What Causes Skin Cancer?
Skin cancer is caused by mutations that occur in skin cell DNA, which then cause the abnormal cells to multiply out of control. Ultraviolet (UV) radiation is the most common cause of the DNA mutations that cause skin cancer. UV radiation is found in sunlight and tanning lamps and beds.
Individuals who do not spend much time in the sun or in tanning beds may still get skin cancer. These individuals may be genetically predisposed to skin cancer, may have been affected by toxic substances (arsenic, for example), or may have weakened immune systems that increase their likelihood of acquiring cancer. Those who have received radiation treatment for other skin issues may also be at greater risk for skin cancer (Mayo).
What Are the Types of Skin Cancer?
There are three main types of skin cancer: squamous cell carcinoma, basal cell carcinoma, and melanoma.
Your skin has multiple layers: the upper, protective layer of the skin is known as the epidermis. The epidermis is comprised of three types of cells (squamous cells, basal cells, and melanocytes) that are constantly shedding to make way for fresh, new skin cells.
Squamous cells are the cells nearest to the skin’s surface, and their purpose is to line the skin. Basal cells sit below the squamous cells, and they are continually dividing to form new cells. Melanocytes sit low in the epidermis and are responsible for producing melanin—the pigment that gives skin its color.
Your diagnosis and treatment will depend on in which layer the skin cancer formed.
What Is Squamous Cell Cancer?
Squamous cell cancer (SCC), also called squamous cell carcinoma or nonmelanoma skin cancer, is a type of skin cancer that begins in the squamous cells of the epidermis. This cancer is caused by mutations in the DNA of these cells, which cause them to multiply uncontrollably.
According to the Skin Cancer Foundation, SCC is the second most common form of skin cancer. Each year in the United States, approximately 700,000 individuals are diagnosed with this type of skin cancer (SCF).
SCC can develop anywhere, but it is most often found in areas that receive sun exposure.
What Are the Risk Factors for Squamous Cell Cancer?
Risk factors for squamous cell carcinoma include:
- fair skin
- long-term sun exposure
- multiple severe sunburns, especially early in life
- exposure to chemicals, such as arsenic
- having light hair and blue, green, or gray eyes
African Americans are not exempt from this cancer; in fact, the majority of skin cancers in this population are SCCs (SCF). In African Americans, SCCs usually develop on skin with a pre-existing condition or on burn sites.
Symptoms of Squamous Cell Cancer
This cancer often occurs in areas exposed to the sun, but can also appear in the mouth, in the anal area, and on the genitals. In its early stages, SCC often looks like a scaly, reddish patch of skin. As it progresses, it can turn into a bump that continues to grow. The bump may also bleed. In the mouth, this cancer will take on the appearance of a mouth ulcer or a white patch.
Sometimes, you will notice a new growth on a pre-existing scar, mole, birthmark, or wart. Any lesions or sores that are not healing can also signal SCC.
If you notice any of the above symptoms, make an appointment with your doctor or a dermatologist (skin doctor).
How Is Squamous Cell Cancer Diagnosed?
First, your doctor will check your body for areas of suspicion. He or she will then examine any abnormal areas and may decide to take a biopsy.
A biopsy usually involves shaving off a very small portion of the affected skin for testing and diagnosis. Sometimes, the doctor may need to remove a larger part or all of the abnormal growth for testing. Talk to your doctor about any potential scarring or biopsy concerns.
Treatment for Squamous Cell Cancer
Treatment for SCC varies. Treatment is based on the extent and severity of the cancer, your age and overall health, and the location of the cancer. If caught early, SCC can be successfully eradicated. It becomes harder to cure once it has spread. Many treatments can be performed as in-office procedures.
- Mohs micrographic surgery (or Mohs surgery) uses a scalpel to remove the abnormal skin and some surrounding tissue. The sample is immediately examined microscopically. If there are any cancer cells in the sample, the process is repeated until there is no cancer seen under the microscope.
- Excisional surgery removes the cancer, along with a perimeter of healthy skin. Stitches are used to close the wound. The sample is then sent to a laboratory to ensure the entire cancerous area has been removed.
- Electrosurgery, also called curettage and electrodessication, involves scraping off the cancer and cauterizing (burning) the skin. The cauterization also helps to kill cancer cells. This is typically done more than once to ensure thorough treatment and complete removal of the cancer.
- Cryosurgery freezes the cancerous tissue, which kills the cancer cells. This is done with liquid nitrogen. Like electrosurgery, it is repeated to ensure all cancerous tissue has been destroyed.
- Radiation uses high-energy X-rays to kill cancer cells. It is administered externally by a machine that aims the rays at the intended spot. This is performed multiple times a week for several weeks.
There are also several treatments that have not yet been FDA-approved for SCC. These include photodynamic therapy, laser surgery, and topical medications.
Photodynamic therapy, or PDT, involves the application of a photosensitizing substance on the cancerous areas. The following day, the areas that were medicated go under a strong light. This activates the medication that was applied and kills abnormal cells.
Laser surgery uses a laser to remove areas of skin that are abnormal.
Topical medications that are used to treat other skin cancers are also being considered to help treat SCC.
Once your SCC has been treated, it is important to have follow-up visits with your doctor. SCC can return, and it is important to monitor your skin at least once a month for any precancerous or cancerous areas.
Preventing Squamous Cell Cancer
To help reduce your risk of SCC, follow these tips:
- Limit your sun exposure.
- Avoid the sun in the hottest part of the day, between 10 a.m. and 4 p.m.
- Wear sunscreen and lip balm of at least SPF 15 any time you go out in the sun.
- Wear sunglasses with UV ray protection.
- Consider wearing a hat when working outside for long periods.
- Avoid using tanning beds and lamps.
- Protect your skin during the wintertime as well. Winter rays can be especially dangerous.
- Check your skin each month for any abnormal or new growths.
- See a dermatologist once a year for a full-body skin check.
Outlook for Squamous Cell Cancer
Early detection of SCC is key to successful treatment. If not treated in its early stages, this cancer may spread to other areas of the body, including the lymph nodes and organs. This could be fatal.
Those with weakened immune systems due to organ transplants, HIV/AIDS, or leukemia are at greater risk for more serious forms of SCC.