Skin Cancer

What is skin cancer?

Skin cancer is a disease in which cells in the skin begin to grow in an uncontrolled way and form a tumor (an abnormal mass of tissue). It is the most common type of cancer worldwide. Most skin cancers develop in areas of skin that have been exposed to the sun over many years, such as the face, ears, neck, scalp, arms and hands, although they can appear anywhere on the body, including places that are rarely exposed to sunlight.

The three most common types are named after the skin cells in which they start:

• Basal cell carcinoma starts in the basal cells, which sit at the bottom of the outer layer of skin (the epidermis). It is the most common type, tends to grow slowly and rarely spreads to other parts of the body.
• Squamous cell carcinoma starts in the squamous cells, the flat cells that make up most of the epidermis. It is usually treatable but is somewhat more likely than basal cell carcinoma to grow deeper or spread if left untreated.
• Melanoma starts in melanocytes, the cells that make pigment (melanin) and give skin its color. It is less common than the other two types but is more likely to spread (metastasize) to lymph nodes and other organs, which is why early detection matters so much.

Basal cell and squamous cell carcinoma are often grouped together as non-melanoma skin cancer. There are also rarer forms, such as Merkel cell carcinoma and cancers that start in skin glands, but these are uncommon.

Skin cancer can affect anyone, at any age and of any skin color. It is more frequent in adults over 50, in people with fair skin and in people who have had a lot of sun exposure or have used tanning beds. People with darker skin develop skin cancer less often, but when they do, it is sometimes found at a later stage because it may appear in less obvious places, such as the palms, soles or under the nails.

Skin cancer symptoms

Skin cancer symptoms are almost always something you can see or feel on the skin. The most important sign is a change: a new spot, or an existing mole or patch that looks different from before. Skin cancer is usually painless in its early stages, so the absence of pain does not mean a spot is harmless.

Common signs include:

• A new growth, bump, lump or patch that does not go away after several weeks
• A sore that does not heal, or that heals and then comes back
• A spot that bleeds, crusts, oozes or becomes scaly without an obvious cause
• A mole that changes in size, shape, color or texture
• A pearly, waxy or translucent bump, sometimes with visible small blood vessels
• A flat, firm, pale or yellowish area that looks like a scar
• A rough, red, scaly patch that may itch or feel tender
• A dark streak under a fingernail or toenail that is not caused by injury

Symptoms often differ by type. Basal cell carcinoma frequently appears as a shiny, skin-colored or pink bump, a pinkish patch or a sore that keeps reopening. Squamous cell carcinoma more often looks like a firm red nodule, a scaly crusted patch or an open sore with raised edges. Melanoma usually shows up as a new dark spot or a change in an existing mole.

Doctors often teach the ABCDE rule to help people recognize possible melanoma:

• A – Asymmetry: one half of the spot does not match the other half.
• B – Border: the edges are ragged, notched or blurred.
• C – Color: the color is uneven, with shades of brown, black, pink, red, white or blue.
• D – Diameter: the spot is larger than about 6 millimeters (roughly the size of a pencil eraser), although melanomas can be smaller.
• E – Evolving: the spot is changing in size, shape, color or symptoms such as itching or bleeding.

Another useful clue is the "ugly duckling" sign: a mole that simply looks different from all the others on your body. In later stages, if a skin cancer has spread, people may notice swollen lymph nodes (small glands in the neck, armpit or groin), unexplained weight loss or tiredness, but these are much less common and usually occur only in advanced melanoma.

Causes and risk factors

The main cause of skin cancer is damage to the DNA (the genetic instructions inside cells) by ultraviolet (UV) radiation. UV radiation comes mainly from the sun and from artificial sources such as tanning beds and sunlamps. Over time, this damage can build up and cause skin cells to grow out of control. Both long-term daily sun exposure and short, intense episodes that cause sunburn are linked to skin cancer, and severe sunburns in childhood appear to be especially important for melanoma risk.

Not every skin cancer is caused by UV light. Some develop in skin that is rarely exposed to the sun, and genetics, immune function and other factors also play a role. Known skin cancer causes and risk factors include:

• Sun exposure and sunburn history, especially repeated blistering sunburns
• Tanning bed use, particularly before the age of 30
• Fair skin, light hair and light eyes, and skin that freckles or burns easily
• Many moles or unusual (atypical) moles, which raise melanoma risk
• A personal history of skin cancer, which makes a second skin cancer more likely
• A family history of melanoma or certain inherited conditions
• A weakened immune system, for example after an organ transplant, with HIV or during long-term treatment with drugs that suppress immunity
• Older age, because DNA damage accumulates over a lifetime
• Previous radiation therapy to an area of skin
• Exposure to certain chemicals, such as arsenic, or long-standing scars, burns and chronic wounds
• Precancerous skin changes such as actinic keratosis (rough, scaly patches caused by sun damage), which can sometimes progress to squamous cell carcinoma

Having one or more risk factors does not mean you will develop skin cancer, and some people develop it with no obvious risk factors at all. Skin cancer is not contagious and cannot be passed from one person to another.

