We all spend time in the sun, which increases our risk of developing squamous cell skin cancer. This is the second most common type of cancer in the United States and typically affects areas of the skin exposed to ultraviolet (UV) rays from the sun, tanning beds, or lamps. The damage from UV exposure is cumulative, so the more exposure you have, the greater your risk of developing this type of cancer.

In some cases, squamous cell carcinoma can also be caused by human papillomavirus (HPV) or exposure to certain types of chemicals or radiation. HPV-related squamous cell carcinomas sometimes appears on the genitals.

The good news is that when caught early, squamous cell carcinoma is often highly treatable. The best outcome occurs when it is caught at the precancerous stage, known as actinic keratosis, before it progresses into cancer.

Squamous cell carcinoma affects the outermost layer of skin and typically appears as a small scaly red or pink spot, often on the face, neck, and top of the hands. If a spot pops up and does not go away within two to three weeks, you should see a doctor. The best way to prevent or minimize squamous cell skin cancer is to cover your skin with protective clothing or sunscreen (50 SPF or higher), to regularly scan your skin for anything unusual, and to schedule annual full-body exams with a dermatologist.

Because the risk increases with sun exposure, people who had frequent sunburns as children are more likely to develop squamous cell skin cancer later in life. This can occur even if you have been careful about protecting your skin for decades. For this same reason, people in their 50s, 60s, and 70s are more likely to develop the condition. However, squamous cell carcinoma takes a long time to grow, so starting to protect your skin at any age can help.

Diagnosis

The first step in diagnosing squamous cell carcinoma is a thorough skin check. This helps identify both actinic keratosis and squamous cell cancer. Actinic keratosis can usually be diagnosed by examining the appearance, texture, and location of the spot.

At the Kimberly and Eric J. Waldman Melanoma and Skin Cancer Center, if we suspect squamous cell carcinoma, we will probably perform a biopsy, which involves removing a small piece of the spot and sending it to the lab for testing. If untreated, squamous cell carcinoma can spread to lymph nodes or other organs (called metastasis).

Treatment

We typically treat actinic keratosis with liquid nitrogen, which destroys the abnormal cells before they have time to grow into cancer. The treated area will form a scab, and once the scab falls off, the abnormal cells are gone, preventing them from developing into skin cancer.

The treatment for squamous cell carcinoma is to surgically remove the cancer. If the cancer is on the face, or a place where you would like to minimize scarring, we might use a procedure called Mohs surgery. This is a multistage process. The procedure involves removing very thin layers of the affected skin and examining each layer under a microscope while you wait. If cancer cells remain, another thin layer is removed and tested until all the cancer is gone. Once the cancer is removed, the chance of it returning is very low—less than one percent. However, new squamous cell carcinomas can still develop. In rare cases, our dermatologist might also use a nonsurgical approach for very tiny carcinomas, including topical medications applied to the skin or radiation therapy. These options are not available in most places, and are only appropriate for specific carcinomas. They might not be as effective as surgery.

Transplant Patients

If you have received an organ transplant, such as a liver, kidney, heart, or lung, you are at a much higher risk of developing squamous cell carcinoma than people who have not undergone a transplant. The chances can be up to 100 times greater, according to the Skin Cancer Foundation. This is due to the type of immunosuppressant medications you take to prevent your body from rejecting the new organ. While we do not know why these particular immunosuppressants lead to squamous cell carcinoma, we are aware that the risk increases with time.

Fortunately, squamous cell carcinoma is highly treatable. We recommend that all transplant patients have an annual skin check, to catch any potential problems early.