Skin cancer answers, in plain language.

Skin cancer is the uncontrolled growth of abnormal skin cells. Ultraviolet (UV) light from the sun or tanning beds damages the DNA in those cells, and that damage causes most cases.

The 3 most common types are basal cell carcinoma, squamous cell carcinoma, and melanoma. Skin cancer is the most common cancer in the United States. About 1 in 5 Americans will develop it in their lifetime.

Melanoma causes the most deaths. It is far less common than basal cell or squamous cell cancer, but it is much more likely to spread when it isn't caught early. The American Cancer Society estimates about 112,000 new invasive melanomas and about 8,510 melanoma deaths in the United States in 2026.

Merkel cell carcinoma is rarer than melanoma and also aggressive.

UV light is the main cause. Risk goes up with a history of sunburns, tanning bed use, fair skin that burns easily, light hair or eyes, many moles or atypical moles, a family or personal history of skin cancer, older age, and a weakened immune system, for example after an organ transplant.

Anyone can get skin cancer, including people with dark skin.

Most skin cancers are cured when they're found early, usually with a minor procedure. Timing matters most for melanoma. The 5-year survival rate is 99% when melanoma is found before it reaches the lymph nodes. It falls to 76% once it has reached nearby lymph nodes and 35% after it has spread to distant organs.

Those numbers describe large groups. They can't predict what will happen for one person, and newer treatments keep improving results.

It depends on the type. Basal cell carcinoma almost never spreads, though it can grow deep and damage nearby tissue. Squamous cell carcinoma spreads in a small share of cases, more often from the lip or ear or in people with weakened immune systems. Melanoma and Merkel cell carcinoma are the most likely to spread, first to nearby lymph nodes and then to distant organs.

Yes. The risk is lower, but it isn't zero. The American Cancer Society puts the lifetime risk of melanoma at about 1 in 33 for White people, 1 in 200 for Hispanic people, and 1 in 1,000 for Black people.

In people with darker skin, skin cancer is often found at a later stage, and outcomes are worse as a result. Melanoma in darker skin often appears where the sun rarely reaches: the palms, the soles, under the nails, and inside the mouth. Check those areas.

Melanoma is a cancer of melanocytes, the cells that make the pigment melanin. Most melanomas show up as a new spot on the skin. Some grow within a mole that has been there for years.

Melanoma can also appear without much pigment, as a pink or skin-colored bump. Doctors call that amelanotic melanoma, and it is easy to miss.

A is for asymmetry: one half doesn't match the other. B is for border: irregular, scalloped, or poorly defined. C is for color: different shades of tan, brown, or black, sometimes with white, red, or blue. D is for diameter: melanomas are usually larger than 6 millimeters, about the size of a pencil eraser, when diagnosed, though they can be smaller. E is for evolving: a spot that looks different from your others or is changing in size, shape, or color.

A spot that fits any of these deserves a look from a dermatologist. So does a spot that simply stands out from all your other moles.

No. Melanoma can develop on the palms, the soles, under a fingernail or toenail, on the scalp, inside the mouth, on the genitals, and in the eye. These locations are easy to overlook. A self-exam should include them.

Many dark nail lines are harmless, especially when several nails have them. A single new band deserves a prompt exam by a dermatologist. That is even more true if the band is widening, if it has blurry or uneven borders, or if pigment is spreading onto the skin around the nail.

We can't tell you what your nail line is. Only an exam, and sometimes a biopsy, can do that.

Breslow depth is the thickness of a melanoma in millimeters. A pathologist measures it under the microscope, from the top layer of the skin down to the deepest melanoma cell.

For melanoma that hasn't spread, thickness is one of the strongest predictors of outcome. It guides how wide the surgery should be and whether the surgeon should check a lymph node.

Stage 0, also called melanoma in situ, is confined to the top layer of the skin. Stages I and II are melanomas that have grown deeper but remain in the skin; the stage depends on thickness and on whether the surface is broken down (ulceration). Stage III means melanoma has reached nearby lymph nodes or nearby skin. Stage IV means it has spread to distant organs.

The sentinel node is the first lymph node that drains the area of skin where the melanoma grew. A surgeon finds it with a tracer injected near the melanoma site, removes it, and a pathologist checks it for melanoma cells.

Doctors often discuss this procedure when a melanoma is thicker than about 0.8 to 1 millimeter or is ulcerated. The result helps with staging and with decisions about further treatment.

It can. About 1 in 10 people with melanoma has a close relative who also had it. Shared sun habits and skin type explain part of that. Inherited gene changes, such as in CDKN2A, explain a smaller part.

If a parent, sibling, or child of yours has had melanoma, tell your doctor. Regular skin exams make sense for you.

Basal cell carcinoma is the most common skin cancer. It often looks like a pearly or shiny bump, a pink patch, or a sore that bleeds, heals, and comes back. It shows up most on the face, ears, neck, and other sun-exposed skin.

It grows slowly and almost never spreads to other organs. Left alone, it can grow deep and damage skin, cartilage, and bone, so it should be treated.

