Baton Rouge Clinic Health Library

Cancer > Harmful Effects of Sun Exposure

     Published: 06, 2009

With the summer approaching, awareness about skin cancer and the harmful effects of sun exposure is of vital importance. The most common form of cancer in the United States is cancer of the skin. One million skin cancers are diagnosed every year in this country. The average American has a 20% chance of developing skin cancer in his or her lifetime.

The most common type of skin cancer is called basal cell carcinoma. Basal cell carcinoma is usually a pink or flesh-colored papule with visible blood vessels. This type of skin cancer has the best prognosis, as it is extremely rare to be associated with spread of the cancer to other areas of the body (metastasis). However, it can be destructive, with its potential to invade into the deeper layers of the skin and damage tissue. Basal cell carcinoma is thought to be caused by harmful ultraviolet rays from the skin, as it is most commonly found on sun exposed areas such as the face. Basal cell carcinoma can also develop on non-sun exposed areas. It is treated with a variety of methods, including surgical removal, electrosurgical destruction, and topical therapy.

The second most common type of skin cancer is called squamous cell carcinoma. Squamous cell carcinoma is usually a tender, crusted nodule with a tendency to bleed and scab. If squamous cell carcinoma is diagnosed and treated early, the prognosis is generally quite good. Failure to treat early can result in spread of cancer cells to lymph nodes and other areas and death (2,500 American deaths annually). Squamous cell carcinoma is very likely caused by sun exposure, especially chronic cumulative exposure. It is also treated with surgical removal, electrosurgery, and topical therapies.

Melanoma is the third and most deadly of all skin cancers. 8,000 Americans die of melanoma every year. The number of new cases per year is rising. It is usually a black, irregularly pigmented, asymmetric skin lesion with variable shades of color that arises within a previously-existing mole or within normal skin. Any changing mole should be examined by a dermatologist. Melanoma, if discovered and treated early, can be associated with a decent prognosis. If however it is not treated early, metastasis and death can occur. Sunburn is a major risk factor for this type of skin cancer. It is treated with surgical excision and, in some cases, lymph node dissection

Exposure to ultraviolet radiation from the sun may be responsible for 90% of nonmelanoma skin cancers and 65% of melanomas. It used to be said that the majority of sun exposure occurs in the first 18 years of a person’s life. This has been proven to be untrue – there is a more even distribution of sun exposure over the course of a lifetime. Indoor tanning also increases a person’s risk of developing skin cancer. A single exposure to a tanning bed during youth increases melanoma risk by 75 percent, squamous cell carcinoma by 2.5 times and basal cell carcinoma by 1.5 times. Not only does ultraviolet light exposure increase one’s risk of skin cancer, but it is also responsible for 90% of the changes that lead to aging of the skin.

With the summer approaching, protect yourself from the harmful effects of sunlight by taking the following measures:

• Apply a broad-spectrum, water-resistant sunscreen or sunblock with an SPF of 15 or higher to the sun-exposed areas, on both sunny and cloudy days. Reapply frequently.
• Wear a wide-brimmed hat, sunglasses, long-sleeved shirt, and pants.
• Look for shade.
• Understand that there is no safe way to tan. Tanning occurs as a response to ultraviolet damage of the skin.
• Talk to your doctor about healthy ways of getting Vitamin D – not from the sun.

Scott M. Jackson, MD, FAAD
Specializing in Dermatology

The Baton Rouge Clinic, AMC, offers this information as a courtesy service. Please remember that medical knowledge is always evolving and we cannot represent that any of our information is absolutely current. Please consult a physician before taking any medical action based on information gathered from this or any website.