Sunscreen Use and Melanoma

What is the problem and what is known about it so far?

Melanoma is a cancer of cells in the skin that produce a brown pigment called melanin. Risk factors for melanoma include a family history of melanoma, large numbers of moles and freckles, sun sensitivity (light skin color, tendency to burn, and inability to tan), and exposure to ultraviolet (UV) radiation from the sun or sunlamps and tanning beds. The number of people who get melanomas is increasing faster than any other type of cancer in the United States. Some people think that this number is increasing mainly because people are spending more time in the sun.

Most doctors believe that sunscreens help prevent skin cancer, including melanoma. However, a few reports suggest that sunscreen use may increase rather than decrease risk for melanoma. These reports are difficult to interpret. They don't always account for the possibility that light-skinned people with a higher risk for melanoma might use sunscreens more than do darker-skinned people with a lower risk.

Why did the researchers do this particular study?

To summarize data about the relationship between sunscreen use and risk for melanoma.

Who was studied?

People with and without melanoma from 18 different studies.

How was the study done?

Rather than doing a new study, the investigators searched the medical literature from 1966 to May 2003 to identify relevant past research. They found 18 case–control studies that examined whether patients with melanoma (cases) reported using sunscreen more or less often than did people without melanoma (controls). The researchers assessed the quality of the studies and summarized their results.

What did the researchers find?

The investigators found no good evidence that people who use sunscreens have an increased risk for melanoma. Several studies did not adequately account for the possibility that people with high risks might use sunscreen more than do people with low risks. A few studies that did account for people's risk factors suggested that sunscreen use is associated with decreased risk for melanoma.

What were the limitations of the study?

Many of the studies that were reviewed were old. The older studies did not have data about newer sunscreens with a sun protection factor (SPF) greater than 15, the ability to block both UVB and UVA radiation (which have different wavelengths), or water resistance. Also, studies were retrospective case–control studies that relied on people's memories of sun exposure and sunscreen use.

What are the implications of the study?

Current evidence suggests that sunscreen use is not associated with increased risk for melanoma.