Skin cancer is the most common cancer in the United States. Most cases are basal cell or squamous cell carcinomas, which are highly curable. Melanoma is less common but more dangerous, because it can spread to other organs if not caught early. The good news is that skin cancer is visible. Checking your own skin regularly and knowing what to look for can lead to early diagnosis, when cure rates are very high.
Types of skin cancer
Basal cell carcinoma is the most common type. It often appears as a pearly or waxy bump, a flat flesh-colored or brown scar-like patch, or a sore that bleeds, heals and returns. It grows slowly and rarely spreads, but it can damage surrounding tissue if left untreated.
Squamous cell carcinoma often appears as a firm red bump, a scaly patch, or a sore that does not heal, usually on sun-exposed areas. It can occasionally spread if untreated.
Melanoma develops from pigment cells (melanocytes). It can appear as a new spot or a change in an existing mole, and it can occur anywhere, including areas that rarely see the sun, such as the soles of the feet, palms, under nails and, rarely, the eyes.
The ABCDE rule for melanoma
Use this rule when checking moles and spots:
| Letter | Stands for | What to look for |
|---|---|---|
| A | Asymmetry | One half does not match the other |
| B | Border | Edges are irregular, ragged, notched or blurred |
| C | Color | Uneven color with shades of brown, black, tan, red, white or blue |
| D | Diameter | Larger than 6 mm (about the size of a pencil eraser), though melanomas can be smaller |
| E | Evolving | Any change in size, shape, color, height, or new itching, bleeding or crusting |
Doctors also use the “ugly duckling” sign: a mole that looks different from all your other moles deserves attention.
Who is at higher risk
- Fair skin, light hair, and eyes that burn or freckle easily
- A history of sunburns, especially blistering burns in childhood
- Use of tanning beds
- Many moles (more than 50) or unusual-looking (atypical) moles
- A personal or family history of melanoma or other skin cancer
- A weakened immune system, such as after an organ transplant
- Older age, though melanoma is one of the more common cancers in young adults
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People with darker skin get skin cancer less often, but melanoma in people of color is more likely to be diagnosed late, often on the palms, soles or under the nails.
How to check your skin
Check your skin once a month in good light:
- Look at your face, ears, neck and scalp (use a comb and a hand mirror, or ask someone to help).
- Check your chest, belly and, for women, under the breasts.
- Look at your arms, underarms, hands, between your fingers and under your nails.
- Check your back, buttocks and the backs of your legs using a full-length mirror and a hand mirror.
- Check your legs, feet, soles and between your toes.
Take photos of moles you want to monitor so you can compare them over time.
What happens at the doctor
A doctor or dermatologist will examine your skin, often using a dermatoscope, a handheld magnifying light. If a spot looks suspicious, they will take a biopsy, a small sample removed under local anesthetic, to examine under a microscope. This is the only way to confirm skin cancer.
Treatment
Basal and squamous cell carcinomas are usually removed with minor surgery. Mohs surgery, in which thin layers are removed and checked under the microscope until no cancer remains, is used for cancers on the face and other sensitive areas. Other options include freezing, scraping, topical creams and radiation for selected cases.
Melanoma is treated by surgical removal with a margin of healthy skin. Depending on its thickness, a sentinel lymph node biopsy may check whether it has spread. For advanced melanoma, immunotherapy and targeted therapy (for tumors with a BRAF mutation) have dramatically improved survival over the past decade.
When melanoma is found early, before it has spread, the five-year survival rate is above 99 percent.
Prevention
- Seek shade, especially between 10 a.m. and 4 p.m.
- Use broad-spectrum sunscreen with SPF 30 or higher on all exposed skin, and reapply every two hours and after swimming or sweating
- Wear protective clothing, a wide-brimmed hat and UV-blocking sunglasses
- Avoid tanning beds completely
- Protect children from sunburn
- Check your skin monthly and see a dermatologist if you are at high risk
When to see a doctor
See a doctor promptly about any new mole after age 30, any mole that changes, a spot that looks different from the rest, a sore that does not heal within a few weeks, or a dark streak under a nail.
The bottom line
Skin cancer is common but usually curable when found early. Check your skin every month using the ABCDE rule and the ugly duckling sign, protect yourself from UV exposure, and have any new or changing spot checked. Early melanoma has an excellent outlook.
This article is for general information and does not replace a medical examination.