This page was reviewed under our medical and editorial policy by
Frederick L. Durden, Jr, MD, Plastic and Reconstructive Surgeon & Microsurgical Reconstructive Surgeon
This page was updated on October 20, 2022.
Squamous cell carcinoma (SCC) is one of the most common types of skin cancer. About two out of 10 skin cancers are squamous cell carcinomas, according to the American Cancer Society.
The other two main types of skin cancer are basal cell carcinoma and melanoma. Although SCC has a higher survival rate than melanoma, it's important to ensure that any skin cancer is properly diagnosed and treated by an experienced doctor.
This article will cover:
Squamous cell carcinoma starts in the flat squamous cells found in the upper part of the epidermis, the skin's outermost layer.
Squamous cell cancers typically grow slowly, but if left untreated, they may grow deeper into the skin and spread to other areas of the body. That’s why it’s important to get SCC evaluated early, before the cancer has penetrated the outer layer of the skin.
Knowing the signs and symptoms may help patients identify squamous cell carcinoma in its most treatable stages.
These include:
Squamous cell carcinoma may also itch or feel sore. Some patients report numbness or tingling in the area.
This type of skin cancer typically appears on sun-exposed parts of the body, such as the face, ears, neck, lips or the backs of hands. Sometimes it forms in a scaly patch of skin called actinic keratosis or AK, which is caused by sun exposure.
Exposure to the sun's ultraviolet (UV) rays is the leading cause of squamous cell carcinoma and other skin cancers. The UV rays damage the DNA, or genetic material, in the squamous cells, increasing the risk for cancer.
Other factors that may raise SCC risk include:
In people with a darker skin tone, these skin cancers tend to develop in areas that get little or no sun, including the mouth, genitals or anus.
The best way to stay a step ahead of all types of skin cancer, including squamous cell carcinoma, is to schedule yearly visits with a dermatologist. During a skin check, a dermatologist looks for any abnormal area that differs in color, size, shape or texture from the skin around it.
In addition to doctor visits, monthly skin self-exams are recommended. Patients who spot something suspicious that’s growing, bleeding or changing should consult with their dermatologist for follow-up. If needed, the doctor may perform a biopsy and send the cells to the lab for analysis to determine if they’re cancerous.
Squamous cell carcinoma is usually diagnosed early and tends to spread slowly. That said, if it isn’t found and treated early, this type of skin cancer can spread to nearby lymph nodes and other parts of the body.
Squamous cell carcinoma treatment is based on the size and location of the growth, as well as the patient’s overall health.
Squamous cell carcinoma is often removed surgically via excision (the doctor cuts out the tumor and stitches up the skin).
Mohs micrographic surgery is often used for aggressive, large or recurrent squamous cell cancers. It may be an option for squamous cell carcinoma that’s spreading along nerves, or on the face or genital area. The surgeon removes the cancer, followed by a thin layer of surrounding skin, which is examined under a microscope for cancer cells. If cancer cells are still present, the surgeon removes another layer. This process continues until no cancer cells are detected.
Cryosurgery involves freezing the skin cancer so that it eventually falls off. This may be recommended if the cancer isn’t deep and/or the patient isn't a candidate for more invasive surgery due to underlying health conditions.
Radiation therapy, which uses X-ray energy to kill cancer cells and shrink tumors, may be an option if the cancer is difficult to remove via surgery or the patient isn't a candidate for surgery. Several radiation treatments will likely be needed to treat the cancer.
With photodynamic therapy, the doctor first applies a light-sensitizing topical to the area. Then a laser or light-based device is used to activate the topical agent, with the aim of destroying malignant cells and sparing healthy tissue when possible. PDT can help treat some superficial squamous cell carcinomas on the face and scalp.
Two topical medications, 5-fluorouracil (5-FU) and imiquimod, can be applied directly onto the affected skin as treatment for superficial squamous cell carcinomas. Neither are approved specifically to treat squamous cell carcinoma, but they can be used off-label. Imiquimod stimulates the immune system to fight back against cancerous cells, while 5-FU kills tumor cells on or near the skin’s surface.
If spread is suspected, the care team may surgically remove nearby lymph nodes.
Once the tumor and/or lymph nodes are removed, the patient may need other treatments if the cancer continues to spread, including:
If the squamous cell carcinoma is advanced, especially if the cancer has started to spread into the space surrounding a nerve, radiation may be used after surgery or in combination with other treatments.
A newer type of cancer therapy, immunotherapy harnesses the power of the patient's immune system to recognize and destroy cancer. Libtayo® (cemiplimab) and Keytruda® (pembrolizumab) works by blocking PD-1, a checkpoint protein on the surface of T-cells in the immune system.
Targeted therapy, such as EGFR inhibitors, may help treat advanced squamous cell skin cancer, which can overexpress a protein called EGFR, helping fuel growth. Drugs targeting this protein can shrink some of these cancers. EGFR inhibitors may be used alone or in combination with other treatments for squamous cell carcinoma.
Chemotherapy drugs may be an option if the squamous cell skin cancer is spreading. Given intravenously once every few weeks, chemotherapy may slow the spread of the cancer and/or help relieve some symptoms. Sometimes chemotherapy can shrink tumors so that other therapies can be used to treat the cancer that remains.
If caught early, squamous cell carcinoma is highly treatable. While skin cancer is the most common cancer type among U.S. adults, cases are not required to be reported to cancer registries, so exact incidence breakdowns of types like squamous cell carcinoma are not known.
One way people with cancer estimate life expectancy is to evaluate the five-year relative survival rate for that cancer type. This percentage shows the likelihood that a person with a specific type and stage of cancer may live for at least five years after the diagnosis, compared with people who don't have cancer.
According to numbers tracked by the Canadian Cancer Society, the five-year relative survival rate for squamous cell carcinoma is 95 percent.