Most are removed with surgery. Options include a standard excision, Mohs surgery for the face and other high-risk sites, and scraping with cautery for small low-risk tumors. Some thin, superficial tumors can be treated with a prescription cream or with radiation.

For the rare advanced case, doctors use pills called hedgehog pathway inhibitors (vismodegib or sonidegib). The immunotherapy cemiplimab is an option if those stop working.

Squamous cell carcinoma is the second most common skin cancer. It can look like a rough, scaly red patch, a firm bump, a wart-like growth, or a sore that won't heal. Common sites are the face, ears, lips, scalp, and the backs of the hands.

Most are cured with a simple procedure. A small share spread, and the risk is higher for tumors on the lip or ear, for large or deep tumors, and for people with weakened immune systems.

The medicines that protect a transplanted organ also quiet the immune system, and the immune system normally clears many sun-damaged cells. Transplant recipients have a much higher risk of squamous cell carcinoma, and their tumors tend to behave more aggressively.

Anyone on long-term immune-suppressing medicine should have regular skin exams and be strict about sun protection.

Immunotherapy is now the main option. Cemiplimab, pembrolizumab, and cosibelimab are approved for advanced squamous cell skin cancer that surgery or radiation can't cure. Cemiplimab can also be given after surgery and radiation to lower the chance of the cancer coming back in high-risk cases.

An actinic keratosis is a rough, scaly spot caused by years of sun exposure. You can often feel it before you can see it. It is a precancer. A small percentage turn into squamous cell carcinoma over time, and no one can predict which ones will.

Dermatologists treat them with freezing, prescription creams such as fluorouracil or imiquimod, or light-based therapy.

An atypical mole is a benign mole that looks unusual, either to the eye or under the microscope. It is not cancer, and most never become cancer.

Having several atypical moles does signal a higher lifetime risk of melanoma somewhere on the skin. Regular skin exams are a good idea.

No. Most melanomas appear as new spots on normal-looking skin, so removing harmless moles doesn't lower the risk much. It also leaves scars. Doctors remove a mole when it looks suspicious or is changing.

A better plan is to know your own skin, check it regularly, and have a dermatologist look at anything new, changing, or different from the rest.

New moles are common through young adulthood and become less common with age. A new or changing pigmented spot in an adult deserves more attention than one in a child. Have a dermatologist look at it, especially if it grows, changes color, itches, or bleeds.

Merkel cell carcinoma is a rare, fast-growing skin cancer. It usually appears as a firm, painless, red or purple bump on sun-exposed skin, most often in older adults or people with weakened immune systems. Sun exposure and a common virus called Merkel cell polyomavirus both play a part.

Treatment usually combines surgery and radiation. For advanced disease, the immunotherapies avelumab, pembrolizumab, retifanlimab, and nivolumab can shrink or slow tumors.

Yes. Ocular melanoma is rare and usually starts in the uvea, the middle layer of the eye. Many people have no symptoms, and an eye doctor finds it during a dilated eye exam. Others notice blurred vision, flashes, floaters, or a dark spot on the iris.

Radiation is the most common treatment and often saves the eye. Our article on ocular melanoma covers this in more detail.

The doctor numbs the skin with a small injection and removes part or all of the spot. The 3 common methods are a shave, a punch (a small round cutter), and an excision with stitches. It takes a few minutes in the office.

The sample goes to a laboratory, where a pathologist examines it under a microscope. That exam is what makes the diagnosis.

A dermatopathologist usually does. This is a physician who trained in dermatology or pathology and then completed extra fellowship training in diagnosing skin disease under the microscope. You may never meet this doctor, but their report drives your treatment.

Most results come back within about 1 to 2 weeks. Some cases need special stains, molecular tests, or a second pathologist's opinion, and those add time. A longer wait doesn't mean the news is bad. If you haven't heard back in 2 weeks, call the office that did the biopsy.

In situ means the abnormal cells are confined to the top layer of the skin. Invasive means they have grown deeper. Margins describe the edges of the removed tissue: a negative or clear margin means no tumor at the edge, and a positive margin means tumor reaches the edge, so more may remain.

Melanoma reports also list Breslow depth (thickness in millimeters), ulceration (whether the skin surface over the tumor is broken down), and mitotic rate (how many cells are dividing). Ask your doctor to go through the report with you line by line.

Yes, and it is a reasonable request. Some pigmented lesions are hard to classify even for experts, and the diagnosis decides the treatment. Ask your doctor to send the glass slides to a second dermatopathologist. Laboratories handle these requests routinely.

No. There is no good evidence that a properly performed skin biopsy causes skin cancer to spread. Delaying a biopsy is the larger risk, because the cancer keeps growing while it goes undiagnosed.

In Mohs surgery, the surgeon removes the visible tumor and then takes thin layers of skin one at a time. Each layer is checked under a microscope while you wait. The surgeon stops when no cancer cells remain.

The method gives very high cure rates for many basal cell and squamous cell cancers and spares healthy skin. That matters most on the face, ears, hands, and other tight areas.

