What is squamous cell carcinoma?
Squamous cell carcinoma is a type of skin cancer that begins in the squamous cells, which are the thin, flat cells that make up the outer layer of skin. Squamous cell carcinomas are one of the most common types of skin cancers. They can develop anywhere on the body but are most often found on areas frequently exposed to the sun, such as the face, ears, neck, lips, and backs of the hands. Squamous cell carcinomas tend to grow and spread slowly. While they are not as dangerous as melanoma, the deadliest form of skin cancer, squamous cell carcinomas can become life-threatening if not treated.
What causes squamous cell carcinoma?
Most cases of squamous cell carcinoma are caused by cumulative, long-term exposure to ultraviolet (UV) radiation from sunlight or tanning beds. The risk increases as a person gets older. People with fair skin, blonde or red hair, and light-colored eyes are at greater risk because they have less melanin, the pigment that helps protect skin from UV damage. A suppressed immune system and HPV (human papillomavirus) infection are also risk factors for developing squamous cell carcinomas. Rare genetic syndromes such as albinism and xeroderma pigmentosum put people at higher risk as well.
What are the symptoms of squamous cell carcinoma?
Squamous cell carcinomas often first appear as scaly red patches, open sores, elevated growths with a central depression, or warts that may crust or bleed. They commonly form on sun-exposed areas of the body but can occur anywhere. Symptoms may include:
- A firm, red nodule or bump
- A flat lesion with a scaly, crusted surface
- A rough, scaly patch that may crust or bleed
- A sore that doesn’t heal
- A raised growth with a depression in the center
- A rapidly growing wart
Squamous cell carcinomas may be tender to the touch or painful, but they are usually not itchy. See your dermatologist right away if you notice any unusual skin changes or growths. Early detection offers the best chance for effective treatment.
When to see a doctor
You should make an appointment with your dermatologist if you notice any of the following:
- A new growth or sore that does not go away within several weeks
- A spot or sore that continues to itch, hurt, crust, scab, or bleed
- An open sore that does not heal
- A firm, red lump that bleeds or looks ulcerated
- A rough, scaly patch on your skin or lip that grows slowly
See your doctor even if you are unsure about a mark on your skin. It’s important to get checked out to determine if it might be cancerous. Catching squamous cell carcinoma early is key for effective treatment.
Who is at risk for squamous cell carcinoma?
While anyone can get squamous cell carcinoma, the following factors increase your risk:
- Fair skin. Having less melanin (pigment), which provides some sun protection, puts you at higher risk. People with blond or red hair; light-colored eyes; freckles; and skin that always burns, never tans are more vulnerable.
- A history of sunburns. Getting severe sunburns, especially in childhood, raises your lifetime risk of squamous cell carcinoma.
- Older age. The risk of squamous cell carcinoma increases as you get older. Most cases occur in people over age 50.
- A personal history of skin cancer. If you’ve had melanoma or another form of skin cancer, you have a higher risk of developing squamous cell carcinoma.
- HPV infection. Some strains of human papillomavirus (HPV), a sexually transmitted infection, raise squamous cell carcinoma risk.
- A weakened immune system. People whose immune systems are suppressed due to certain medical conditions or medications are more prone to skin cancer.
- Exposure to chemicals. Arsenic, coal tar, paraffin, and certain oils used in metalworking may increase risk when exposed over time.
- Radiation exposure. People who have had radiation therapy for other cancers have a higher risk of squamous cell carcinomas.
- Genetic syndromes. Rare genetic disorders such as xeroderma pigmentosum result in extreme sensitivity to UV rays and increased skin cancer risk.
The more risk factors you have, the higher your chances of developing squamous cell carcinoma. Reducing sun exposure, avoiding tanning beds, and seeing your dermatologist regularly for skin checks can help lower your risk.
How is squamous cell carcinoma diagnosed?
To diagnose squamous cell carcinoma, your dermatologist will first examine your skin and the suspicious lesion. They will note the size, shape, color and other characteristics of the growth. If cancer is suspected, your doctor will remove all or part of the growth to have it examined under a microscope. This is called a biopsy.
There are a few types of biopsies used for suspected skin cancers:
- Shave biopsy: Using a thin, blade-like tool, the doctor shaves off the top layers of the growth.
- Punch biopsy: A deeper, circular piece of the growth is removed using a special instrument with a circular blade.
- Excisional biopsy: The entire growth is surgically removed and sent to the lab for testing.
A biopsy is the only definitive way to diagnose squamous cell carcinoma. A dermatopathologist will examine the biopsy sample under a microscope to determine if cancer is present. If it is cancerous, the biopsy report also provides information about the tumor that helps determine appropriate treatment.
What are the stages of squamous cell carcinoma?
Once squamous cell carcinoma is diagnosed, additional tests may be done to determine the stage of the cancer, which indicates how far it has progressed. This helps guide treatment options. Staging for squamous cell carcinomas considers the size of the tumor, whether it has grown deeply into skin/tissue, if it has spread to nearby lymph nodes, and whether it has metastasized (spread) to distant sites.
Stage 0: Abnormal cells are present in the outermost layer of skin. The cancer has not grown deeper. This stage is also called carcinoma in situ.
Stage I: The tumor is 2 centimeters (cm) across or smaller. It has not grown into deeper layers of skin or spread.
Stage II: The tumor is larger than 2 cm across but smaller than 4 cm and has not spread to nearby lymph nodes or other sites. It may be thicker with some invasion into lower layers of skin.
