Basal cell carcinoma

Overview

Basal cell carcinoma is a type of skin cancer. Basal cell carcinoma begins in the basal cells — a type of cell within the skin that produces new skin cells as old ones die off.

Basal cell carcinoma often appears as a slightly transparent bump on the skin, though it can take other forms. Basal cell carcinoma occurs most often on areas of the skin that are exposed to the sun, such as your head and neck.

Most basal cell carcinomas are thought to be caused by long-term exposure to ultraviolet (UV) radiation from sunlight. Avoiding the sun and using sunscreen may help protect against basal cell carcinoma.

Symptoms

Basal cell carcinoma usually develops on sun-exposed parts of your body, especially your head and neck. Less often, basal cell carcinoma can develop on parts of your body usually protected from the sun, such as the genitals.

Basal cell carcinoma appears as a change in the skin, such as a growth or a sore that won't heal. These changes in the skin (lesions) usually have one of the following characteristics:

A shiny, skin-colored bump that's translucent, meaning you can see a bit through the surface. The bump can look pearly white or pink on white skin. On brown and Black skin, the bump often looks brown or glossy black. Tiny blood vessels might be visible, though they may be difficult to see on brown and Black skin. The bump may bleed and scab over.
A brown, black or blue lesion — or a lesion with dark spots — with a slightly raised, translucent border.
A flat, scaly patch with a raised edge. Over time, these patches can grow quite large.
A white, waxy, scar-like lesion without a clearly defined border.

When to see a doctor

Make an appointment with your health care provider if you observe changes in the appearance of your skin, such as a new growth, a change in a previous growth or a recurring sore.

Causes

Basal cell carcinoma occurs when one of the skin's basal cells develops a mutation in its DNA.

Basal cells are found at the bottom of the epidermis — the outermost layer of skin. Basal cells produce new skin cells. As new skin cells are produced, they push older cells toward the skin's surface, where the old cells die and are sloughed off.

The process of creating new skin cells is controlled by a basal cell's DNA. The DNA contains the instructions that tell a cell what to do. The mutation tells the basal cell to multiply rapidly and continue growing when it would normally die. Eventually the accumulating abnormal cells may form a cancerous tumor — the lesion that appears on the skin.

Ultraviolet light and other causes

Much of the damage to DNA in basal cells is thought to result from ultraviolet (UV) radiation found in sunlight and in commercial tanning lamps and tanning beds. But sun exposure doesn't explain skin cancers that develop on skin not ordinarily exposed to sunlight. Other factors can contribute to the risk and development of basal cell carcinoma, and the exact cause may in some cases not be clear.

Risk factors

Factors that increase your risk of basal cell carcinoma include:

Chronic sun exposure. A lot of time spent in the sun — or in commercial tanning beds — increases the risk of basal cell carcinoma. The threat is greater if you live in a sunny or high-altitude location, both of which expose you to more UV radiation. Severe sunburns also increase your risk.
Radiation therapy. Radiation therapy to treat acne or other skin conditions may increase the risk of basal cell carcinoma at previous treatment sites on the skin.
Fair skin. The risk of basal cell carcinoma is higher among people who freckle or burn easily or who have very light skin, red or blond hair, or light-colored eyes.
Increasing age. Because basal cell carcinoma often takes decades to develop, the majority of basal cell carcinomas occur in older adults. But it can also affect younger adults and is becoming more common in people in their 20s and 30s.
A personal or family history of skin cancer. If you've had basal cell carcinoma one or more times, you have a good chance of developing it again. If you have a family history of skin cancer, you may have an increased risk of developing basal cell carcinoma.
Immune-suppressing drugs. Taking medications that suppress your immune system, such as anti-rejection drugs used after transplant surgery, significantly increases your risk of skin cancer.
Exposure to arsenic. Arsenic, a toxic metal that's found widely in the environment, increases the risk of basal cell carcinoma and other cancers. Everyone has some arsenic exposure because it occurs naturally. But some people may have higher exposure if they drink contaminated well water or have a job that involves producing or using arsenic.
Inherited syndromes that cause skin cancer. Certain rare genetic diseases can increase the risk of basal cell carcinoma, including nevoid basal cell carcinoma syndrome (Gorlin-Goltz syndrome) and xeroderma pigmentosum.

