CSCC in the Context of Skin Cancers and Risk Factors

Anna C. Pavlick, DO: Hello, and welcome to this CURE® Expert Connections® program: “Considering Immunotherapy for Cutaneous Squamous Cell Carcinoma.” I’m Dr. Anna Pavlick, the director of the Melanoma Research Program at NYU Langone Perlmutter Cancer Center in New York. Joining me for this discussion is Dr. Anthony Rossi, a dermatologic surgeon at Memorial Sloan Kettering Cancer Center in New York.

Today we are going to discuss immunotherapy, a novel treatment strategy that uses the body’s immune system to fight cancer. Specifically, we’ll be discussing how immunotherapy is being used to treat cutaneous squamous cell carcinoma: the second most common form of skin cancer.

The first topic we’re going to talk about is an overview of the squamous cell carcinoma of the skin. Dr. Rossi, how would you explain cutaneous squamous cell carcinoma [cSCC] to patients in the context of skin cancer?

Anthony Rossi, MD, FAAD: Hi, Dr. Pavlick. Thanks for having me. When I try to explain squamous cell carcinoma of the skin, I want to have the patient understand what type of skin cancer it is. We actually started to call squamous cell carcinoma keratinocyte carcinoma, to differentiate that from the old terminology, which was nonmelanoma skin cancer.

Squamous cell carcinoma is the second most common type of skin cancer of the skin, and it usually is associated in category with basal cell carcinoma, which is another type of keratinocyte carcinoma. We try to make this distinction because these 2 types of skin cancers come from epidermal or skin cells or the skin keratinocytes, and that differentiates it from other types of nonmelanoma skin cancer like Merkel cell carcinoma or adnexal carcinoma. So we like to make that distinction right off the bat.

Squamous cell now represents the second most common type of skin cancer: the first type is basal cell, the second type is cutaneous squamous cell carcinoma, and the third type is melanoma. We even go on further to make a distinction between squamous cell carcinoma that’s arising from the skin, the skin of the head and neck, or the skin of the body versus squamous cell carcinomas that arise from the mucosal surfaces like the inside of the mouth or the genital area because those also behave differently.

Anna C. Pavlick, DO: Are there any factors that put patients at risk for developing cutaneous squamous cell carcinoma?

Anthony Rossi, MD, FAAD: Sure. We know that squamous cell carcinoma of the skin is actually increasing in incidence. It’s actually increasing every year, and we know there are certain factors that predispose patients to getting this type of skin cancer. The No. 1 factor is UV [ultraviolet] radiation or exposure to the sun, so either artificial tanning or natural sunlight tanning is a risk factor because those with fair skin and light eyes and white hair are at already predisposed to getting this type of skin cancer. Though it’s the second most common type of skin cancer, there are about a million cases per year in the United States of squamous cell carcinoma of the cutaneous origin. That was in about 2018, and we know that most squamous cells do pretty well, but there will be a subset that either metastasize to the lymph nodes or have regional metastasis or even distant metastasis, so it does put the patient at risk for disease death or death due to disease.

Another factor that we know contributes to the risk of developing cutaneous squamous cell carcinoma besides UV radiation is immunosuppression. Whether they are immunosuppressed because of genetic reasons or from medications they’re taking to suppress their disease, or other immunosuppression from HIV/AIDS, or organ transplants, these patients are at higher risk we know for getting squamous cell carcinoma of the skin.

Anna C. Pavlick, DO: Again, if it’s not an underlying genetic thing, is there really anything that patients can do if they don’t have something intrinsic to really help reduce this risk?

Anthony Rossi, MD, FAAD: Definitely. We always advocate for our patients to use good sun protection and to not do artificial tanning or even natural sunlight tanning. Tanning just once actually increases your risk of getting not only a cutaneous squamous cell carcinoma but also melanoma, as we know. Just using really good sun protection—daily sunscreen with SPF 30 or above—is very helpful. Also, regular measures like wearing some protective clothing—hats, sunglasses, sun shirts—is really helpful if you’re going to be outside exercising or at the beach. It’s important to understand that there is no good way to get a tan and always use protection when you’re outdoors.

Anna C. Pavlick, DO: Great. I know it really has a lot to do with the rise of skin cancer that we’re seeing now. And I know also there have been a lot of campaigns trying to increase awareness. But we really need to make an impact on our young people and the children to start being much more aware, so that as they grow into adults, we’ll be able to see a decrease. I don’t know about you, but growing up we were always outside playing, we were always at the beach, and I don’t recall ever having sunscreen on because it just wasn’t something that was done. But now I see a lot more parents always putting sunscreen on their children, which makes me really happy.

Anthony Rossi, MD, FAAD: Definitely. Even for myself, growing up, I never wanted to put on sunscreen, but now I put it on religiously. It’s really helpful that we’re getting the campaigns out to the younger population, because really preventing these burns or this exposure earlier on can help prevent developing these skin cancers later on.

Transcript Edited for Clarity