Skin cancer diagnosis

Skin cancer diagnosis begins with a careful skin examination. A doctor, often a dermatologist (a skin specialist), looks at the suspicious area and usually the rest of your skin as well. They may use a dermatoscope, a handheld magnifying device with a light, to see the structure and color pattern of a spot in more detail. In many clinics, digital photographs are taken so that changes can be compared over time.

Looking at the skin alone is not enough to confirm cancer. The only way to know for certain is a skin biopsy, in which a small sample of the suspicious skin is removed under local anesthetic (medicine that numbs the area) and examined under a microscope by a pathologist (a doctor who specializes in diagnosing disease from tissue samples). Common biopsy types include:

• Shave biopsy, where the top layers of the spot are shaved off with a small blade
• Punch biopsy, where a small round tool removes a deeper core of skin
• Excisional biopsy, where the whole spot and a small margin of surrounding skin are cut out

The pathology report states whether cancer is present, which type it is and, for melanoma, how deep it has grown (the Breslow thickness) and whether the surface is broken (ulcerated). These details help doctors decide on the stage of the cancer, which describes how far it has grown or spread.

For most basal cell and squamous cell carcinomas, no further tests are needed after the biopsy. For melanoma, or for squamous cell carcinoma that is large or high-risk, your doctor may recommend additional tests to check whether the cancer has spread:

• Lymph node examination by hand, and sometimes ultrasound of nearby lymph nodes
• Sentinel lymph node biopsy, a procedure that identifies and removes the first lymph node the cancer would be likely to reach, to see whether it contains cancer cells
• Imaging scans such as CT (computed tomography), MRI (magnetic resonance imaging) or PET (positron emission tomography) scans, usually reserved for more advanced disease
• Blood tests, which do not diagnose skin cancer but may be used to check general health or monitor advanced melanoma

Staging systems differ slightly by cancer type, but in general stage 0 means the cancer is confined to the top layer of skin, stages I and II mean it is limited to the skin, stage III means it has reached nearby lymph nodes and stage IV means it has spread to distant organs.

Skin cancer treatment options

Skin cancer treatment options depend on the type of cancer, its size and location, how deep it has grown, whether it has spread and your general health and preferences. Most skin cancers are found early, when they are confined to the skin, and in these cases treatment is often relatively simple. Care is usually shared between dermatologists, surgeons and, when needed, cancer specialists such as those in a Medical Oncology Department.

Surgical procedures are the most common treatment for all types of skin cancer:

• Surgical excision removes the cancer together with a margin of healthy skin. The wound is then closed with stitches or, for larger areas, a skin graft or flap.
• Mohs surgery removes the cancer in thin layers, with each layer checked under a microscope during the procedure until no cancer cells remain. It is often used for basal and squamous cell carcinomas on the face or in other areas where saving healthy tissue matters.
• Curettage and electrodesiccation scrapes away the cancer and then uses an electric needle to destroy any remaining cells. It may be suitable for small, low-risk non-melanoma skin cancers.
• Cryotherapy freezes the abnormal tissue with liquid nitrogen and is sometimes used for very superficial cancers and precancerous lesions.

Topical medications (creams applied to the skin) may be an option for certain very superficial basal cell carcinomas, early squamous cell carcinoma confined to the top layer of skin, and actinic keratoses. Examples include imiquimod, which stimulates the immune system, and fluorouracil, a chemotherapy cream. Photodynamic therapy, which combines a light-sensitizing medication with a special light, is another option for some superficial lesions.

Radiation therapy uses high-energy beams to destroy cancer cells. It may be recommended when surgery is not possible or desirable, for example in older patients or in difficult locations, or after surgery when there is a risk that some cancer cells remain.

For melanoma, treatment depends heavily on stage. Early melanoma is usually treated with wide surgical excision alone. If the cancer has reached the lymph nodes or spread further, systemic treatments (medicines that work throughout the body) may be recommended:

• Immunotherapy uses drugs that help the immune system recognize and attack cancer cells. It has become a standard treatment for advanced melanoma and is also used after surgery in some higher-risk cases to lower the chance of the cancer returning.
• Targeted therapy uses drugs that block specific genetic changes found in some melanomas, such as mutations in the BRAF gene. Tumor testing is needed to see whether these drugs are likely to work.
• Chemotherapy is used less often for melanoma today but may still have a role in certain situations.

Advanced squamous cell carcinoma that cannot be treated with surgery or radiation may also be treated with immunotherapy or, less commonly, chemotherapy.

Observation is rarely appropriate for a confirmed skin cancer, but a doctor may suggest monitoring a low-risk spot or precancerous change rather than treating it immediately, particularly in people with other serious health problems. After treatment, rehabilitation and reconstruction may be part of care, for example scar management, physical therapy after lymph node surgery, or reconstructive procedures to restore appearance and function.