Complications

Complications of basal cell carcinoma can include:

A risk of recurrence. Basal cell carcinomas commonly recur, even after successful treatment.
An increased risk of other types of skin cancer. A history of basal cell carcinoma may also increase the chance of developing other types of skin cancer, such as squamous cell carcinoma.
Cancer that spreads beyond the skin. Very rarely, basal cell carcinoma can spread (metastasize) to nearby lymph nodes and other areas of the body, such as the bones and lungs.

Prevention

To reduce your risk of basal cell carcinoma you can:

Avoid the sun during the middle of the day. In many places, the sun's rays are strongest between about 10 a.m. and 4 p.m. Schedule outdoor activities for other times of the day, even during winter or when the sky is cloudy.
Wear sunscreen year-round. Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Apply sunscreen generously, and reapply every two hours — or more often if you're swimming or perspiring.
Wear protective clothing. Cover your skin with dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than does a baseball cap or visor.

Some companies also sell protective clothing. A dermatologist can recommend an appropriate brand. Don't forget sunglasses. Look for those that block both types of UV radiation — UVA and UVB rays.
Avoid tanning beds. Tanning beds emit UV rays and can increase your risk of skin cancer.
Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks. With the help of mirrors, check your face, neck, ears and scalp.

Examine your chest and trunk and the tops and undersides of your arms and hands. Examine both the front and the back of your legs and your feet, including the soles and the spaces between your toes. Also check your genital area and between your buttocks.

Diagnosis

In order to assess any growths or changes in your skin, your doctor or a specialist in skin conditions (dermatologist) will conduct a medical history and exam.

History and general exam

Your doctor will conduct a general physical exam and ask you questions about your medical history, changes in your skin, or any other signs or symptoms you've experienced.

Questions may include:

When did you first notice this skin growth or lesion?
Has it changed since you first noticed it?
Is the growth or lesion painful?
Do you have any other growths or lesions that concern you?
Have you had a previous skin cancer?
Has anyone in your family had skin cancer? What kind?
Do you take precautions to stay safe in the sun, such as avoiding midday sun and using sunscreen?
Do you examine your own skin on a regular basis?

Skin exam

Your doctor will examine not only the suspicious area on your skin but also the rest of your body for other lesions.

Skin sample for testing

Your doctor may do a skin biopsy, which involves removing a small sample of a lesion for testing in a laboratory. This will reveal whether you have skin cancer and, if so, what type of skin cancer. The type of skin biopsy you undergo will depend on the type and size of the lesion.

Treatment

The goal of treatment for basal cell carcinoma is to remove the cancer completely. Which treatment is best for you depends on the type, location and size of your cancer, as well as your preferences and ability to do follow-up visits. Treatment selection can also depend on whether this is a first-time or a recurring basal cell carcinoma.

Surgery

Basal cell carcinoma is most often treated with surgery to remove all of the cancer and some of the healthy tissue around it.

Options might include:

Surgical excision. In this procedure, your doctor cuts out the cancerous lesion and a surrounding margin of healthy skin. The margin is examined under a microscope to be sure there are no cancer cells.

Excision might be recommended for basal cell carcinomas that are less likely to recur, such as those that form on the chest, back, hands and feet.
Mohs surgery. During Mohs surgery, your doctor removes the cancer layer by layer, examining each layer under the microscope until no abnormal cells remain. This allows the surgeon to be certain the entire growth is removed and avoid taking an excessive amount of surrounding healthy skin.

Mohs surgery might be recommended if your basal cell carcinoma has a higher risk of recurring, such as if it's larger, extends deeper in the skin or is located on your face.

Other treatments

Sometimes other treatments might be recommended in certain situations, such as if you're unable to undergo surgery or if you don't want to have surgery.

Other treatments include:

Curettage and electrodessication (C and E). C and E treatment involves removing the surface of the skin cancer with a scraping instrument (curet) and then searing the base of the cancer with an electric needle.