Immunotherapy helps your own immune system attack the cancer. The most used drugs are checkpoint inhibitors, which release the natural brakes on immune cells. Examples include pembrolizumab, nivolumab, ipilimumab, and cemiplimab. They are given through a vein every few weeks.

Because they rev up the immune system, they can inflame healthy organs such as the skin, gut, liver, lungs, and hormone glands. Report new symptoms to the care team early.

About half of melanomas carry a mutation in a gene called BRAF. Pills that block BRAF, paired with pills that block a partner protein called MEK, can shrink these tumors quickly. The pairs are dabrafenib with trametinib, vemurafenib with cobimetinib, and encorafenib with binimetinib.

Your oncologist tests the tumor for the mutation first. These drugs don't work without it.

Rarely. Immunotherapy and targeted therapy work better for most patients and have replaced chemotherapy as the first choices for advanced melanoma. Chemotherapy remains an option when those treatments have stopped working.

Ask your oncologist first, since they know your case. You can also search ClinicalTrials.gov by cancer type and location. Trials aren't only a last resort. Many test new treatments at earlier stages. In cancer trials, participants generally receive at least the current standard of care.

A person who has had one skin cancer has a higher risk of another. Expect regular full-skin exams, often every 3 to 12 months at first depending on the type and stage. Keep checking your own skin between visits, and protect it from the sun. Melanoma follow-up may also include lymph node checks and, for higher stages, scans.

The American Academy of Dermatology recommends a sunscreen that is broad-spectrum, water resistant, and SPF 30 or higher. SPF 30 blocks 97% of the sun's UVB rays.

Most people use too little. An adult needs about 1 ounce, enough to fill a shot glass, to cover the body. Apply it 15 minutes before going out. Reapply every 2 hours and after swimming or sweating.

No study in people has shown that sunscreen causes cancer. The evidence that it prevents cancer is strong. In a randomized trial of 1,621 adults in Nambour, Australia, the group assigned to daily sunscreen developed half as many melanomas over the following years as the group that used it at their own discretion (Green and colleagues, Journal of Clinical Oncology, 2011).

If you prefer to avoid chemical filters, mineral sunscreens made with zinc oxide or titanium dioxide are a good choice.

Yes. UV rays pass through clouds. Snow, water, and sand reflect them back at you, and UV is stronger at high altitude. Make sun protection a daily habit on exposed skin.

No. The World Health Organization's cancer agency classifies tanning beds as a cause of cancer in humans, the same category as tobacco. Women younger than 30 are 6 times more likely to develop melanoma if they tan indoors.

A base tan doesn't protect you in any meaningful way. A tan is itself a sign of DNA damage.

Get it from food and supplements. Fatty fish, fortified milk, and fortified cereals all contain vitamin D, and a supplement fills any gap. This route carries no skin cancer risk. Ask your doctor whether you need your level checked.

Shade and clothing do more than most people expect. Seek shade when the sun is strongest, between 10 a.m. and 2 p.m. Wear a wide-brimmed hat, sunglasses with UV protection, and lightweight long sleeves and pants. Clothing with a UPF label has been tested for how much UV it blocks.

Keep babies younger than 6 months out of direct sunlight. Use shade, a brimmed hat, and lightweight clothing that covers the arms and legs. If shade and clothing aren't available, a small amount of mineral sunscreen with SPF 30 or higher can go on exposed skin. Wash it off once you're indoors.

From 6 months on, use sunscreen along with shade and clothing.

They do. Having 5 or more blistering sunburns between ages 15 and 20 raises melanoma risk by 80%. Skin keeps a record of UV damage, so the protection you give children and teenagers pays off decades later.

Use a full-length mirror and a hand mirror in good light. Look at the front and back of your body, then each side with your arms raised. Check your underarms, forearms, palms, and fingernails. Look at the backs of your legs, your feet, between your toes, and your soles. Use the hand mirror for the back of your neck, your scalp (part your hair), your back, and your buttocks.

About half of melanomas are found by patients themselves. Photos help you notice change over time.

It depends on your risk. In April 2023 the US Preventive Services Task Force concluded that the evidence is insufficient to recommend for or against routine skin exams in adults with no symptoms and no personal or family history of skin cancer.

That statement doesn't apply to people at higher risk. If you have had skin cancer, have a close relative with melanoma, have many or atypical moles, or take immune-suppressing medicine, regular exams with a dermatologist make sense. Ask your doctor how often.

Make an appointment for any spot that is new, changing, or different from your others. The same goes for a spot that itches, hurts, or bleeds without an injury, a sore that hasn't healed in about 4 weeks, a fast-growing bump, or a new dark band under a nail.

Don't wait to see whether it gets worse. When you call, say that the spot is changing. Many offices schedule those visits sooner.

No. The American Melanoma Institute is an education and research nonprofit and doesn't provide medical care. No one can diagnose a skin spot from a description, and a photo alone is not enough either. Please see a board-certified dermatologist. The American Academy of Dermatology has a searchable directory at find-a-derm.aad.org.

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