Squamous cell carcinoma

Squamous cell carcinoma is a type of skin cancer that grows from squamous cells, which are flat cells found in the outer layer of the skin. It typically develops as a red, scaly patch or a sore that fails to heal, and it can occur on sun-exposed areas of the body. Squamous cell carcinoma can affect the surface lining of certain parts of the body like the head and neck and genitals. If left untreated, it can grow and spread to other parts of the body.

Squamous cell carcinoma is the second most common type of skin cancer in the United States, after basal cell carcinoma. It also makes up about 90 percent of all head and neck cancers. Early detection and treatment are essential for the best outcomes.

Penn Medicine is home to many of the most experienced specialists that work together to diagnose, treat, and research the full range of skin cancers, to provide our patients with better outcomes and quality of life after a skin cancer diagnosis. Our unique approach gives you access to the latest and most advanced treatments and surgical methods, with opportunities to participate in clinical trials when available. 

Squamous cell carcinoma can develop in different forms depending on its location and characteristics.

• Squamous cell carcinoma of the skin: The most common type, it typically occurs in the outermost part of the epidermis on sun-exposed areas of the skin such as the face, ears, neck, hands, and arms. 
• Squamous cell carcinoma of the head and neck: It occurs in certain tissues within the head and neck region, including the throat, mouth, sinuses, and nose. 
• Squamous cell carcinoma of the genitals: It develops in the lining of the vagina, vulva, cervix, and penis, and is usually associated with HPV. Most genital cancers are squamous cell carcinomas.

Squamous cell carcinoma signs and symptoms can vary but may include:

• Skin changes like a red, scaly patch or a sore that may crust or bleed 
• Changes in existing moles, growths, or freckles 
• Raised or thickened skin that feels different from the surrounding skin 
• Sore throat, difficulty swallowing, earache, or voice changes 
• A lump in the throat, mouth, or neck 
• Numbness, tingling, or itching on the lips, mouth, or genitals 
• Growths or tumors on or near the genitals 
• Sores or foul odor in the genitals

It’s important to note that not all skin changes or sores are cancerous. However, any concerning or persistent symptoms should be evaluated by your doctor. Early detection and treatment of squamous cell carcinoma cancer can significantly improve outcomes. 

Squamous cell carcinoma skin cancer is often caused by prolonged exposure to ultraviolet (UV) radiation from sunlight or tanning beds. UV radiation damages the DNA in skin cells, causing mutations that can trigger the development of cancerous growths. Other risk factors include fair skin, a history of sunburn, increasing age, chronic skin inflammation, exposure to certain chemicals, and a history of skin cancer.

There are additional factors that contribute to skin cancer on areas of the body that aren’t typically exposed to the sun. For example, a weakened immune system, tobacco or alcohol use, and human papillomavirus (HPV) can lead to squamous cell carcinoma. 

Staging is a way to make sure you get the right treatment for squamous cell carcinoma. Our doctors use the TNM system, one of the most widely used cancer-staging systems worldwide. It describes:

• Tumor (T): The size and other characteristics of the main tumor, called the primary tumor. 
• Node (N): The number of lymph nodes affected by cancer cells. 
• Metastasis (M): If the cancer has spread to other parts of the body.

These details help to classify the cancer into stages:

• Stage 0: Also referred to as squamous cell carcinoma in situ, the cancer hasn’t spread from the outer layer of the skin, called the epidermis. 
• Stage I: The tumor is small and limited to the epidermis and middle layers of the skin, called the dermis. 
• Stage II: The tumor has affected the deeper layers of skin, called the subcutis, and the nerves. 
• Stage III: The tumor has affected underlying tissues or structures such as nearby lymph nodes. 
• Stage IV: The cancer has spread to distant lymph nodes or distant organs such as the lungs, liver, or brain.

Some types of squamous cell carcinoma can be prevented. Reduce your risk of this cancer type by following proper precautions:

• Avoid peak sun exposure: During peak sun hours (10 am to 4 pm), find shade and wear protective clothing like wide-brimmed hats, long sleeves, and UV-blocking sunglasses. 
• Use sunscreen daily: Apply broad-spectrum SPF 30+ sunscreen to exposed skin (including face, neck, ears, hands, and lips) every two hours, or more often if sweating or swimming. 
• Do not use tanning beds: Indoor tanning emits harmful UV rays that increase skin cancer risk. There’s no safe indoor tan. 
• Perform regular skin examinations: Regularly check for new or changing moles, freckles, or lesions. Schedule skin exams with your dermatologist. 
• Do not smoke: Smoking not only harms your lungs but also increases the risk of squamous cell carcinoma, especially in the mouth and lips. Quitting benefits your overall health. 
• Manage chronic conditions: If you have chronic skin conditions, like actinic keratosis, or a weakened immune system, work with your doctor to manage them and lower your cancer risk. 
• Protect yourself from HPV: Get the HPV vaccine, practice safe sex with condoms, and maintain regular checkups with your doctor.

By incorporating these preventive measures into your routine, you can significantly reduce your risk of developing squamous cell carcinoma and other skin cancers.