C and E might be an option for treating small basal cell carcinomas that are less likely to recur, such as those that form on the back, chest, hands and feet.
Radiation therapy. Radiation therapy uses high-energy beams, such as X-rays and protons, to kill cancer cells.

Radiation therapy is sometimes used after surgery when there is an increased risk that the cancer will return. It might also be used when surgery isn't an option.
Freezing. This treatment involves freezing cancer cells with liquid nitrogen (cryosurgery). It may be an option for treating superficial skin lesions. Freezing might be done after using a scraping instrument (curet) to remove the surface of the skin cancer.

Cryosurgery might be considered for treating small and thin basal cell carcinomas when surgery isn't an option.
Topical treatments. Prescription creams or ointments might be considered for treating small and thin basal cell carcinomas when surgery isn't an option.
Photodynamic therapy. Photodynamic therapy combines photosensitizing drugs and light to treat superficial skin cancers. During photodynamic therapy, a liquid drug that makes the cancer cells sensitive to light is applied to the skin. Later, a light that destroys the skin cancer cells is shined on the area.

Photodynamic therapy might be considered when surgery isn't an option.

Treatment for cancer that spreads

Very rarely, basal cell carcinoma may spread (metastasize) to nearby lymph nodes and other areas of the body. Additional treatment options in this situation include:

Targeted drug therapy. Targeted drug treatments focus on specific weaknesses present within cancer cells. By blocking these weaknesses, targeted drug treatments can cause cancer cells to die.

Targeted therapy drugs for basal cell carcinoma block molecular signals that enable the cancers to continue growing. They might be considered after other treatments or when other treatments aren't possible.
Chemotherapy. Chemotherapy uses powerful drugs to kill cancer cells. It might be an option when other treatments haven't helped.

Preparing for your appointment

The following information can help you prepare for an appointment.

What you can do

Write down your medical history, including other conditions for which you've been treated. Be sure to include any radiation therapy you may have received, even years ago.
Note any personal history of exposure to excessive UV light, including sunlight or tanning beds. For example, tell your doctor if you have worked as an outdoor lifeguard or spent lots of time at the beach.
Make a list of immediate family members who have had skin cancer, to the best of your ability. Skin cancer in a parent, grandparent, aunt, uncle or sibling is important history to share with your doctor.
Make a list of your medications and natural remedies. Include any prescription or over-the-counter medications you're taking, as well as all vitamins, supplements or herbal remedies.
Write down questions to ask your doctor. Creating your list of questions in advance can help you make the most of your time with your doctor.
Find a family member or friend who can join you for your appointment. Although skin cancer is usually highly treatable, just hearing the word "cancer" can make it difficult for most people to focus on what the doctor says next. Take someone along who can help take in all the information.

Questions for your doctor

Below are some basic questions to ask your doctor about basal cell carcinoma. If any additional questions occur to you during your visit, don't hesitate to ask.

Do I have skin cancer? What kind?
How is this type of skin cancer different from other types?
Has my cancer spread?
What treatment approach do you recommend?
What are the possible side effects of this treatment?
Will I have a scar after treatment?
Am I at risk of this condition recurring?
Am I at risk of other types of skin cancer?
How often will I need follow-up visits after I finish treatment?
Are my family members at risk of skin cancer?
Are there brochures or other printed material that I can take with me? What websites do you recommend?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to talk about in-depth. Your doctor may ask:

When did you first notice this skin growth or lesion?
Has it grown significantly since you first found it?
Is the growth or lesion painful?
Do you have any other growths or lesions that concern you?
Have you had a previous skin cancer?
Has anyone in your family had skin cancer? What kind?
How much exposure to the sun or tanning beds did you have as a child and teenager?
How much exposure to the sun or tanning beds do you have now?
Are you currently taking any medications, dietary supplements or herbal remedies?
Have you ever received radiation therapy for a medical condition?
Have you ever taken medications that suppress your immune system?
What other significant medical conditions have you been treated for, including in your childhood?
Do you or did you smoke? How much?
Do you now have or have you ever had a job that may have exposed you to pesticides or herbicides?
Do you now use or have you used well water as your primary water source?
Do you take precautions to stay safe in the sun, such as avoiding midday sun and using sunscreen?
Do you examine your own skin on a regular basis?