Basal Cell Carcinoma

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is basal cell carcinoma?

Skin cancer is the most common type of cancer in the United States. And basal cell carcinoma is the most common form of skin cancer. Every year, nearly 4.5 million Americans find out they have basal cell skin cancer. By comparison, there are about 1 million cases per year of squamous cell carcinoma—the second most common skin cancer.

Most skin cancers occur in the epidermis—the outermost layer of the three layers of your skin. Cells in the epidermis are constantly growing, dividing, and making new skin cells. This growth starts at the base, or basal level of the epidermis. As the cells migrate up through the epidermal layer, they flatten into squamous cells. They eventually slough off after they die. Basal cell carcinoma develops in the base layer of the epidermis.

Skin cancer, including basal cell carcinoma, occurs when lifelong excess UV (ultraviolet) light damages skin cells. UV light exposure comes from the sun or from using indoor tanning beds or lights. The damage results in uncontrolled growth of skin cells.

Basal cell skin cancer usually takes many years to develop. Typically, it shows up in people over the age of 50. However, using indoor UV tanning can speed up the process and cause it to develop in younger people. Your risk of basal cell skin cancer is higher if you have a light complexion, light hair, freckles, or a tendency to burn easily.

While it can develop anywhere on the body, basal cell skin cancer most commonly occurs on sun-exposed skin. It can look like a dome-shaped growth or a flat growth that resembles a scar. In some cases, basal cell carcinoma causes lesions that look like sores that bleed and crust, but don’t heal. It can also look like a scaly red or pink patch.

In the early stages, basal cell skin cancer is highly treatable because it grows slowly and usually doesn’t spread. Surgical removal is the main basal cell carcinoma treatment. There are a few different techniques doctors can use, depending on where and how extensive the cancer is. Sometimes, doctors use alternate treatments, such as light therapy or cryotherapy (freezing). Radiation therapy may be an option when surgery isn’t possible. Left untreated, basal cell skin cancer can invade other tissues and become disfiguring.

See your doctor promptly if you notice something new or changing on your skin. If you are at high risk of developing skin cancer or have already had it, talk with your doctor about professional screenings and how often you need them.

What are the symptoms of basal cell carcinoma?

Basal cell cancer usually develops on skin that has had significant UV radiation exposure. It’s most common on the head and neck. However, it can appear anywhere, even on the palms of the hands.

Common basal cell carcinoma symptoms

Basal cell skin cancer can have several different appearances. Most commonly, it looks like a shiny, red, raised growth. It’s easy to mistake it for a pimple or a harmless bump. It can also look flat like a scar. Here are seven warning signs of basal cell cancer from the American Academy of Dermatology:

  • Growth or scaly patch on or near the ear
  • Pink or reddish area that dips in the center
  • Round growth that is skin-colored or may be pink, red, brown, black or tan
  • Scar-like lesion that may be skin-colored, white or yellow and may appear waxy or shiny
  • Scaly patch that may be slightly raised and look irritated
  • Sore that bleeds or crusts, but never heals
  • Spot that feels scaly or looks like an age spot

Some people have symptoms on the affected patch of skin, such as itchiness or numbness.

See your doctor if you notice a new spot, bump or patch that isn’t going away or that changes or grows with time. A dermatologist is best able to tell the difference between a concerning area and a normal skin change. People at higher risk for skin cancer should see a dermatologist on a regular basis for skin checks.

What causes basal cell carcinoma?

Cancers, including basal cell skin cancer, start when cells grow out of control. This happens when genes that normally control cell growth change or mutate. Sometimes, these mutations are inherited. Other times, people acquire and accumulate the mutations over their lifetime. What triggers these acquired changes is not always clear. In fact, most cancers don’t have a definite and defined trigger. Cancer-causing mutations can happen spontaneously, by chance.

Unlike most other cancers, basal cell carcinoma has a known trigger or cause—UV light exposure. Excess UV light causes the damage to cells that results in them becoming cancerous. Each time the skin encounters UV light, a little bit of damage occurs. With time, the cumulative damage builds until the body can no longer repair it. The more exposure you have, the faster the damage can occur.

What are the risk factors for basal cell carcinoma?

The main risk factor for developing basal cell skin cancer is excess UV light exposure from the sun or indoor tanning beds or lights. Living in areas with intense year-round sunlight may contribute to your overall UV exposure and skin cancer risk. Other basal cell carcinoma risk factors include:

  • Age over 50 years
  • Fair skin or skin that freckles or burns easily, but rarely tans
  • History of skin cancer or blistering sunburns in your youth
  • Light hair or eyes
  • Weakened immune system

Reducing your risk of basal cell carcinoma

Because basal cell skin cancer has a known trigger, it is a highly preventable disease. The key to lowering your risk is avoiding exposure to UV light. You can limit UV light damage to your skin by:

  • Avoiding indoor tanning—opt for a self-tanner product instead
  • Choosing indoor activities when the UV index is high
  • Covering up with protective clothing, including accessories such as hats and sunglasses
  • Seeking shade when outside and scheduling outdoor activities before 10:00 a.m. or after 4:00 p.m.
  • Using a daily UVA/UVB sunscreen with an SPF (sun protection factor) of at least 30

None of these methods will provide complete protection. So, the best approach is to combine them. Be extra cautious when reflection can intensify the sun’s light. This includes activities around water, sand or snow.

As part of your skin cancer defense, you should perform self-exams of your skin on a routine basis. Add a professional skin check if you are at increased risk. Also, talk with your doctor or pharmacist about your medications. Some of them may make your skin more sensitive to the sun and more likely to burn, causing damage.

How is basal cell carcinoma treated?

Basal cell carcinoma treatment depends on the stage of the cancer. In the early stages, basal cell skin cancer is highly treatable and almost always curable. The main treatment for most basal cell cancers is surgery to remove the cancer. Surgical techniques include:

  • Excision to cut out the cancer and some normal skin surrounding it
  • Mohs surgery, which removes the cancer layer by layer until no cancer cells are present under a microscope. This approach is very useful in areas with thin skin or where the cosmetic result is a concern.
  • Curettage and electrodessication, which scrapes away the growth and then destroys any remaining cancer cells with electrical current. This approach is most useful when the cancer is on the trunk or limbs (and the cosmetic result is not as important).

For some patients, doctors recommend an alternative to surgery. The two main nonsurgical options are cryotherapy, which freezes off the growth, and photodynamic therapy, which is light therapy with a special chemical treatment.

Doctors may prescribe a medicated cream to use before or after surgery. These are basically chemotherapy creams. Using them for several weeks before surgery can decrease the size of the cancer. This reduces the amount of skin the doctor must remove. After surgery, the cream helps kill any remaining cancer cells. In some cases, these creams are the only treatment.

When areas are hard to treat with surgery, radiation therapy may be an option.

What are the potential complications of basal cell carcinoma?

Basal cell cancer grows slowly and rarely spreads to other areas of the body. However, this doesn’t mean it isn’t a potentially dangerous cancer. Left untreated, it can grow deep into the tissues underlying it. It can destroy bone and other tissues in its path, causing functional deformity and disfigurement. Early detection and treatment is the key to curing basal cell carcinoma and preventing these complications.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jun 25
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