Skin Cancer Risk Factors and Prevention

Skin cancer refers to abnormal, unmitigated growth of the various epidermal cells. It is the most prevalent type of cancer in the United States; it’s estimated that over 5 million Americans are living with skin cancer and more cases are diagnosed each year than all other cancers combined. Despite efforts to encourage prevention, incidences of skin cancer are rapidly increasing each year.

In this article, we’ll review some basic information regarding skin cancer, the typical prognosis after a case is diagnosed depending on the type, and finish with a look at risk factors, and prevention methods.

Skin Cancer Basics

There are 3 common skin cancer types named for the cells in which cancer originates:

1. Basal cell carcinoma (BCC), a form of non-melanoma skin cancer that affects the inner layer of the epidermis. BCC often appears as transparent bumps, thick brown lesions, or sores on the skin.
2. Squamous cell carcinoma (SCC), a form of non-melanoma skin cancer that affects the outer layer of the epidermis. SCC presents a range of sores and blemishes - red bumps, warts, dry patches, etc. Affected areas may bleed or crack.
3. Melanoma, a form of skin cancer that affects melanocytes, the cells that cause brown pigmentation in the skin and eyes. Melanoma usually shows up as brown or black spots on the skin. Benign (non-cancerous) melanoma often present as birthmarks and moles and may rarely (about 20%  of the time) develop into malignant growths.

In addition to the more common types, there are several more rare forms of non-melanoma skin cancer such as Merkel cell carcinoma (MCC). MCC affects neuroendocrine cells that grow near the ends of nerves and is one of the most deadly, pervasive forms of skin cancer.

Prognosis

The prognosis for all types is good provided the cancer is detected early. However, skin cancer mortality rates vary significantly among type and stage.

Most non-melanoma skin cancers - including basal and squamous cell - are easy to treat compared to melanoma IF they don’t become invasive or metastatic. In most cases, a simple excision to remove the affected tissue is all that’s required. If cancer spreads, treatment becomes more complicated, and the risk associated with treatment increases.

Basal cell carcinomas are the most common type of skin cancer, representing about 80% of all skin cancer diagnoses but BCC is also the least deadly; the 5-year relative survival rate for BCC is 100%.  Squamous cell carcinomas are less common (less than 20% of new cases) but also more deadly, with a 5-year relative survival rate of about 98%.

Melanoma, the least common type of skin cancer (about 1% of all cases), is also the most deadly with a 92% 5-year survival rate for all forms. If melanoma is allowed to grow, it may infiltrate the lymphatic tissue, and 64% of cases will survive. The 5-year survival rate among cases of metastasized melanoma (melanoma that has infiltrated distant tissues) is only about 23%.

Risk Factors

Skin cancer forms when the cells of the epidermal tissues become damaged. The DNA of damaged cells mutates resulting in rapid, uncontrolled cell growth. The most common sites of skin cancer are parts of the body that receive regular sun exposure - the face, ears, lips, scalp, shoulders, neck, back, and hands. 90% of cases of non-melanoma skin cancer and 86% of cases of melanoma skin cancer are associated with cumulative exposure to ultraviolet radiation from the sun, making sun exposure the leading preventable cause of skin cancer.

Indoor tanning is another major preventative risk factor due to UV radiation. It’s estimated that indoor tanning devices can be linked to more than 400,000 skin cancer incidences each year. A person with any history of indoor tanning has a 29% increased risk of developing basal cell carcinoma and a 67% increased risk of developing squamous cell carcinoma in their lifetime. If you first use an indoor tanning device before age 35, you develop a 75% greater risk of melanoma.

Because melanin, the brown pigment produced by the skin's melanocytes protects skin against UV radiation, people with fair skin and light hair are at an increased risk of developing skin cancer. It's important to remember however that everyone(even people with darker skin) can get skin cancer from UV damage.

Some medications may cause increased photosensitivity including some of the most commonly prescribed and over-the-counter drugs on the market. Antibiotics, antihistamines, antifungals, non-steroidal anti-inflammatories, and even oral contraceptives can increase susceptibility to UV radiation.

Prevention

Since cumulative exposure to ultraviolet radiation is the leading cause of skin cancer, protecting yourself from the harmful effects of the sun is absolutely crucial. Limit your time outside during the times when the UV index is highest - especially if you live in a tropical or subtropical region - and apply SPF 30 or higher sunscreen daily.

If you must spend a significant amount of time in the sun, wear clothing designed to absorb UV and shield your neck and head from the sun by donning a hat when you go outside during the day. Sunglasses with UV-absorbing lenses can help keep your eyes safe. Limit or completely abstain from the use of indoor tanning equipment.

Early detection of skin cancer is crucial in reducing the risk of mortality. It’s recommended that everyone (even people who spend most of their time inside) perform a monthly head-to-toe self-examination of their skin. Take note of and keep track of any new lesions and monitor changes to existing ones. The Skin Cancer Foundation has a helpful step-by-step self-exam guide available here.