Don’t wait for a diagnosis: how to protect yourself from skin cancer

Figure 1. Basal cell carcinoma visual characteristics: pink, pearly papule with telangiectasia (dilated blood vessels), and rolled borders. Image taken from https://exchange.scholarrx.com/brick/malignant-skin-tumors

As you may have heard, the skin is the largest organ of the human body. As the largest organ of the body, it has many functions: it serves as a barrier that protects against the external environment, supports thermoregulation, and participates in vitamin D and melanin synthesis. Since the skin’s major function is to protect the body from the surrounding environment, severe problems and diseases may arise if its barrier function is compromised. Cancer is one of those diseases that may arise from environmental exposure, especially UV radiation.

There are 3 types of skin cancers: basal cell carcinoma, squamous cell carcinoma, and melanoma. These 3 types of skin cancer have a common risk factor for developing: solar UV radiation exposure.

Although the types of skin cancer will be addressed briefly, please make sure to review the section on prevention, as it is the key focus of this blog.

Basal cell carcinoma

Basal cell carcinoma (BCC) is the most common skin cancer worldwide, comprising about 75-80% of all new skin cancers diagnosed. The primary risk factor for developing BCC is UV exposure. Also, individuals with lighter skin tone, eye color, and/or hair color are at increased risk. Other additional risk factors include chronic arsenic exposure, radiation therapy, and inherited disorders, such as basal cell nevus syndrome, xeroderma pigmentosum, and albinism. It can be developed from nonhealing wounds. Even though it rarely metastasizes, it may cause significant morbidity if left untreated.

How to identify?

Basal cell carcinoma is typically found in sun-exposed areas, mainly the face, neck, and upper lip. BCC is frequently slow-growing and commonly appears as a pink, pearly papule or plaque with dilated vessels and rolled borders and is often painless (figure 1). A characteristic feature of BCC is dilated blood vessels, called telangiectasia. The diagnosis of BCC is made by a dermatologist through a skin biopsy. For this reason, since dermatologists are specialists trained to perform skin biopsies and evaluate skin lesions, it is essential to consult one for suspicious skin lesions.

1. Squamous cell carcinoma

Squamous cell carcinoma (SCC) is the second most common skin cancer. The primary risk factor for SCC is cumulative sun exposure (either from sun or tanning beds). Chronic immunosuppression, chronic non-healing wounds, arsenic exposure, ionizing radiation, and light skin tone individuals are other risk factors. Typically appears on face, lower lips, ears, and hands. SCC tends to grow faster than BCC.

How to identify?

Different from basal cell carcinoma, squamous cell carcinoma has a premalignant lesion, called actinic keratosis. This premalignant lesion is caused by sun exposure and is described as small, rough, erythematous or brownish papule or plaque or as a cutaneous horn (figure 2).

Figure 2. Actinic keratosis, a premalignant lesion of squamous cell carcinoma. This image presents a left temporal and cheeks region of a 75-year-old female patient with long-term exposure to UV radiation. Yellow-brown, squamous changes can be seen in the lower two lesions, which indicates actinic keratosis. Image taken from https://next.amboss.com/us/article/Ik0Y6T?q=skin+cancer&m=gZYFan&full_screen=true

Squamous cell carcinoma tends to bleed easily after minor trauma and have a characteristic central ulceration (figure 3).

Figure 3. Squamous cell carcinoma of the nose with central ulceration. Image taken from https://next.amboss.com/us/article/Ik0Y6T?q=skin+cancer

2. Melanoma

Melanomas are a malignancy arising from melanocytes and are the most common cause of skin cancer-related death. As with the other 2 skin cancers, UV radiation is the most significant risk factor for developing melanoma. Some genetic mutations have been associated with this type of skin cancer. It is associated with dysplastic nevus/ atypical mole (benign but unusual-looking mole that has features of irregular borders, multiple colors, and a diameter >5mm). Melanomas have significant risk for metastasis.

How to identify?

Patients typically present with skin lesions that change in size, color, contour, or configuration (figure 4).

Figure 4. Melanoma with irregular borders, different colors. (https://exchange.scholarrx.com/brick/malignant-skin-tumors)

Dermatologists have a characteristic way to evaluate melanomas, which makes it easier for a person to evaluate suspicious skin lesions at home using the ABCDE mnemonic:

Prevention

Finally, the most important part of skin cancer, the prevention. Although skin cancer is commonly a visible lesion, it is important to consult a dermatologist for further evaluation. Here are some recommendations to prevent skin cancer:

Avoid intense or high solar UV exposure by seeking shade.
Avoid UV radiation for tanning, including sunbeds.
Avoid use of indoor tanning devices.
Use physical protection with clothing, such as wide-brimmed hat and sunglasses.
Use a broad-spectrum UVA+UVB sunscreen with sun protection factor +30-50+ SPF. It is recommended to apply every day in the face, ears, neck, scalp if uncovered and all parts of the body that are not covered by clothing.
Babies under the age of 6 months should not be exposed to direct sunlight.

