Squamous cell carcinoma is the second most common type of skin cancer after basal cell carcinoma. This cancer originates in the squamous cells of the skin, also known as keratinocytes. Squamous cell carcinoma affects about one million Americans every year.
Similar to basal cell carcinoma, this type of cancer is mostly found in fair-skinned people. Oftentimes people at risk have freckles or blue eyes and spend too much time in the sun.
Risks of Actinic Keratosis and Squamous Cell Carcinoma
One type of skin condition that isn’t cancerous but caused by overexposure to the sun is actinic keratosis. Actinic keratosis is rough, scaly patches on the skin. It’s caused by exposure to the sun for many years and appears on the face, neck, scalp, lips, or hands. These lesions grow slowly and are rarely seen in people younger than 40 years of age.
They are usually flat or slightly raised and less than 2.5 centimeters in diameter. These lesions can itch, burn, and bleed. The color varies from pink to red to brown. New lesions can occur over time on areas of the skin often exposed to the sun.
You should have precancerous skin lesions caused by overexposure to sunlight carefully evaluated. 5-10% of these lesions can turn into squamous cell carcinoma.
Symptoms of Squamous Cell Carcinoma
Squamous cell carcinoma can have various sizes, shapes, and appearances. They are often seen as thick scaly skin lesions with irregular borders and appearance. Unlike benign skin sores, it does not heal as the time goes by.
This form of skin cancer starts as a red patch covered with scales and crusts. As it grows, it starts to raise and becomes firmer. In some cases, it looks like a dome-shaped bump with a wart-like appearance. In other cases, it has raised edges and a depressed area in the center, which can bleed or itch. As the cancer progresses, the lesion can break open and grow deep into the skin tissue.
In many cases, squamous cell carcimona develops on areas of skin exposed to sunlight. However, it can also develop on mucous membranes of the eyes, nose, or genitals. If you have a history of genital warts, it’s a major risk factor for squamous cell carcinoma in the genital area.
Skin damaged by burns or with scars is susceptible to squamous cell carcinoma.
It’s also possible for this type of cancer to form in the mouth. There will be precancerous lesions that form first, though. There are two types of these lesions. If they are white, they’re leukoplakia. If they have a red color, they’re erythroplakia.
Types of Squamous Cell Carcinoma
Bown disease is a special type of squamous cell carcinoma. It can mimic psoriasis, eczema, or fungal infections. Patches that are flat, reddish-brown, with scales or crusts appear on the skin. Some people have one skin lesion while others have multiple patches. A skin biopsy can confirm the diagnosis.
Many doctors consider keratoacanthomas a subtype of squamous cell carcinoma. These lesions also develop in sun-exposed areas of the skin. They tend to grow quickly, reaching diameters of 2.5 centimeters or even more in just a couple of months. Some of them resolve spontaneously without any treatment, leaving a scar.
Identifying Cancerous Skin Lesions
Think ABCDE when looking at a skin lesion that may be cancerous.
A – asymmetry; if the lesion is an odd shape
B – borders that are irregular or notched
C – color; cancerous lesions tend ot have multiple or uneven colors and could change colors
D – diameter; if the size increases it could be cancerous
E – evolving; if the lesion changes in size, shape, color, or is itchy and bleeding see a doctor
If you notice a new lesion on your skin, check for these characteristics. It’s also important to keep an eye on the lesion to see if it changes.
Squamous Cell Carcinoma Treatment
Treatment of squamous cell carcinoma is similar to treating basal cell carcinoma. It may involve surgical excision, curettage, and electrodesiccation, chemotherapy applied topically, on the skin.
Cryosurgery involves freezing the spot with liquid nitrogen.
In this case, you’ll have a photosensitizing solution applied to the skin. A form of light then activates the solution. Doctors rarely use radiation therapy to treat squamous cell carcinoma.
Surgical excision is the treatment of choice if the cancer affects the lips or mucous membranes. Cases of cancer that spread beyond the skin to other organs may require radiation.
PD-1 inhibitor drugs like cemiplamab and pembrolizumab can help treat advanced cases. They are typically used when surgeons cannot remove the lesion.
Prognosis and Prevention
The overall prognosis is good for small lesions detected and treated early. The treatments currently available are effective and most people survive. Advanced cases that spread to the lymph nodes or distant organs can be fatal.
Growths larger than two centimeters or located near the ears, lips, or around nerves are likely to spread. Doctors keep the prognosis for this guarded.
Regular follow-up appointments with a dermatologist are essential. Compared with basal cell carcinoma, squamous cell carcinoma is more likely to spread to other organs if left untreated.
Remember to always wear sunscreen and keep sun exposure limited. Cover your skin when possible and be conscious of how much sun exposure you have.