic therapy or clinical trial enrollment after surgery to kill any cancer cells that may remain.

Regional chemotherapy

Isolated limb perfusion (ILI): This is a method of drug delivery that is designed to deliver high local doses of chemotherapy for melanomas in the extremities, while avoiding systemic toxicity. ILI involves the following steps: Placement of catheters into a major vein and artery nearest to the tumor, placing a tourniquet around the limb to keep the chemotherapy confined and infusing the drug through the catheters into the affected extremity. Perfusion lasts for approximately 60 minutes and may be done with one or a combination of drugs while the limb is heated to increase the effectiveness of the drugs. Patients are hospitalized until limb inflammation subsides.

Biologic therapy: These drugs use the patients’ immune systems to fight the cancer. The following types of biologic therapy are being used or studied in the treatment of melanoma: checkpoint inhibitor monoclonal antibodies, checkpoint blockade drugs, interferon and interleukin-2 (IL-2).

Targeted therapy

This type of treatment uses drugs or other substances to attack cancer cells, usually causing less harm to normal cells than chemotherapy or radiation therapy. The following types of targeted therapy are used or are being studied in the treatment of melanoma:

Signal transduction inhibitor therapy blocks signals that are passed from one molecule to another inside a cell to kill cancer cells. Several different types are used to treat some patients with advanced melanoma or tumors that cannot be removed by surgery. If your melanoma has a certain mutation, you may receive a BRAF or MEK inhibitor therapy.

Oncolytic virus therapy is a type of targeted therapy that is being studied in the treatment of melanoma that uses a virus that infects and breaks down cancer cells but not normal cells. Radiation therapy or chemotherapy may be given after oncolytic virus therapy to kill more cancer cells.

Angiogenesis inhibitors are a type of investigational targeted therapy that blocks the growth of new blood vessels. In cancer treatment, they may be given to prevent the growth of new blood vessels that tumors need to grow.

Standard treatments for Merkel cell skin cancer

For Merkel cell, surgical excision, sometimes sentinel lymph node biopsy for certain size tumors and radiation therapy. Other types of treatments are being studied in clinical trials.

Standard treatments for eye cancer

In adults, choroidal melanoma is the most common primary intraocular cancer. It starts in the choroid, a heavily pigmented, blood vessel-rich layer underneath the retina. There are approximately 1,500 new cases of choroidal melanoma diagnosed in the U.S. each year. Melanoma can also arise in the conjunctiva or the eyelid. Very rarely, lymphoma begins inside the eyes. Primary intraocular lymphomas are almost always a type of non-Hodgkin lymphoma.

Although rare, squamous cell cancer is the most common cancer of the conjunctiva, the covering of the eyeball and inside of the eyelid. This type of cancer usually grows on the surface of the conjunctiva but can grow into and around the eye. It is generally slow growing (low grade), and very rarely spreads to another part of the body.

Detailed explanations of these procedures can be found here.

What is the prognosis for skin cancer? Is there a cure?

The prognosis and treatment options depend on the following:

The stage of the cancer (whether it affects part of the skin, involves the whole skin, or has spread to other places in the body).

Whether the tumor can be completely removed by surgery.

The patient’s general health.

According to the American Cancer Society, the five-year survival rates for those with localized skin cancer (cancer that has not spread to other areas) is 99%. This rate is lower for regional and distant cancers, at 68% and 30% respectively.

Who treats skin cancer?

Our surgeons are part of a multidisciplinary team of specialists at Siteman Cancer Center and WashU Medicine who provide the highest level of care for people with skin cancer.

Some skin cancer cases require treatment from several medical and surgical specialists, including dermatologists, dermatologic surgeons, medical and surgical oncologists, radiologists, radiation oncologists, ophthalmologists, otolaryngologists and plastic surgeons.

At WashU Medicine, our patients have access to all specialists needed for their care.