Squamous cell carcinoma (SCC), a skin cancer

This article focuses solely on the treatments and stages of squamous cell carcinoma. For more general details on skin cancer, the risks and prevention, please consult Skin Cancer, an overview.

SCC of the skin is also known as cutaneous squamous cell carcinoma (cSCC). Adding the word “cutaneous” identifies it as a skin cancer and differentiates it from squamous cell cancers that can arise inside the body, in places like the mouth, throat or lungs. It is the second most common form of skin cancer, characterized by abnormal, accelerated growth of squamous cells. When caught early, most SCCs are curable.

One of three main types of cells in the top layer of the skin (the epidermis), squamous cells are flat cells located near the surface of the skin that shed continuously as new ones form.

SCC occurs when DNA damage from exposure to ultraviolet radiation or other damaging agents trigger abnormal changes in the squamous cells.

What does SCC look like?

SCCs can appear as scaly red patches, open sores, rough, thickened or wart-like skin, or raised growths with a central depression. At times, SCCs may crust over, itch or bleed. The lesions most commonly arise in sun-exposed areas of the body.

SCCs can also occur in other areas of the body, including the genitals.

The following stages are used for basal cell carcinoma and squamous cell carcinoma of the skin that is on the head or neck but not on the eyelid:

Stage 0 (Carcinoma in situ)

In stage 0, abnormal cells are found in the squamous cell or basal cell layer of the epidermis. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed and the tumor is 2 centimeters or smaller.

Stage II

In stage II, the tumor is larger than 2 centimeters but not larger than 4 centimeters.

Stage III

or

In stage III, one of the following is found:

• the tumor is larger than 4 centimeters, or cancer has spread to tissue covering the nerves below the dermis, or has spread below the subcutaneous tissue, or has spread to the bone and the bone has minor damage. Cancer may have also spread to one lymph node on the same side of the body as the tumor and the node is 3 centimeters or smaller, and cancer has not spread through to the outside covering of the lymph node; or
• the tumor is 4 centimeters or smaller. Cancer has spread to one lymph node on the same side of the body as the tumor and the node is 3 centimeters or smaller.

Stage IV

or

or

In stage IV, one of the following is found:

• the tumor is any size and cancer may have spread to the bone and the bone has minor damage, or to tissue covering the nerves below the dermis, or below the subcutaneous tissue. Cancer has spread to the lymph nodes as follows:
  • one lymph node on the same side of the body as the tumor, the affected node is 3 centimeters or smaller, and cancer has spread through to the outside covering of the lymph node; or
  • one lymph node on the same side of the body as the tumor, the affected node is larger than 3 centimeters but not larger than 6 centimeters, and cancer has not spread through to the outside covering of the lymph node; or
  • more than one lymph node on the same side of the body as the tumor, the affected nodes are 6 centimeters or smaller, and cancer has not spread through to the outside covering of the lymph nodes; or
  • one or more lymph nodes on the opposite side of the body as the tumor or on both sides of the body, the affected nodes are 6 centimeters or smaller, and cancer has not spread through to the outside covering of the lymph nodes.
• the tumor is any size and cancer may have spread to tissue covering the nerves below the dermis, or below the subcutaneous tissue, or to bone marrow or to bone, including the bottom of the skull. Also:
  • cancer has spread to one lymph node that is larger than 6 centimeters and cancer has not spread through to the outside covering of the lymph node; or
  • cancer has spread to one lymph node on the same side of the body as the tumor, the affected node is larger than 3 centimeters, and cancer has spread through to the outside covering of the lymph node; or
  • cancer has spread to one lymph node on the opposite side of the body as the tumor, the affected node is any size, and cancer has spread through to the outside covering of the lymph node; or
  • cancer has spread to more than one lymph node on one or both sides of the body and cancer has spread through to the outside covering of the lymph nodes.
• the tumor is any size and cancer has spread to bone marrow or to bone, including the bottom of the skull, and the bone has been damaged. Cancer may have also spread to the lymph nodes; or
• cancer has spread to other parts of the body, such as the lung.

The following stages are used for basal cell carcinoma and squamous cell carcinoma of the skin on the eyelid:

Stage 0 (Carcinoma in situ)

In stage 0, abnormal cells are found in the epidermis, usually in the basal cell layer. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Stage I

In stage I, cancer has formed. Stage I is divided into stages IA and IB.

• Stage IA: The tumor is 10 millimeters or smaller and may have spread to the edge of the eyelid where the lashes are, to the connective tissue in the eyelid, or to the full thickness of the eyelid.
• Stage IB: The tumor is larger than 10 millimeters but not larger than 20 millimeters and the tumor has not spread to the edge of the eyelid where the lashes are, or to the connective tissue in the eyelid.

Stage II

Stage II is divided into stages IIA and IIB.

• In stage IIA, one of the following is found:
  • the tumor is larger than 10 millimeters but not larger than 20 millimeters and has spread to the edge of the eyelid where the lashes are, to the connective tissue in the eyelid, or to the full thickness of the eyelid; or
  • the tumor is larger than 20 millimeters but not larger than 30 millimeters and may have spread to the edge of the eyelid where the lashes are, to the connective tissue in the eyelid, or to the full thickness of the eyelid.
• In stage IIB, the tumor may be any size and has spread to the eye, eye socket, sinuses, tear ducts, or brain, or to the tissues that support the eye.

Stage III

Stage III is divided into stages IIIA and IIIB.

