Skin cancer is the most common type of cancer, and melanoma is the most serious of skin cancers. Like most cancers, the exact cause is not known. But, exposure to ultraviolet radiation is a strong risk factor.
We are most exposed to ultraviolet radiation through the sun. UV radiation, though, also comes from artificial sources, like sun lamps or tanning booths. Avoiding the artificial sources is easy, but decreasing exposure to the sun's radiation takes a bit more work. Many medical organizations, including the American Cancer Society, recommend wearing protective clothing, a hat, and sunscreen when you will be in strong sunlight. While we know sunscreen is effective at blocking UV radiation and decreasing the risk of sunburns, there have been no studies that show if sunscreen can actually decrease risk of melanoma.
Researchers from Australia examined the association between sunscreen use and risk of melanoma. The study, published in the Journal of Clinical Oncology, found that sunscreen use was, in fact, associated with a decrease in the risk of melanoma.
About the Study
The randomized trial included 1,621 adults in Australia, aged 25-75 years. The participants were divided into one of four different treatment groups over 4.5 years:
- Daily SPF 16 sunscreen application to head, neck, arms, and hands plus beta-carotene 30 mg daily
- Sunscreen choice and application done at participants discretion plus beta-carotene
- Daily sunscreen application plus placebo
- Sunscreen choice and application done at participants discretion plus placebo
The participants were then sent follow-up surveys 10 years after the trial was completed. During this extension period, no sunscreen was provided for any participants. However, some of the patients continued to use daily sunscreen. By the end of the full trial (14.5 years), researchers found:
- Primary melanoma developed in 1.3% of participants originally assigned to daily sunscreen compared to 2.7% of participants originally assigned to discretionary sunscreen.
This means that for every 72 participants told to use sunscreen daily, 1 participant avoided getting melanoma.
How Does This Affect You?
Randomized trials are generally considered a very reliable form for studies. This study was a 10-year follow-up of a randomized trial. Since it was not part of the original trial, there may be some reliability problems with the outcomes of this trial. However, since it is clear that sunscreen can block UV radiation and decrease painful sunburns, it is likely that daily sunscreen use may also decrease the development of melanoma. There is also very little risk with sunscreen use for most people.
Talk to your doctor about your risk factors for melanoma. Take steps to be healthy in the sun. Avoid sunburns by wearing protective clothing or sunscreen with SPF 15 or higher if you plan to be in the sun for extended periods of time, especially between 10 am and 4 pm. Do not increase your UV radiation exposure through artificial sources, like tanning beds. Finally, learn about the signs of melanoma and contact your doctor if you find any suspicious moles.
- Reviewer: Brian P. Randall, MD
- Review Date: 03/2011 -