A squamous cell carcinoma (SCC) begins in the thin, flat cells that make up the outermost layers of the skin. In addition to basal cell carcinoma, SCC occurs in other parts of the body, such as the mouth, throat, lungs, and genitals. SCC is the second most common form of skin cancer after basal cell carcinoma.
Sunlight or artificial sources of ultraviolet (UV) radiation, such as tanning beds or lamps, are the main causes of SCC. Squamous cells are damaged by UV radiation, which leads to abnormal growth and tumor formation. Other factors that can increase the risk include:
Having fair skin, light eyes, and blond or red hair.
Being older than 65 years.
Having a history of sunburns, especially at a young age.
Having a weakened immune system or taking medications that suppress the immune system, such as organ transplant recipients.
Having a history of exposure to certain chemicals, such as arsenic, tar, or tobacco.
Having a history of human papillomavirus (HPV) infection, which can cause SCC in the genitals or anus.
Typically, SCC appears as a scaly, red, or crusty patch of skin that may bleed or itch. It can also look like a wart, sore, bump, or growth. SCC is usually found in the following places:
The scalp, ears, lips, or nose, which are often exposed to the sun.
The arms, legs, chest, or back, which may also receive sun exposure.
The mouth, tongue, throat, or esophagus, which may be affected by smoking, alcohol, or HPV.
The genitals or anus, which may be affected by HPV or other sexually transmitted infections.
SCC is diagnosed by a healthcare provider who examines the skin and asks about its history and symptoms. The biopsy process involves removing a small sample of tissue and sending it to the laboratory for testing if it is suspected of SCC. The biopsy can confirm the diagnosis and determine the type and stage of the tumor. Stages of SCC indicate how deep the tumor has grown into the skin and whether it has spread to other parts of the body.
Stage 0: The tumor is only in the top layer of the skin and has not invaded the deeper layers. This is also called in situ SCC or Bowen’s disease.
Stage I: The tumor is less than 2 centimeters (cm) in diameter and has not spread to the lymph nodes or other organs.
Stage II: The tumor is larger than 2 cm in diameter or has invaded the deeper layers of the skin, but has not spread to the lymph nodes or other organs.
Stage III: The tumor has spread to one or more nearby lymph nodes, but not to other organs.
Stage IV: The tumor has spread to other organs, such as the lungs, liver, or bones.
It depends on the location, size, type, and stage of the tumor, as well as the patient's overall health and preferences how the tumor is treated. It is important to remove or destroy the tumor in order to prevent it from spreading or recurring. The following are some of the treatment options for SCC:
Surgical procedures can be performed with scalpels, curettes, or lasers to remove the tumor and surrounding healthy tissue completely. After surgery, a skin graft or flap may be used to cover the wound.
A mohs operation involves removing the tumor layers at a time and then examining them under a microscope until no cancer cells are found. Mohs surgery is a method for removing the entire tumor without damaging the surrounding healthy tissue. It is commonly used for large, recurrent, or cosmetically sensitive tumors, such as those on the face.
Small or superficial SCCs can be treated using cryosurgery, which involves freezing the tumor with liquid nitrogen.
SCCs that are small and superficial are often treated with electrodessication and curettage, which involves scraping off the tumor and then using an electric needle to destroy any remaining cancer cells.
Cancer cells are killed or stopped from growing using radiation therapy, which uses high-energy rays or particles. By placing radioactive materials near the tumor, radiation therapy can be given externally, or by a machine directing the radiation to the tumor. It can also be used as an adjuvant treatment after surgery to reduce the risk of recurrence in SCCs that are hard to remove by surgery.
Using drugs to kill cancer cells or stop them from growing is known as chemotherapy. It can be administered systemically, by way of an injection or cream, or topically by way of a lotion or cream. In addition to treating SCCs that have spread to other parts of the body, chemotherapy can also be used as an adjuvant to surgery or radiation to reduce the risk of recurrence after surgery or radiation therapy.
A drug that stimulates the immune system to fight cancer cells is called immunotherapy. It can be given systemically, through injection, or topically, by applying a cream or lotion to the skin. In addition to treating SCCs that have spread to other parts of the body, immunotherapy can also be used as an adjuvant treatment after surgery or radiation therapy to prevent recurrence.
Drugs that target specific molecules or pathways involved in the growth and survival of cancer cells are used in targeted therapy. They can be given systemically, or by injection. As an adjuvant therapy after surgery or radiation therapy to reduce the risk of recurrence, targeted therapy can be used as a main treatment for SCCs that have spread to other parts of the body.
The best way to prevent SCC is to protect the skin from UV radiation, which is the main cause of the disease. Some of the preventive measures include:
Avoiding or limiting sun exposure, especially between 10 a.m. and 4 p.m., when the sun’s rays are the strongest.
Wearing protective clothing, such as hats, sunglasses, long sleeves, and pants, when outdoors.
Applying sunscreen with a sun protection factor (SPF) of at least 15, and reapplying it every two hours or after swimming or sweating.
Avoiding tanning beds or lamps, which emit UV radiation that can damage the skin and increase the risk of SCC.
Checking the skin regularly for any changes or signs of SCC, and reporting them to a healthcare provider as soon as possible.
Seeking medical attention for any chronic or non-healing wounds, sores, or infections on the skin, which may be precursors of SCC.
Quitting smoking, which can increase the risk of SCC in the mouth, throat, or lungs.
Getting vaccinated against HPV, which can cause SCC in the genitals or anus.
Based on the location, size, type, and stage of the tumor, as well as the treatment received and response to treatment, SCC has a good prognosis if it is detected and treated early, before it spreads to other parts of the body. About 95% of people who have SCC that is only in the skin survive five years. About 50% of people with SCC that has spread to the lymph nodes survive five years. The five-year survival rate for SCC that has spread to other organs is about 15%.