• Stage IIIA: The tumor may be any size and may have spread to the edge of the eyelid where the lashes are, to the connective tissue in the eyelid, or to the full thickness of the eyelid, or to the eye, eye socket, sinuses, tear ducts, or brain, or to the tissues that support the eye. Cancer has spread to one lymph node on the same side of the body as the tumor and the node is 3 centimeters or smaller.
• Stage IIIB: The tumor may be any size and may have spread to the edge of the eyelid where the lashes are, to the connective tissue in the eyelid, or to the full thickness of the eyelid, or to the eye, eye socket, sinuses, tear ducts, or brain, or to the tissues that support the eye. Cancer has spread to lymph nodes as follows:
  • one lymph node on the same side of the body as the tumor and the node is larger than 3 centimeters; or
  • more than one lymph node on the opposite side of the body as the tumor or on both sides of the body.

Stage IV

In stage IV, the tumor has spread to other parts of the body, such as the lung or liver.

Treatment depends on the type of skin cancer or other skin condition diagnosed:

Squamous cell carcinoma occurs on areas of the skin that have been damaged by the sun, such as the ears, lower lip, and the back of the hands. Squamous cell carcinoma may also appear on areas of the skin that have been sunburned or exposed to chemicals or radiation. Often this cancer looks like a firm red bump. The tumor may feel scaly, bleed, or form a crust. Squamous cell tumors may spread to nearby lymph nodes. Squamous cell carcinoma that has not spread can usually be cured.

There are different types of treatment for patients with basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis.

Different types of treatment are available for patients with basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Eight types of standard treatment are used:

Surgery

One or more of the following surgical procedures may be used to treat basal cell carcinoma, squamous cell carcinoma of the skin, or actinic keratosis:

• Simple excision: The tumor, along with some of the normal tissue around it, is cut from the skin.
• Mohs micrographic surgery: The tumor is cut from the skin in thin layers. During the procedure, the edges of the tumor and each layer of tumor removed are viewed through a microscope to check for cancer cells. Layers continue to be removed until no more cancer cells are seen. This type of surgery removes as little normal tissue as possible. It is often used to remove skin cancer on the face, fingers, or genitals and skin cancer that does not have a clear border.

• Shave excision: The abnormal area is shaved off the surface of the skin with a small blade.
• Curettage and electrodesiccation: The tumor is cut from the skin with a curette (a sharp, spoon-shaped tool). A needle-shaped electrode is then used to treat the area with an electric current that stops the bleeding and destroys cancer cells that remain around the edge of the wound. The process may be repeated one to three times during the surgery to remove all of the cancer. This type of treatment is also called electrosurgery.
• Cryosurgery: A treatment that uses an instrument to freeze and destroy abnormal tissue, such as carcinoma in situ. This type of treatment is also called cryotherapy.

• Laser surgery: A surgical procedure that uses a laser beam (a narrow beam of intense light) as a knife to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
• Dermabrasion: Removal of the top layer of skin using a rotating wheel or small particles to rub away skin cells.

Simple excision, Mohs micrographic surgery, curettage and electrodesiccation, and cryosurgery are used to treat basal cell carcinoma and squamous cell carcinoma of the skin. Laser surgery is rarely used to treat basal cell carcinoma. Simple excision, shave excision, curettage and desiccation, dermabrasion, and laser surgery are used to treat actinic keratosis.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer.

External radiation therapy is used to treat basal cell carcinoma and squamous cell carcinoma of the skin.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing.

Chemotherapy for basal cell carcinoma, squamous cell carcinoma of the skin, and actinic keratosis is usually topical (applied to the skin in a cream or lotion). Topical fluorouracil (5-FU) is used to treat basal cell carcinoma.

Photodynamic therapy

Photodynamic therapy (PDT) is a cancer treatment that uses a drug and a certain type of light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein or put on the skin. The drug collects more in cancer cells than in normal cells. For skin cancer, laser light is shined onto the skin and the drug becomes active and kills the cancer cells. Photodynamic therapy causes little damage to healthy tissue.

Photodynamic therapy is also used to treat actinic keratoses.

Immunotherapy

Immunotherapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This type of cancer treatment is also called biotherapy or biologic therapy.

Interferon and imiquimod are immunotherapy drugs used to treat skin cancer.

• Interferon (by injection) may be used to treat squamous cell carcinoma of the skin.
• Topical imiquimod therapy (a cream applied to the skin) may be used to treat some basal cell carcinomas.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to attack cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do.

• Signal transduction inhibitors therapy: This treatment block signals that are passed from one molecule to another inside a cell. Blocking these signals may kill cancer cells. Vismodegib and sonidegib are signal transduction inhibitors used to treat basal cell carcinoma.

Chemical peel

A chemical peel is a procedure used to improve the way certain skin conditions look. A chemical solution is put on the skin to dissolve the top layers of skin cells. Chemical peels may be used to treat actinic keratosis. This type of treatment is also called chemabrasion and chemexfoliation.

Other drug therapy

Retinoids (drugs related to vitamin A) are sometimes used to treat squamous cell carcinoma of the skin. Diclofenac and ingenol are topical drugs used to treat actinic keratosis.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI website.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

If basal cell carcinoma and squamous cell carcinoma recur (come back), it is usually within 5 years of initial treatment. Talk to your doctor about how often you should have your skin checked for signs of cancer.

Treatment of Squamous Cell Carcinoma of the Skin

Treatment of squamous cell carcinoma that is localized may include the following:

• Simple excision.
• Mohs micrographic surgery.
• Radiation therapy.
• Curettage and electrodesiccation.
• Cryosurgery.
• Photodynamic therapy, for squamous cell carcinoma in situ (stage 0).

Treatment of squamous cell carcinoma that is metastatic or cannot be treated with local therapy may include the following:

• Chemotherapy.
• Retinoid therapy and immunotherapy (interferon).
• A clinical trial of a new treatment.

Treatment of recurrent squamous cell carcinoma that is not metastatic may include the following:

• Simple excision.
• Mohs micrographic surgery.
• Radiation therapy.