Squamous Cell Carcinoma Is Common
Squamous cell carcinoma is the second most common type of skin cancer. It commonly develops from a precursor lesion called actinic keratosis. However, it is less deadly than its better-known cousin, melanoma. Among the 3 main types of skin cancer, squamous cell carcinoma sits solidly in the middle in terms of incidence and mortality. Over 1 million cases of squamous cell carcinoma will be diagnosed in the U.S. this year. (1) This cancer can be locally destructive and rarely metastasizes.
Need to know only the basics about squamous cell carcinoma before going back to watching TV? Here are some quick stats and facts that you should know.
How is squamous cell carcinoma different from melanoma?
Squamous cell skin cancer is less malignant than melanoma. This type of cancer rarely metastasizes, similar to basal cell carcinoma. It originates from the squamous cells of the skin. The squamous cells are located in the upper part of the epidermis (the top layer of skin). Squamous cells look pink under the microscope after they are stained with Hematoxylin and Eosin. Under the microscope, this skin cancer has a characteristic appearance of keratin pearls interspersed throughout. They are called squamous cells because they are flat and elongated. They can form the epithelium of skin and other parts of the body like the inside of the urethra. On the other hand, melanoma originates from the melanocytic type of cell at the bottom of the epidermis. Melanomas are usually darkly pigmented skin lesions.
When you look at a squamous cell skin cancer with your eyes, you will typically see an ulcerated, scaly, red, patchy, and/or crusty lesion. It may bleed when scratched or even unprovoked. There can be a central depression that makes it look like an ulcer. Common locations are directly correlated with spots where there is more sun exposure. These include lower lips, ears, face, neck, scalp, hands, and extremities.
What are the risks factors for squamous cell carcinoma?
Do you have fair skin? Do you have light eyes or hair? Do you frequently expose yourself to the sun and for long periods of time? If you answered yes to any of the above questions, you need to watch out for all forms of skin cancer. (2) There are other certain high-risk groups that are more likely to develop squamous cell carcinoma. Smokers develop this type of skin cancer more often than non-smokers. People who have been exposed to radiation, chemicals, or PUVA treatment for psoriasis are also at increased risk. Make sure to provide your doctor with a complete medical and occupational history in order to gauge your risk.
There are other certain high-risk groups that are more likely to develop squamous cell carcinoma. Smokers develop this type of skin cancer more often than non-smokers. People who have been exposed to radiation, chemicals, or PUVA treatment for psoriasis are also at increased risk. Make sure to provide your doctor with a complete medical and occupational history in order to gauge your risk.
I’ve had an ulcerated skin lesion that hasn’t healed for a long time now. Should I see a doctor about this?
I can’t tell you whether your skin lesion is skin cancer or not. You should consult with your dermatologist anytime you are worried about something on your skin. They can check your skin lesion for any of the classic signs of squamous cell carcinoma. If you are worried about a new growth, you should show it to your dermatologist as soon as possible. The earlier the doctor is able to intervene and give you a definitive diagnosis the better. Early skin cancers are easier to treat than large, locally invasive cancers that have been growing for years.
Your dermatologist may use a special magnifying lens called a dermatoscope to decide whether your skin lesion looks suspicious or not. This is why it’s important to visit your dermatologist regularly and monitor your own lesions at home. Any changes can be signs of early skin cancer.
I made an appointment with my dermatologist. What should I expect?
Your doctor will listen to your history and take a look at the skin lesion. He or she will determine whether it is suspicious enough to warrant a biopsy. Since squamous cell skin cancers are usually ulcerated instead of nodular, the shave biopsy is not commonly used for this type of cancer. Squamous cell cancers are usually biopsied using a punch biopsy at the edge of the lesion. This tissue sample will include both normal and possibly cancerous skin. The pathologist will be able to determine what’s what under the microscope.
In order to begin any procedure, the doctor has to wipe the area with alcohol first. Then he or she will inject a local anesthetic such as lidocaine. The doctor will let the lidocaine take effect. This is almost immediate.
Next, he or she either removes the skin lesion entirely (as in a shave biopsy) or punches into the skin with a biopsy tool to get a full thickness skin sample. Depending on the type of biopsy, you may or may not need stitches.
In the case of the punch biopsy, the doctor will stick the punch biopsy tool into the skin and twist it to remove a piece of skin. That piece will be put into a biopsy bottle and sent to the pathologist. Bleeding from a shave biopsy can be controlled with a special solution such as aluminum chloride. Your dermatologist will dab this on to decrease the bleeding. A simple band-aid will usually suffice. Some dermatologists choose to place one stitch after a punch biopsy.
You will most likely experience some pain at the biopsy site, but this will be very minor. Over the counter pain killers such as acetaminophen or ibuprofen should be plenty.
You will then go home and recover from the procedure. Feel free to tell your loved ones it was a traumatic experience and demand that they bend to your will as you “recover.”
You can expect the pathologist to send a report to your dermatologist in 7-10 days with the results. If you haven’t gotten the results back from your doctor, call their office.
If I definitely have squamous cell carcinoma, how will my doctor treat it?
There are many options when treating squamous cell carcinoma. The option your doctor chooses will depend on the extent of invasion of your cancer, the size, the location on your body, and your preferences as a patient. (3,4) A small cancer will not require more than electrodesiccation and curettage or simple excision. A good dermatologist will always take the time to talk to you about possible complications and describe the procedure.
