Next to basal cell carcinoma, squamous cell carcinoma (SCC) is the second-most common type of skin cancer, with 1.8 million cases diagnosed each year in the US. A type of non-melanoma skin cancer, SCC frequently begins as a precancerous lesion called actinic keratosis (AK).
Actinic keratosis is very common, affecting an estimated 58 million Americans. AK is considered to be the most common type of precancerous skin lesion, as most cases of SCC begin as AK lesions. However, not all AK lesions will become cancerous. In this article, we break down the differences between actinic keratosis and squamous cell carcinoma and what to look for when checking your skin at home.
What Is Actinic Keratosis?
Also called solar keratosis, actinic keratosis is a rough, scaly patch or bump on the skin caused by exposure to UV light. While anyone can get AK, those with fair skin and light hair and eyes tend to be more susceptible. AK also tends to be more common in men and women over the age of 40, though it can appear at any age. The most common areas for AK lesions to form are areas that are often exposed to the sun, such as the face, ears, neck, chest, forearms, and backs of the hands.
An estimated five to ten percent of AK lesions will become cancerous — most frequently, squamous cell carcinoma. However, it can be difficult or, in some cases, impossible to clinically distinguish AK from SCC. Therefore, it is crucial to keep a close eye on all skin lesions to detect any early signs that they could become cancerous.
Some common signs of actinic keratosis on the skin include:
- Rough, scaly patch of skin, usually less than one inch in diameter
- Slightly raised bump on the skin
- Irregular borders
- Variations in color, ranging from flesh-colored to pink to brown
- Some may itch, bleed, crust, or be painful to the touch
What Is Squamous Cell Carcinoma?
Squamous cell carcinoma is a type of non-melanoma skin cancer that affects the squamous cells, located near the surface of the epidermis. Squamous cells have a thin, scale-like appearance and aid in the protective barrier function of the skin. Healthy squamous cells are continuously shed and replaced by new ones. When exposed to UV light, squamous cells have the potential to sustain DNA damage, causing abnormal growth. This is what causes squamous cell carcinoma.
Like actinic keratosis, SCC most frequently occurs on sun-exposed areas of the face and body and often resembles a scaly, red patch or bump on the skin. These similarities make the two conditions difficult to differentiate. For this reason, it is imperative to perform regular self-exams and maintain annual skin cancer screenings with your dermatologist. While SCC is rarely fatal, it can spread to other areas of the body and become dangerous if left untreated.
Some common signs of squamous cell carcinoma include:
- Rough, scaly, or crusty patches of skin
- Persistent wart-like growths
- Red, inflamed patches of skin that resemble a rash
- Raised bumps or nodules
- Open sores or ulcers that may bleed or ooze
- Tender or painful to the touch
- Irregular borders
- Variations or changes in color, size, or shape
Treatment Options
Because distinguishing between actinic keratosis and squamous cell carcinoma can be challenging through visual inspection alone, your dermatologist may conduct a biopsy to determine if cancerous cells are present. Biopsy results play a crucial role in accurately identifying AK or SCC, enabling your dermatologist to recommend the most effective treatment plan for your specific needs.
Treatment options for both AK and SCC can include various approaches. Cryotherapy, involving freezing the lesion with liquid nitrogen, is a common method. Laser therapy, utilizing focused light to remove or destroy abnormal cells, is another effective option. Surgical excision involves physically removing the affected tissue, while curettage and electrodessication involves scraping off the lesion followed by the removal of residual cells via controlled electric current.
In some cases, less invasive treatments may be used. Topical medications can be applied to target and eliminate abnormal cells. Chemical peels involve applying a chemical solution to the skin’s surface, promoting exfoliation and the removal of damaged cells. Photodynamic therapy (PDT) uses a photosensitizing agent activated by light, selectively targeting and destroying abnormal cells.
Choosing the most suitable treatment depends on factors like the size, location, and extent of the lesions, as well as considerations based on your unique needs and preferences. A collaborative discussion with your dermatologist ensures a personalized and effective approach to managing and treating actinic keratosis and squamous cell carcinoma.
Can AKs and SCCs Be Prevented?
The single-best way to prevent actinic keratosis and squamous cell carcinoma is to practice good sun safety habits. These include:
- Wearing SPF 15 or higher on a daily basis.
- Wearing sun-protective clothing when outdoors for long periods of time.
- Seeking shade during peak sunlight hours of 10 a.m. to 4 p.m.
- Avoiding tanning beds and deliberate outdoor tanning.
Additionally, because actinic keratosis and squamous cell carcinoma can be challenging to differentiate, and because both can resemble other skin problems like warts or rashes, it is crucial to keep up with regular skin exams from your dermatologist. As with other types of skin cancer, early intervention of squamous cell carcinoma can minimize the risk of its spreading to deeper layers of skin or other areas of the body.
Bottom Line
Actinic keratosis and squamous cell carcinoma often appear similar and can be difficult to tell apart. However, knowing the general signs of each condition to look for can help you to spot early signs of either condition and then get your dermatologist involved as soon as possible. While SCC is rarely life-threatening, early treatment is crucial to avoid its continued growth and further complications.
If you think you have noticed signs of either actinic keratosis or squamous cell carcinoma on your skin, please call our Delray Beach office at 561-498-4407 or contact us online to schedule an appointment for a skin exam with one of our skin cancer experts.
