You may have heard that skin cancer is the most common form of cancer in the United States—and that there are a few different varieties. So, what are the different types of skin cancer, and how can you protect yourself?
Skin cancer can be categorized into two main groups: melanoma and nonmelanoma skin cancer (NMSC). The more common of these two categories is NMSC, including basal cell carcinoma and squamous cell carcinoma.
Across the board, chronic exposure to ultraviolet (UV) radiation is the leading cause of all types of skin cancers. This radiation causes DNA damage and leads to cell mutation. The damage builds up over time, resulting in cancer. Although skin cancer is most commonly found in sun-touched areas, such as the face, ears, scalp, arms, back, chest, and hands, it can occur almost anywhere on the skin.
Anatomy of the Skin
Skin cancers are generally differentiated by the types of cells they affect, so it's helpful to have a basic understanding of the layers of your skin.
The skin is made up of the epidermis, dermis, and hypodermis. The epidermis, the outer layer where most skin cancers form, is mainly composed of keratinocyte cells. The basal layer at the bottom of the epidermis is constantly making new skin that matures, forming the squamous epithelium that creates the skin barrier. Also located deep in the epidermis are melanocytes—cells that produce melanin, the pigmentation that gives our skin its color. The dermis, the middle layer of the main three, contains hair follicles, oil (sebaceous) glands, and nerves. The hypodermis mainly consists of fatty tissue.
Nonmelanoma Skin Cancers
The American Academy of Dermatology (AAD) estimates that approximately 9,500 people in the United States are diagnosed with skin cancer every day. So, if you're wondering what are the different types of skin cancer, you'll want to first recognize and understand the two leading types: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
Basal Cell Carcinoma
Most often found in light-skinned individuals, this type of cancer stems from mutation of the basal layer of the epidermis and gives rise to a tumor. As the most common form of skin cancer, it rarely metastasizes—spreads to other sites in the body—but if left long enough, it can cause local destruction of nerves and skin as well as disfiguring scars. For the majority of patients, BCC is a non-life-threatening cancer that is often indolent, meaning the individual may not notice it at all.
Squamous Cell Carcinoma
SCC, the second most common type, forms from squamous cells, which are found throughout the body, even internally. In the skin, they are near the surface, serving as a barrier to protect cells underneath. This cancer can develop anywhere there are squamous cells; however, the common places are the face, neck, and ears. SCC, for the most part, is also not life-threatening. However, this type is more aggressive than BCC and, if untreated for long enough, can metastasize elsewhere and ultimately become deadly.
Melanoma strikes when melanocytes are damaged over time, and mutate to form a tumor deep within the epidermis.
Melanoma accounts for the majority of skin cancer deaths and its incidence is on the rise, especially in young women. This may be due to increased tanning bed use. According to the AAD, 20 Americans die from melanoma each day, and it's projected to be the fifth most common cancer for both men and women. However, when caught early, the survival rate is 99 percent.
Although skin cancer is more commonly seen in fair-skinned individuals, it's important to recognize that skin cancer, including melanoma, can occur in any skin type. Genetics can play a role, but the majority of the risk factors for skin cancer are environmental: tanning (especially in tanning beds), chronic sun exposure, and intermittent sunburns. Most melanoma cases are related to UV exposure. A 2014 study found that suffering more than five accumulated sunburns during childhood and adolescence increases one's risk of melanoma by 80 percent and NMSC by 68 percent. Other risks for developing skin cancer including HPV infection, chronic inflammation, and immunosuppression.
Skin cancer in people of color is more often overlooked, leading to later diagnosis and lower survival rates for more severe cases. Skin cancer in darker-skinned people is more likely to affect non-sun-exposed areas, such as the nail bed and feet.
Prevention Is Key
Seeing as the majority of skin cancer is the result of the UV radiation all around us, cutting down exposure is key. Broad-spectrum sunscreens with SPF 30 or higher have been proven to significantly reduce UV light's negative effects on the skin. Other preventative measures include:
- Using sun-protective accessories and clothing when outdoors
- Seeking shade when the sun is strong (specifically, avoiding direct sun exposure from 10:00 a.m. to 2:00 p.m., when UV rays are strongest)
- Avoiding indoor tanning
- Seeing a Dermatologist regularly, as self-exams are not a substitute for professional skin exams—especially for those with a history of skin cancer or sunburns
Although the prospect of dealing with any type of skin cancer can be frightening, prevention, careful observation, and visits to your Dermatologist will go a long way in preserving your skin's health.