ConditionCancer
Skin Cancer
Skin cancer is the uncontrolled growth of abnormal skin cells, usually triggered by ultraviolet (UV) damage from the sun or tanning beds. It is the most common cancer in the US. The three main types are basal cell carcinoma, squamous cell carcinoma and melanoma, the most dangerous. Warning signs include a new or changing spot, a sore that will not heal, or a pearly, scaly or dark growth. Found early, nearly all skin cancers are curable, usually with minor surgery.
Also called: Cutaneous malignancy, skin carcinoma, non-melanoma skin cancer, keratinocyte carcinoma, melanoma
At a glance
- What it is
- Cancer arising from skin cells, mostly due to UV damage.
- Main types
- Basal cell carcinoma (most common), squamous cell carcinoma, melanoma (most deadly), plus rarer Merkel cell carcinoma and others.
- Warning signs
- New or changing spot, a sore that does not heal, pearly bump, scaly red patch, irregular mole.
- Diagnosis
- Skin exam, dermoscopy and biopsy.
- Treatment
- Excision, Mohs surgery, topical treatments, radiation; immunotherapy and targeted therapy for advanced disease.
When to get help
See a doctor within a day or two
- A mole or dark spot that is rapidly growing, bleeding, raised or changing over weeks
- A fast-growing, firm, red or skin-colored lump, especially on the head and neck in an older adult
- A known skin cancer with new lumps in the neck, armpit or groin
Book a routine appointment
- A mole with any ABCDE warning sign, or one that looks different from your other moles
- A sore, scab or pimple that has not healed in 4 weeks or keeps bleeding
- A pearly or shiny bump, or a scaly red patch that persists
- A dark streak under a fingernail or toenail that is new or widening
- Many moles, a history of severe sunburns, or a family history of melanoma (ask about regular skin checks)
Types of skin cancer
| Type | Share of skin cancers | How it looks | Behavior |
|---|---|---|---|
| Basal cell carcinoma (BCC) | About 8 in 10 | Pearly or waxy bump, pink shiny patch, sore that bleeds and scabs, scar-like area; often on face and neck | Grows slowly, rarely spreads, but can damage nearby tissue |
| Squamous cell carcinoma (SCC) | About 2 in 10 | Firm red nodule, scaly crusted patch, sore that does not heal, wart-like growth; sun-exposed areas, lips, ears | Can spread, especially from lips, ears or in immunosuppressed people |
| Melanoma | About 1% of skin cancers, but most skin cancer deaths | New or changing mole, irregular shape and color; can appear anywhere, including palms, soles, nails | Can spread early; highly curable when thin |
| Merkel cell carcinoma | Rare | Fast-growing, firm, painless red or purple bump | Aggressive |
| Others | Rare | Kaposi sarcoma, cutaneous lymphoma, dermatofibrosarcoma protuberans | Varies |
Precancerous lesions
- Actinic keratosis: rough, scaly spots on sun-damaged skin that can turn into SCC
- Bowen disease (SCC in situ): a red, scaly patch confined to the top skin layer
- Dysplastic (atypical) nevi: markers of increased melanoma risk
Early signs: what to look for
The ABCDEs of melanoma
- Asymmetry: the two halves do not match
- Border: irregular, ragged or blurred
- Color: varied shades of brown, black, tan, red, white or blue
- Diameter: larger than 6 mm (a pencil eraser), though melanomas can be smaller
- Evolving: changing in size, shape, color or height, or new symptoms such as bleeding or itching
Also watch for the ugly duckling: a spot that looks different from all your other moles.
Signs of basal and squamous cell carcinoma
- a shiny, pearly or translucent bump
- a flat, scaly, red patch that does not go away
- an open sore that bleeds, crusts and heals, then returns
- a firm, raised, red lump
- a wart-like growth
- a scar-like area with no injury
Risk factors
- UV exposure: cumulative sun exposure (BCC, SCC) and intense, blistering sunburns, especially in childhood (melanoma)
- tanning beds
- fair skin, light hair and eyes, freckles, burning easily
- many moles or atypical moles
- personal or family history of skin cancer
- age
- weakened immune system, especially organ transplant recipients, who have a much higher SCC risk
- genetic conditions such as xeroderma pigmentosum and Gorlin syndrome
- radiation exposure and some chemicals (arsenic)
- HPV for some SCCs
People with darker skin get skin cancer less often but are more likely to be diagnosed late. Melanoma in darker skin often appears on the palms, soles and under the nails.
Diagnosis
- full skin examination, including scalp, nails, soles and genitals
- dermoscopy: a lighted magnifier that reveals patterns beneath the surface
- biopsy: shave, punch or excisional biopsy confirms the diagnosis
- staging for melanoma and high-risk SCC: tumor thickness (Breslow depth), ulceration, sentinel lymph node biopsy, and imaging (CT, PET, MRI) for advanced cases
Treatment
Basal and squamous cell carcinoma
- surgical excision with a margin of normal skin
- Mohs surgery: layers are removed and checked under a microscope during the procedure; best for the face and high-risk tumors, with the highest cure rates and maximum tissue preservation
- curettage and electrodesiccation for small, low-risk lesions
- topical treatments (imiquimod, 5-fluorouracil) and photodynamic therapy for superficial BCC and precancers
- radiation therapy when surgery is not possible
- hedgehog inhibitors (advanced BCC) and immunotherapy such as cemiplimab (advanced SCC)
Melanoma
- wide local excision with margins based on thickness
- sentinel lymph node biopsy for thicker melanomas
- immunotherapy (checkpoint inhibitors) and targeted therapy (BRAF and MEK inhibitors) for advanced or high-risk melanoma, which have greatly improved survival
- radiation for some situations
Outlook
BCC and SCC are cured in the vast majority of cases. For melanoma, the 5-year survival rate is above 99% when localized, but falls if it spreads to lymph nodes or distant organs. After any skin cancer, the risk of another is higher, so regular skin checks continue for life.
Prevention
- seek shade, especially between 10 a.m. and 4 p.m.
- wear protective clothing, a wide-brimmed hat and UV-blocking sunglasses
- use broad-spectrum sunscreen SPF 30 or higher, reapplied every 2 hours and after swimming or sweating
- avoid tanning beds
- protect children from sunburn
- do monthly skin self-checks, and see a dermatologist for changing spots
Frequently asked questions
What are the early signs of skin cancer?
Early signs include a new spot or growth, a mole that changes in size, shape or color, a sore that does not heal within 4 weeks, a shiny or pearly bump, a scaly red patch, or a dark streak under a nail.
What are the three main types of skin cancer?
Basal cell carcinoma, squamous cell carcinoma and melanoma. Basal cell carcinoma is the most common and rarely spreads. Squamous cell carcinoma can spread if untreated. Melanoma is less common but the most likely to spread and cause death.
Is skin cancer curable?
Yes, most skin cancers are cured when found early. Basal and squamous cell carcinomas are usually removed with minor surgery. Early melanoma has a very high cure rate, and modern treatments have improved outcomes for advanced melanoma.
How can I prevent skin cancer?
Limit UV exposure: seek shade, wear protective clothing and hats, use broad-spectrum SPF 30 or higher sunscreen, and avoid tanning beds. Check your skin monthly and see a doctor about any new or changing spots.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Dermatology: Skin cancer types: Diagnosis and treatment
- American Cancer Society: Skin cancer facts and statistics
- National Cancer Institute: Skin cancer treatment (PDQ)
- US Preventive Services Task Force: Skin cancer prevention: behavioral counseling
- Skin Cancer Foundation: Skin cancer information
- CDC: Skin cancer prevention