Stage III: The cancerous cells have spread to facial bones or 1 nearby lymph node but not to other organs. The tumor is larger than 4 cm across.
Stage IV: The tumor has grown into facial bones or multiple nearby lymph nodes. It may have spread to distant lymph nodes or organs such as the lungs.
Determining the stage of squamous cell carcinoma is important for choosing the most effective treatment. Low stage cancers have the best prognosis for being cured.
How is squamous cell carcinoma treated?
There are a variety of treatment options for squamous cell carcinoma based on the size and location of the tumor, whether it has spread, and other factors. Common treatments include:
- Surgery: Cutting out the tumor and surrounding tissue edges (wide local excision). Mohs surgery, which involves removing the visible tumor and microscopic traces, may sometimes be used for cancers on the head and neck.
- Curettage and electrodesiccation: Scrapping away cancer cells with a sharp tool and then killing remaining cells with an electric needle. Used for smaller, thin tumors.
- Cryosurgery: Freezing and destroying abnormal cells by applying liquid nitrogen. Often used to treat precancerous actinic keratoses.
- Radiation therapy: Using X-ray beams to kill cancer cells and shrink tumors. This may be done in combination with other treatments.
- Photodynamic therapy: Applying a light-sensitizing solution to cancer cells and then destroying them with a special laser light.
- Topical medications: Prescription creams containing anticancer agents that are applied directly to precancerous or cancerous skin growths.
- Systemic medications: Drugs such as cetuximab (Erbitux) that can boost the immune system and target cancer cells throughout the body.
The best approach depends on each case. Your treatment team will help determine the most suitable options based on your specific cancer, its stage and your overall health. Surgical excision is typically the standard treatment for most squamous cell carcinomas.
What is the prognosis for squamous cell carcinoma?
Most cases of squamous cell carcinoma are curable if caught and treated early. Treatment is highly successful for low stage cancers that have not spread to lymph nodes or other organs. The 5-year survival rate for localized squamous cell carcinomas is around 99%.
However, without treatment, squamous cell carcinomas can grow larger and penetrate deeper into tissues. They can destroy nearby tissue and bone and spread to other parts of the body, becoming much harder to cure. Advanced squamous cell carcinomas have a poorer prognosis, especially if the immune system is suppressed or the cancer spreads to lymph nodes or organs.
Regular self-exams and skin cancer screenings improve the likelihood of early detection and successful treatment. Any new, changing or unusual skin growths should be examined right away. Prompt treatment provides the best chance for a cure.
What happens if squamous cell carcinoma spreads?
Squamous cell carcinoma is considered metastatic, or stage IV, when it spreads (metastasizes) to lymph nodes or other organs beyond the original tumor site. The cancerous cells can break away and travel through the lymph vessels or bloodstream to distant parts of the body.
Common sites where squamous cell carcinoma may spread include:
- Nearby lymph nodes
- Lungs
- Bones
- Liver
When squamous cell carcinoma metastasizes, it becomes much more serious and life-threatening. At this point, it is very difficult to cure. Treatments focus on trying to shrink tumors, relieve symptoms, and prolong life. Options may include:
- Surgery to remove cancerous growths where possible
- Radiation therapy to shrink tumors and control symptoms
- Chemotherapy drugs that target cancer cells throughout the body
- Immunotherapy to boost the immune system to fight cancer
- Participating in clinical trials to access new investigative treatments
- Palliative care to maximize comfort and quality of life
The prognosis for metastatic squamous cell carcinoma varies considerably based on the location and extent of spread, as well as other factors like the patient’s overall health. On average, the 5-year survival rate for metastatic disease is around 35%. Catching and treating squamous cell carcinomas early before they have a chance to spread offers the best hope for survival.
Can squamous cell carcinoma be prevented?
While squamous cell carcinoma cannot always be prevented, you can significantly lower your risk by:
- Minimizing sun exposure, especially between 10am and 4pm when UV rays are strongest. Seek shade.
- Wearing protective clothing such as wide-brimmed hats, long-sleeved shirts and pants when out in the sun.
- Applying broad spectrum, water-resistant sunscreen with an SPF of 30 or higher to all exposed skin.
- Avoiding tanning beds and sunlamps, which emit concentrated UV radiation.
- Getting annual skin exams by a board-certified dermatologist.
- Examining your skin monthly and being aware of any changes or new growths.
- Treating precancerous skin lesions like actinic keratoses early before they become cancerous.
- Avoiding tanning and UV tanning booths.
- Quitting smoking. Tobacco use raises squamous cell carcinoma risk.
While you cannot always prevent squamous cell carcinomas completely, early detection and treatment provide the best odds for survival. Check your skin often and see your dermatologist once a year. Report any suspicious lesions immediately.
Conclusion
Squamous cell carcinoma is a common type of skin cancer that can usually be cured with early treatment. While not as aggressive as melanoma, squamous cell carcinoma should not be ignored, as it can be disfiguring or even life-threatening if allowed to grow. Anyone can get squamous cell carcinoma, but your risks increase with age, sun exposure, fair skin, weakened immunity and certain genetic disorders. Checking your skin monthly and seeing a dermatologist annually improves the chances of catching squamous cell carcinomas early when they are most treatable. Prompt treatment for suspicious lesions provides the best opportunity for a cure. While worrying is normal when faced with any cancer diagnosis, keep a positive attitude and follow your doctor’s recommendations for care. With early detection and proper treatment, most people with squamous cell carcinoma can be cured.