Here are the possible ways to treat squamous cell carcinoma:
Electrodesiccation and Curettage:
This is a fancy way of saying your doctor scrapes the skin cancer off and uses electricity to burn it. This can only be done on small cancers. The scraping is done with a curette tool. A curette is a metal tool with a sharp loop at the end. There will be 2-3 rounds of scraping and burning. The room will be saturated by the smell of burning human flesh, but if you can get through this very minor procedure you have a greater than 95% chance of being cured. You won’t need stitches, and the wound can be covered with a simple bandage.
Mohs Micrographic Surgery:
This method requires more time and labor for your dermatologic surgeon to complete. Not every dermatologist is also a Mohs surgeon, but all Mohs surgeons are also dermatologists. This is indicated when the cancer is located in a cosmetically sensitive area.
Mohs surgery has very high cure rates because the doctor is checking all the borders of the tumor to see if you are cured. You can read all about Mohs surgery here, or continue reading this page for a synopsis.
Steps in Mohs Surgery
Like most procedures, it begins with the injection of local anesthesia. The doctor will remove the skin cancer as close to the outwardly visible margins as possible. The site where the cancer was removed is covered and bleeding is minimized.
You head back to the waiting room until it’s your turn again. The doctor takes that sample that’s just been removed to a back room where a technician will prepare the sample to be seen under the microscope. The sample has been marked in a certain way so the orientation (up, down, left, or right) is known. When the sample is ready, the doctor will look at it under the microscope to see if the edges are clear of cancer.
If the margins are not clear, let’s say there is still a bit of cancer at the 9 o’clock position and the 5 o’clock position, then the dermatologic surgeon knows that he or she must cut further into those 2 sides. This goes on for as many rounds as necessary until you’re cured based on what is seen under the microscope.
Once you’re cured, the doctor decides on the best way to close the surgical site back up with the best possible cosmetic result. This will involve stitches. The stitches and the extent of the defect may look very big at first. Don’t be scared! Mohs surgery patients tend to heal well, and the scar is much smaller in a few months.
It’s called micrographic surgery because the greatest amount of healthy tissue is spared due to the fact that you’re using the microscope to check the sample every time.
This is the same procedure used to remove suspicious pigmented lesions that may be melanoma. The doctor applies anesthesia. Instead of cutting very close to the skin cancer, the doctor will cut with a margin of 2-3 millimeters in the shape of an ellipse. Then, the doctor closes the ellipse with stitches.
Simple excision is used when there isn’t a clear necessity for Mohs surgery. Why doesn’t my doctor go with Mohs every single time?Mohs surgery is expensive. Can you imagine how much more money it costs the healthcare system to check every piece of tissue removed? Plus the time the doctor has to spend going back and forth to check it. Seeing as we have limited healthcare resources, if you have a well-demarcated skin cancer on your leg. the dermatologist we can simply cut it off at a fraction of the cost and time. You do not want to be the patient in the waiting room for 5 rounds of Mohs.
The options for topical medications are imiquimod or 5-fluorouracil. These can be used for 3-6 weeks if the surface area of the cancer is large to reduce the size. These are only indicated for very superficial skin cancers. One major drawback is that since there is no removal of tissue, there is nothing to examine under the microscope by the pathologist. If the pathologist can’t examine the margins, you can’t be sure that you cured the skin cancer. These medicines can be irritating. This is the most common side effect that causes patients to stop the treatment.
Cryosurgery is the medical term for freezing something off with liquid nitrogen. This can be done with or without local anesthesia. The pain of the anesthesia is often worse than the liquid nitrogen. The doctor will spray liquid nitrogen about 3 times over the cancer spot. It will feel painful like a burn because it gets insanely cold. The skin will blister like a burn, and the skin will crust over and fall off. This is good for superficial basal cells. People with bleeding problems or intolerance to local anesthesia can be good candidates for cryosurgery. Cure rates aren’t as good compared to techniques that remove the skin cancer.
Radiation is only used when surgery is not an option. It may require 15-30 treatments. For elderly people or people in poor health, this may be their only option.
Photodynamic therapy, commonly referred to as PDT, is not commonly used for skin cancer. In this procedure, the doctor applies a photosensitizing agent like 5-aminolevulinic acid to the skin cancer.
A photosensitizing agent makes the cancer cells sensitive to light exposure. The cancer is then exposed to blue light. The cancer cells are selected by the medicine so only the cancer cells die. You can expect some redness and swelling. You have to avoid UV exposure for 2 days after this because the photosensitizing medicine may still be active.
This treatment is not FDA approved for squamous cell carcinoma but your doctor may use this off-label.
What did you learn about squamous cell skin cancer that you didn’t know before?
- Skin Cancer Foundation. Skin Cancer Facts & Statistics. http://www.skincancer.org/skin-cancer-information/skin-cancer-facts
- Skin Cancer Foundation. Squamous Cell Carcinoma – Causes and Risk Factors. http://www.skincancer.org/skin-cancer-information/squamous-cell-carcinoma/scc-causes-and-risk-factors
- Skin Cancer Foundation Squamous Cell Carcinoma Treatment Options. http://www.skincancer.org/skin-cancer-information/squamous-cell-carcinoma/scc-treatment-options
- American Academy of Dermatology. Squamous Cell Carcinoma. https://www.aad.org/dermatology-a-to-z/diseases-and-treatments/q—t/squamous-cell-carcinoma/diagnosis-treatment