Skin Cancer Overview

While other types of cancers tend to receive more attention in the news, social media, or other outlets such as television commercials, the most common cancer type in the United States is skin cancer. Typically, a majority of skin cancer cases are caused by overexposure to ultraviolet (UV) light rays from the sun, tanning beds, or sunlamps. UV light in the short term is the cause of sunburn, while long-term exposure leads to damage build up, changes in skin texture, and potentially skin cancer. Currently, estimates state that roughly 1 in 5 Americans will develop skin cancer during their lifetime, and approximately 9,500 US citizens are diagnosed daily.

The average American has a 20% risk of developing skin cancer in their lifetime

Factors that Increase Skin Cancer Risk

Diving into the Skin

The skin has multiple layers, but the two main layers are the epidermis (upper and outer layer) and the dermis (lower and inner layer). 

The epidermis is composed of three different kinds of cells:

• Squamous cells: Thin, flat cells that form the top layer. Cancer that forms here is termed squamous cell carcinoma of the skin. 
• Basal cells: Round cells underneath the squamous cells. Cancer here is called basal cell carcinoma. 
• Melanocytes: Found within the lower part of the epidermis, where melanin is produced, which is the pigment that provides skin its natural color. When sun exposure is intensified, melanocytes make more pigment and cause skin tanning or darkening. Cancer in this location is called melanoma. 

The dermis consists of blood, lymph vessels, hair follicles, and glands. 

Nonmelanoma skin cancer (squamous cell carcinoma and basal cell carcinoma) sees new cases at an increasing rate year annually, and nonmelanoma skin cancer can typically be cured. Oppositely, melanoma type cancer is more likely to spread throughout the body into nearby tissues, which makes it more difficult to cure.

Image: Centers for Disease Control and Prevention (CDC). Available at: https://www.cdc.gov/skin-cancer/about/index.html

Early Skin Cancer Screening and Learning your ABCDE’s

It’s critically important to get yourself screened early for all types of cancer, of course. This is because if and when cancer is detected at an earlier stage, it is easier to treat. The earlier the detection occurs, the more likely chance that the cancer has not spread to other parts of the body. Additionally, it is crucial to remember that if a provider recommends a screening, it does not mean he/she thinks you have cancer, more so that this can be a precautionary measure. Most insurance plans will cover this service for patients at low or no cost. 

There are five key areas that are under investigation during an early screening, and the “ABCDE” acronym depicted above tries to keep this easier to remember. 

• A: Asymmetry: is one half of the area different from the other half?
• B: Border: are there any jagged edges or other irregularities on the outer ring of the mark?
• C: Color: is the mark a uniform, single color?
• D: Diameter: is the mark greater than 6 millimeters in size?
• E: Evolution: does the skin mark change at all over time (size, shape, color)?

If any of these domains are found to be concerning, a biopsy may be performed by the provider for further investigation into the skin.

Image: CDC. Available at: https://www.cdc.gov/skin-cancer/symptoms/index.html

Medication’s Role in Skin Cancer Treatment

The first line therapy for skin cancer cells is topical fluorouracil (5-FU, sold under brand names Efudex, Carac, or Tolak). It’s typically dosed every twelve hours for 3-6 weeks, up to a limit of 10-12 weeks. As a topical, patients are supposed to use enough to cover their lesions, so total application volume varies for all, but the dosing schedule stays the same. 5-FU is supported by randomized clinical trials in literature investigating patients with sun damaged skin and actinic keratosis. “The fluorouracil group had fewer actinic keratosis cases when compared with the control group at 6 months (3.0 vs. 8.1: P < 0.001) and for the overall study duration (P < 0.001). Topical 5-FU also reduced the risk of squamous cell carcinoma (SCC) requiring surgery at those sites for 1 year, but no effect was seen on basal cell carcinoma (BCC) in 1 year or on SCC or BCC over 4 years.” 

Some other interventions have been cited for use as treatment against skin cancer, with less evidence for their support. Some of the options are as follows.

Overall, it is important for physicians and pharmacists alike to be aware of the different levels of evidence supporting the use of different medications, or alternate therapies such as behavioral interventions. Additionally, it is crucial for patients to follow these safe skin practice recommendations, and if medications are prescribed to aid in these practices, it is important to adhere to the regimen to maximize potential benefits.

Collin B., APPE Student

References: 

1. CDC. Skin Cancer Basics. Skin Cancer. Published February 22, 2024. https://www.cdc.gov/skin-cancer/about/index.html
2. USCS Data Visualizations. Cdc.gov. Published 2025. https://gis.cdc.gov/Cancer/USCS/#/special-topic/demographics?datatype=1&cancer=58&indicator=value&timeperiod=1&sexes=1_2_3&races=1&ages=23&tab=2&view=chart&xaxis=sexes
3. National Cancer Institute. Skin Cancer Prevention (PDQ®)–Patient Version. National Cancer Institute. Published April 10, 2019. https://www.cancer.gov/types/skin/patient/skin-prevention-pdq
4. Skin Cancer Prevention. National Cancer Institute. Published 2012. https://www.cancer.gov/types/skin/hp/skin-prevention-pdq
5. Weinstock MA, Thwin SS, Siegel JA, et al; Veterans Affairs Keratinocyte Carcinoma Chemoprevention Trial (VAKCC) Group. Chemoprevention of Basal and Squamous Cell Carcinoma With a Single Course of Fluorouracil, 5%, Cream: A Randomized Clinical Trial. JAMA Dermatol. 2018 Feb 1;154(2):167-174. 
6. Rosenberg AR, Tabacchi M, Ngo KH, Wallendorf M, Rosman IS, Cornelius LA, Demehri S. Skin cancer precursor immunotherapy for squamous cell carcinoma prevention. JCI Insight. 2019 Mar 21;4(6).
7. American Academy of Dermatology Association. Skin Cancer. American Academy of Dermatology Association. Published April 22, 2022. https://www.aad.org/media/stats-skin-cancer