Avoidance of high/intense UV exposure constitutes the first pillar in UV protection and skin cancer prevention. The UV index quantifies the intensity of solar UV radiation reaching the Earth's surface, on a scale from 1 to 11 +. According to the World Health Organization, sun protection measures are advised starting from UV index 3 (moderate) (figure 5). UV intensity is highest between 10:00am-2:00pm, and therefore it is recommended to seek shade during these hours of the day or to stay indoors. It has been shown in epidemiological studies that the development of nevi in children and melanoma through sun protection by clothes, as compared to sunscreens, have a reduced risk for developing skin cancer. Clothing with a high UV Protection Factor is particularly useful in high UV exposure conditions such as outdoor sports and water sports. Also, hats should have a wide brim to protect the head, face, neck, and ears.

Figure 5. UV index scale (https://preventcancer.org/es/article/uv-index/)

Evidence from observational studies, a large randomized controlled trial, and smaller, nonrandomized experimental studies supports the effectiveness of sunscreens in preventing the signs of photoaging, wrinkles, telangiectasia, and pigmentary alterations induced by ultraviolet radiation. It has been found that spray-on sunscreens are less desirable than cream-based ones for many reasons: wind can disperse the sunscreen, resulting in poor or inadequate application, due to fast drying and not clearly visible once sprayed onto the skin, it is difficult to determine whether the application was homogeneous, and also because spray-on sunscreens are also flammable, several incidences of combustion on the skin have been reported after exposure to open flames. In figure 6 I leave you a visual guide of the recommended amounts of sunscreen for its correct application to the body.

Figure 6. Visual guide for sunscreen application on the whole body. Image taken from https://www.cmaj.ca/content/192/50/E1802/tab-figures-data

These recommendations apply to all fair-skinned individuals, outdoor workers, children, and people at high risk of skin cancer.

Finally, we cannot leave this blog without talking about the different types of UV radiation. There are 3 main types of UV rays that the sun is emitting right now: UVA, UVB, and UVC. Almost all the UV radiation reaching the earth is UVA rays, accounting 95% to be precise, which is the main cause of photoaging due to their ability to penetrate deeper into the skin. UVA rays induce DNA damage mediated by the formation of free radicals via reactive oxygen species and decrease the activity of antigen-presenting cells of the epidermis. On the contrary, UVB rays are known as sunburn rays and are more classically associated with skin cancer than UVA tanning rays. UVB radiation induces DNA lesions forming pyrimidine cross-links, such as pyrimidine dimers, between neighboring DNA base pairs. Finally, the third type of rays, the UVC rays, although more damaging to the skin than UVA and UVB, are completely absorbed by the ozone layer, and therefore, they do not increase the risk of skin cancer.

References

AMBOSS GmbH. Skin and skin appendages. https://amboss.com/ . Accessed December 3, 2025.
AMBOSS GmbH. Skin cancer. https://amboss.com/. Accessed December 3, 2025.
Brick Exchange. (n.d.). https://exchange.scholarrx.com/brick/malignant-skin-tumors
Garbe, C., Forsea, A.-M., Amaral, T., Arenberger, P., Autier, P., Berwick, M., Boonen, B., Bylaite, M., Del Marmol, V., Dreno, B., Fargnoli, M. C., Geller, A. C., Green, A. C., Greinert, R., Hauschild, A., Harwood, C. A., Hoorens, I., Kandolf, L., Kaufmann, R., … Brochez, L. (2024). Skin cancers are the most frequent cancers in fair-skinned populations, but we can prevent them. European Journal of Cancer (Oxford, England: 1990), 204(114074), 114074. https://doi.org/10.1016/j.ejca.2024.114074
Guerra, K. C., Zafar, N., & Crane, J. S. (2023, 8 agosto). Skin cancer prevention. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK519527/
Prevent Cancer Foundation. (2025, June 26). What is UV index? - Prevent Cancer Foundation. https://preventcancer.org/es/article/uv-index/
Sander, M., Sander, M., Burbidge, T., & Beecker, J. (2020). The efficacy and safety of sunscreen use for the prevention of skin cancer. Canadian Medical Association Journal, 192(50), E1802–E1808. https://doi.org/10.1503/cmaj.201085