Squamous Cell Carcinoma
What Is a Squamous Cell Carcinoma?
Squamous cell carcinomas (SCC) are the second most common type of skin cancer, after basal cell carcinomas. When in its earliest stages, this type of lesion typically develops in the outer skin layer, known as the epidermis, and is referred to as squamous cell carcinoma in situ (or Bowen’s disease). If left untreated, a squamous cell carcinoma can spread to the deeper skin layers, at which point it is called invasive SCC.
What Are the Symptoms of Squamous Cell Carcinomas?
Squamous cell carcinomas tend to present on areas frequently exposed to the sun—such as the face (especially on the eyelids, nostrils, and ears), back of the hands, and lower arms. These skin tumors usually look like scaly patches of skin that will not seem to heal. Squamous cell carcinomas can also bleed easily, itch, and feel tender, but in most cases, they cause little to no discomfort.
Many patients develop a squamous cell carcinoma in the area of an actinic keratosis (AK), which is a precancerous lesion that typically looks red, scaly, and elevated. While an actinic keratosis is not malignant, the abnormal skin cells can progress into a squamous cell carcinoma if left untreated.
Am I at Risk of Squamous Cell Carcinomas?
As with any skin cancer, excess sun exposure is one of the biggest risk factors of squamous cell carcinomas. Men and women who are more vulnerable to this type of tumor include those who use tanning beds, work jobs outside, and have outdoor hobbies. In addition, those at a higher risk of developing squamous cell carcinomas tend to exhibit the following characteristics:
- Fair complexion and light-colored eyes
- Skin that burns easily instead of tanning
- Excessive sun exposure
- Exposure to arsenic and certain other chemicals
- Previous treatments with radiation and X-rays
- Family history of SCC
How Fast Do Squamous Cell Carcinomas Spread?
Squamous cell carcinomas typically spread slowly, and they have a low rate of metastasis (spreading to other parts of the body). When caught in its early stages, a squamous cell carcinoma is highly curable, but approximately 2-6% of squamous cell carcinomas metastasize. Most of the time, these lesions only break down the skin and tissues where they have developed. However, if a squamous cell carcinoma presents in a high-risk location—such as on the lips, ears, genital region, or within a scar—or has the chance to grow significantly larger and deeper, this can increase the chance of spreading. Those with suppressed immune systems are also at an increased risk of having their skin cancer spread.
How Is a Squamous Cell Carcinoma Diagnosed?
To diagnose a squamous cell carcinoma, our board-certified dermatologist, Dr. Adam Mamelak, will recommend a biopsy of the area to examine the skin cells under a microscope. If squamous cells are present, he will recommend the most conservtive form of treatment that can effectively address your skin tumor.
Since these lesions are often associated with little to no discomfort, it is important for you to be aware of any changes to your skin appearance, scheduling an appointment with your dermatologist if you notice any irregularities. Scheduling routine skin exams once per year is also recommended to allow your dermatologist to detect any changes with existing growths or discover new lesions that need further evaluation.
How Are Squamous Cell Carcinomas Treated?
The optimal treatment method for your squamous cell carcinoma will depend upon its location, size, and depth. Common techniques include topical creams, light therapy, and surgical excision.
Topical treatments for squamous cell carcinomas may include 5-Fluorouracil (a chemotherapy cream) or imiquimod (an immune response modifying cream). If prescribed, these treatments are typically continued for a few weeks, which allow the active ingredients to destroy the damaged skin cells.
Photodynamic Therapy (PDT) is a light-based treatment that involves placing a chemical on the affected area and exposing it to the specialized light. This process activates the chemical, which destroys the squamous cells.
Liquid nitrogen is carefully applied to the squamous cell carcinoma, which works by freezing the lesion and destroying the cancerous cells.
Curettage & Electrodesiccation
The tumor is removed using a curette tool, which scrapes the area. This is typically followed by the application of electric heat to cauterize the wound, known as electrodesiccation.
Mohs Micrographic Surgery
Many cases of squamous cell carcinoma are treated with Mohs micrographic surgery, due to its ability to remove the cancer with the most precise margins. Mohs has a cure rate of 99% and involves the use of a microscope to determine the extent of a squamous cell carcinoma and its roots. The affected cells are then surgically removed until the margins are clear.
For more information about squamous cell carcinomas and Mohs surgery, please contact Dr. Mamelak to schedule an appointment.