8 things to know about squamous cell and basal cell carcinoma (skin cancer)

More than 2 million Americans will learn they have some form of skin cancer this year. It’s the most frequently diagnosed type of cancer in the United States. It’s also one of the most preventable.

So, what causes skin cancer, and what can you do to reduce your risk of developing it?

We spoke with dermatologist Anisha Patel, M.D., to learn more. Here’s what she had to say.

What are the most common types of skin cancer?

The most common type of skin cancer — and the most common type of cancer, period — is basal cell carcinoma. More people are diagnosed with skin cancer each year than with any other kind of cancer.

The second most common skin cancer is squamous cell carcinoma. That’s a cancer of the epithelial lining, though, so it can occur in other places, too, such as the lungs and gut. But squamous cell carcinoma of the skin is usually UV-exposure related.

Melanoma is a distant third, making up only 3% of skin cancer diagnoses each year. But it often gets more attention because it can be so aggressive.

Other types of skin cancer are seen with far less frequency.

How do basal cell and squamous cell carcinomas differ from melanoma? What distinguishes them?

Melanoma develops from melanocytes, which are the pigment-producing cells that give our skin its color. They’re normally found in the top layer of the skin, near the base. Melanoma is usually pigmented, like a freckle, whereas other skin cancers are typically not.

Basal and squamous cell carcinomas, meanwhile, are cancers of the very top layer of skin, so often there’s a noticeable change in texture. Someone might notice a rough or scaly patch. In the early, precancerous stages, people often mistake this for dry skin. But once it progresses to cancer, it doesn’t look like dry skin anymore.

How are basal cell carcinoma and squamous cell carcinoma typically diagnosed?

Often, patients will come in with a new growth or a lesion that appears spontaneously and won’t heal. Other times, people will say that one of their parents had skin cancer, and this growth looks like theirs did.

Sometimes, even a friend’s or a colleague’s diagnosis will make people scrutinize their skin a little more closely. But once someone has been diagnosed with skin cancer, they see a dermatologist for screening regularly, so we’re able to catch any additional skin cancers much earlier.

Why is it important to get skin cancer treated as early as possible?

A lot of people have this idea that basal and squamous cell skin cancers don’t metastasize. And that’s not true. They don’t spread with the same frequency as melanoma, but they can still spread and cause problems when they occur close to the eyes, nose or ears. They can also invade nerves and bone tissue, so there’s a definite benefit to finding and treating them early.

What types of skin cancer treatments are available for basal cell and squamous cell carcinomas?

The standard of care for most skin cancer is excision, or surgical removal of the growth under local anesthesia. It’s done on an outpatient basis in the clinic, so patients don’t have to be admitted to the hospital.

Another option for low-risk cancers is called electrodessication and curettage. That’s where doctors take a surgical tool called a curette and physically scrape the tumor out. Then they use a form of cauterization to burn the base that’s left.

Often, these cancers are superficial, so surgeons can actually feel difference between the tumor and regular skin through the curette. This procedure has a low recurrence rate, and the recovery is very easy. A lot of our patients have bigger health problems to focus on — including other types of cancer — so this is an effective and safe way to treat them while reducing the chances of infection.

In pre-cancerous lesions and thin skin cancers, we are using a chemotherapy cream called 5-FU or fluorouracil 5%, too — both to treat existing skin cancers and to prevent future recurrences.

What new treatment options are being explored for basal cell and squamous cell carcinomas?

We’re exploring targeted molecular therapies and immune checkpoint inhibitors. Cemiplimab, which falls in this second class of drugs, just got approved by the Food and Drug Administration for the treatment of squamous cell carcinoma. The main clinical trial for that drug was conducted here at MD Anderson.

There are also multiple drugs in the class of small molecule inhibitors that target the PTCH gene in basal cell carcinoma. We use it to shrink tumors before surgeons cut them out. And we use the same epidermal growth factor receptor (EGFR) inhibitors against squamous cell carcinoma that are used to treat lung and colon cancers.

We also have several clinical trials involving the same class of medications that includes cemiplimab. They’re being tested in both basal and squamous cell carcinomas. And they’re being delivered both by IV infusion and intra-lesionally, where the drug is injected directly into the tumor.

Why is it important for people with skin cancer to seek treatment at MD Anderson?

First, we have experienced doctors and entire teams dedicated to particular cancers. Second, we offer many different treatment options, including cutting-edge clinical trials, new drugs and more non-surgical interventions than other places do. And third, we are really good at looking at the whole picture, and doing what’s best for patients while considering their overall health.

If someone has bad diabetes, for instance, we might recommend treatments that reduce their risk of infection. And if someone has another type of cancer, we can suggest therapies that won’t interfere with their other treatments. I have literally done surgery on someone while they were being infused with chemotherapy, for that very reason.

What’s the one thing you want patients to know about skin cancer?

There are very few things we can control in life, but basal cell carcinoma, squamous cell carcinoma and melanoma have a known component of environmental exposure. Ultraviolet sun damage is clearly linked to these tumors, so prevention really is THE most important thing. That means using sunscreen regularly, wearing protective clothing when outdoors, and staying out of the sun between 10 a.m. and 4 p.m., when the UV rays are the strongest.

Unlike smokers, who can undo some of the lung damage after a certain number of years of not smoking, you can’t undo skin damage received during your teens or 20s. It’s cumulative. So, the more you focus on prevention early on, the better off you are.

Anisha Patel, M.D., is a dermatologist at MD Anderson.

Request an appointment at MD Anderson online or by calling 1-877-632-6789.