All treatments carry possible side effects, ranging from scarring and wound infection after surgery to skin changes after radiation and immune-related reactions with immunotherapy. Your care team should explain the expected benefits and risks of each option so that you can take part in the decision.

Living with skin cancer and outlook

For most people, the outlook after skin cancer is favorable. Basal cell and squamous cell carcinomas are usually cured with local treatment, especially when found early. Early-stage melanoma that is thin and has not spread is also very treatable. The outlook becomes more uncertain when melanoma has grown deeper or reached lymph nodes or other organs, although newer immunotherapy and targeted drugs have improved outcomes for many people with advanced disease. No doctor can promise a particular result, and prognosis always depends on the individual situation.

Having one skin cancer raises the risk of developing another, so long-term follow-up is a normal part of care. Your doctor will usually recommend regular skin checks, more frequent in the first few years, and will show you how to examine your own skin at home. Anyone who has had melanoma may also have periodic lymph node checks and, in higher-stage disease, imaging scans.

Day to day, living well after skin cancer often means adopting careful sun habits: seeking shade during the middle of the day, wearing protective clothing and a wide-brimmed hat, using broad-spectrum sunscreen and avoiding tanning beds. These steps lower the risk of new cancers but do not remove it entirely. Many people find the emotional side of a cancer diagnosis, including worry about recurrence and concern about scars, just as challenging as the physical side; talking with your care team, a counselor or a support group can help. Acibadem hospitals, like most large centers, manage skin cancer through a combination of dermatology, surgery and oncology services.

Frequently asked questions

What does skin cancer look like when it starts?

Early skin cancer often looks quite ordinary: a small shiny bump, a pink or red scaly patch, a sore that does not heal or a mole that has begun to change. Because it is usually painless at first, many people ignore it. The key clue is persistence or change over weeks rather than any single appearance, which is why unusual spots are best assessed by a doctor.

What are the most common skin cancer causes?

The leading cause is ultraviolet radiation from the sun and tanning beds, which damages the DNA in skin cells over time. Other contributing factors include fair skin, a family history of melanoma, a weakened immune system, previous radiation and certain chemical exposures. In many cases several factors act together, and some skin cancers arise without a clear cause.

How is skin cancer diagnosis confirmed?

A doctor first examines the skin, often with a dermatoscope. If a spot looks suspicious, a small sample is removed in a biopsy and examined under a microscope. This is the only way to confirm the diagnosis and identify the type. For melanoma or high-risk cancers, further tests such as lymph node assessment or imaging scans may be used to check whether the cancer has spread.

Is skin cancer curable?

Many skin cancers are curable, particularly basal cell and squamous cell carcinomas and early melanoma, which are usually removed completely with surgery. Advanced melanoma that has spread is harder to cure, although modern treatments can control it for long periods in some people. Outcomes vary from person to person, so your doctor can give you the most realistic picture for your situation.

What are the main skin cancer treatment options?

Surgery is the most common treatment and is often the only treatment needed. Other options, depending on the type and stage, include Mohs surgery, curettage, cryotherapy, topical creams, photodynamic therapy and radiation therapy. Advanced melanoma and some advanced squamous cell cancers may be treated with immunotherapy, targeted therapy or, less often, chemotherapy.

Can skin cancer spread to other parts of the body?

Basal cell carcinoma very rarely spreads, though it can grow deeper and damage nearby tissue if untreated. Squamous cell carcinoma spreads occasionally, especially when it is large, deep or on the lips or ears. Melanoma is the type most likely to spread, typically first to nearby lymph nodes and then potentially to the lungs, liver, brain or bones, which is why early detection is emphasized.

Does skin cancer itch or hurt?

Some skin cancers itch, feel tender or bleed, but many cause no sensation at all, particularly in the early stages. Pain or itching alone does not indicate cancer, and its absence does not rule cancer out. Any spot that is new, changing or not healing deserves a medical assessment regardless of how it feels.

When to see a doctor

Most skin changes are harmless, but skin cancer is far easier to treat when it is caught early. Arrange a medical assessment if you notice any of the following red-flag signs:

• A sore or spot that has not healed within about four weeks
• A mole or patch that is changing in size, shape, color or thickness
• A spot that bleeds, oozes, crusts or scabs repeatedly without injury
• A mole that looks different from your other moles, or that meets one or more ABCDE criteria
• A new dark streak under a fingernail or toenail that is not explained by an injury
• A shiny, pearly or waxy bump, or a firm red nodule, that keeps growing
• A new lump or swelling in the neck, armpit or groin, especially if you have had melanoma before
• Any skin change that worries you, particularly if you have a personal or family history of skin cancer

If you have already been treated for skin cancer, seek prompt advice about any new or recurring lesion, redness or swelling at the treatment site, or symptoms such as unexplained weight loss, persistent fatigue or new pain. A doctor can examine the area, perform a biopsy if needed and confirm whether treatment is required.