How Serious Is a Squamous Cell Carcinoma?

I’d had a few skin cancers removed before, all basal cell carcinomas (BCCs), the most common type. But when I was diagnosed with a squamous cell carcinoma (SCC) on my scalp, it seemed different, and a little more scary. (You can read more about it in my story “A Hole in My Head.”) I asked C. William Hanke, MD, a Mohs surgeon at the Laser and Skin Surgery Center of Indiana and a senior vice president of The Skin Cancer Foundation, what we need to know about this second most common form of skin cancer.

Q: When people talk about nonmelanoma skin cancers, they tend to lump basal cell and squamous cell carcinomas together as the ones that are far less dangerous than melanoma. Should we take SCCs more seriously?

Dr. Hanke: Yes and no. BCCs hardly ever metastasize. I’ve seen two cases in my entire career. But when SCCs that haven’t been treated early get big, then the chance of metastasis becomes real. It’s uncommon, but it’s much more common than in BCC. We see it in our practice. But we don’t want to scare people into thinking that just because they have squamous cell, “Oh wow, I’ve got a chance of metastasis.” Remember, the rate is very low. It’s just those big ones.

Q: OK, so it’s rare. But what happens when an SCC does spread?

Dr. Hanke: The first place SCCs metastasize to is the regional lymph nodes. So if you have a squamous cell carcinoma on your cheek, for example, it would metastasize to the nodes in the neck. But there are treatments for that. Patients can have surgery, radiation and, in some advanced cases, immunotherapy medication. Cemiplimab (brand name Libtayo) is a checkpoint blockade therapy. The immune system has checkpoints that keep it from going out of control. Cancer cells can keep these checkpoints active, allowing the cancer to grow. Cemiplimab removes the shackles and allows your body’s T cells to hunt and kill SCC tumor cells. Approved by the FDA in 2018, this was the first immunotherapy treatment for patients with metastatic or locally advanced SCC that is not curable by surgery or radiation. In 2020, pembrolizumab (brand name Keytruda), another checkpoint blockade therapy, was approved for patients with recurrent or metastatic SCC that is not curable by surgery or radiation. In 2021, that approval was expanded to include patients with locally advanced disease.

Q: What’s the usual treatment for SCCs?

Dr. Hanke: There are a number of treatments for small and early SCCs, including freezing, scraping or excisional surgery. For other SCCs, your doctor may recommend Mohs surgery, which is done in stages and looks at all the edges of the tissue to make sure all the cancerous cells are removed. This lab work is done while the patient waits. The cure rate for SCCs that haven’t been treated previously is 99 percent. For an SCC that has recurred or is larger, the cure rate is a little lower.

Q: How can we detect SCCs as early as possible?

Dr. Hanke: Exposure to ultraviolet (UV) rays from the sun over time causes DNA damage in your skin cells that can lead to skin cancer. Sometimes precancerous lesions form called actinic keratoses, or AKs. At first they may be flat patches that feel scaly or crusty and don’t go away. They may develop into bumps or little “horns.” These can be easily treated a number of ways, including freezing, scraping, lasers and topical creams. That’s why it’s so important to see a dermatologist regularly and stop these before they become squamous cell carcinomas.