Skin cancer occurs when errors (mutations) in the cells of the skin develop. These errors cause the cells to grow out of control and form a tumor.
People who have a lot of sun exposure and/or a family history of skin cancer are at greater risk for developing this type of cancer. Also, some genes can increase your risk for this disease.
Skin cancer is most often caused by excessive sun exposure, especially when unprotected. This type of cancer can affect all skin colors and types, but it is more common in people with fair skin who burn easily or freckle or have a lot of moles on their bodies. It is also more likely to develop in areas that are not exposed to sunlight, like the palms of the hands and feet or the genital area.
The most common forms of skin cancer are basal cell carcinoma and squamous cell carcinoma, which can appear as firm, red nodules that bleed or have a crusty appearance, or as scaly growths that won’t heal or sores that bleed or form a crust. It can occur on areas that are most commonly exposed to the sun, like the nose, forehead, ears, face, lips, arms and legs; but it can also grow in other parts of the body, including the scalp, neck, groin or genitals.
Some people have an inherited disease, called xeroderma pigmentosum (XP), which makes them more sensitive to UV rays and increases their risk of developing skin cancer. Certain medications, such as some steroids, can also increase your risk of developing squamous cell carcinoma. This includes drugs that suppress your immune system, such as interferon alfa (INFARCEPT) and cyclosporine, or that increase your sensitivity to sunlight, such as the BRAF inhibitors dabrafenib (Tafinlar), encorafenib (Braftovi), and vemurafenib (Zelboraf).
Melanoma is less common than these other types of skin cancer, but it is more dangerous. It grows in the cells (melanocytes) that give your skin, eyes and hair color. This type of skin cancer can spread quickly, so it’s important to check your entire body regularly for abnormal moles and other changes.
It’s important to be familiar with the look of your skin so you can pick out any unusual spots or moles. If any of your moles change shape, color or thickness over time, see a doctor right away.
Some types of skin cancer don’t show up as a new mole. Instead, they often look like a raised, scaly patch or sore that bleeds or crusts. These are called nonmelanoma skin cancers, and they most often develop on areas that get sun exposure. These include the face, ears and hands, but also other parts of the body such as the arms, legs and back. People with fair skin, or a history of sunburn or hereditary diseases such as xeroderma pigmentosum and Muir-Torre syndrome are more likely to develop these kinds of nonmelanoma skin cancers.
Basal cell carcinoma usually appears as a dome-shaped lump that has a pearly color and sometimes bleeds. Squamous cell carcinoma tends to appear as a red, crusty or scaly patch, sore or wound that won’t heal. These cancers grow quickly and can spread to other parts of the body, especially if they aren’t treated early.
Melanoma is less common, but it is more dangerous than the other two types. It grows in the cells that produce melanin, the dark pigment that gives your skin its color. It can also grow in normal skin or in an existing mole. This type of skin cancer can spread to other parts of the body and cause serious health problems, including death.
GPs can examine a suspicious area of skin and refer you to a specialist (dermatologist) if they suspect it’s cancer. They’ll look at the size, shape, colour and texture of the spot or mole. They’ll also check for bleeding, scaling or any other changes in the area. If the doctor thinks it’s a skin cancer, they’ll take a sample of it and send it to a laboratory for testing. This is called a biopsy. A biopsy is usually safe and quick, but it’s a little invasive as the doctor may need to cut away some of the skin or growth to send for testing.
A blood test to check your lymph nodes is usually done as well, but it’s not always needed. There are several different types of skin biopsies, including a shave biopsy, in which the doctor uses a sterile blade to shave off the abnormal growth. They may also do a punch biopsy, in which they use a special tool to cut out a circular piece of tissue that includes the deep layers underneath. All biopsy samples are sent to a lab to be looked at under a microscope by a specialist doctor (pathologist).
People with a history of skin cancer, particularly basal cell carcinoma and squamous cell carcinoma, have an increased risk of developing more skin cancer. This is especially true if the cancers are more serious or have spread to other parts of the body.
Nonmelanoma skin cancers like basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are very common, but they’re almost always cured when found and treated early. Melanoma is the deadliest form of skin cancer. It starts in the cells (melanocytes) that give color to the skin, eyes and hair. People who have a light complexion, blue or green eyes and blond or red hair are at increased risk of developing melanoma. They should have a regular checkup with their doctor and watch for any new moles or unusual growths.
Non-melanoma skin cancers grow in the squamous cells that make up most of the outer layer of the skin. They usually develop on areas that get the most sun, such as the head, neck, arms, hands and legs. These types of skin cancers may look like a flesh-colored bump, pearl-like bump or patch. They can also appear as a sore that doesn’t heal or a scaly patch that bleeds.
A squamous cell carcinoma typically starts in the upper layers of the skin and can grow into deeper tissues, such as nerves and bones. It can also spread to other parts of the body, such as the lymph nodes and lungs. Kaposi sarcoma (KS) often occurs in the legs, feet or face, but it can also appear in the genitals, mouth or lymph nodes.