JAMA Study Casts Shadow Over Young Sunbathers

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At a time when Americans are basking in the summer sun, a study published in this week s Journal of the American Medical Association (JAMA) reports some sobering news: the incidence of nonmelanoma skin cancer seems to be on the rise in people under the age of forty.

Nonmelanoma skin cancer (which includes basal and squamous cell carcinomas) is the most common form of cancer in the United States, with more than one million cases diagnosed each year. They are far more common than melanoma but less invasive and more easily curable, especially with early detection.

Relying on medical records to track trends from 1976 through 2003, the JAMA study examined the rates of nonmelanoma skin cancers in a Minnesota population and found a statistically significant increase in incidence over time. The authors state that their data can be generalized to the Caucasian population in the United States.

The study points out that increased longevity (and therefore greater cumulative sun exposure) is often implicated as a major cause for the increase in rates of these skin cancers -- at least in older populations. However, the fact that skin cancer incidence is also increasing in people under age forty points to other factors, both discouraging and encouraging, that may be unique to the younger population.

On one hand, the rising rates may indicate an increase in the actual occurrence of these cancers. For nonmelanoma skin cancers, exposure to UV radiation -- whether from natural sun exposure or the use of tanning beds -- is the most important and common risk factor. Interestingly, young people with skin cancer are more likely than older victims to get lesions on the torso as opposed to the head or neck (generally, 80% to 90% of nonmelanoma skin cancers are found on the head or neck, in contrast to approximately 60% in the JAMA study population). According to research cited by JAMA, this difference suggests that intense, shorter-term sun exposure may be more to blame for these cancers.

On the other hand, greater awareness of and monitoring for skin cancer may explain the observed increase in rates. The authors claim, however, that because the stage and size at which the cancers were detected did not decrease over the time period they studied, this factor is not likely to be the primary reason for the increase in diagnosis. In contrast, a study in last week's British Medical Journal indicated that because an increase in melanoma diagnoses in the older population has occurred only for early stage melanoma, increased diagnosis rather than increased occurrence accounts for the recent rise.

Either way, the JAMA study underscores the importance of both preventing and raising awareness about skin cancer in young adults, who are particularly likely to be unaware of the risks. Limiting UV exposure (as by regularly using sunscreen and restricting direct midday sun exposure) is important in preventing skin cancer. Learning what skin cancers look like and monitoring for them can be crucial for early detection of this common, but most often easily treatable, cancer.

For more information about skin cancer, see www.skincancer.org

Reference: Christenson, LJ, Borrowman, TA, Vachon, CM, et al. Incidence of Basal Cell Carcinoma and Squamous Cell Carcinoma in a Population Younger Than 40 Years. JAMA. 2005; 294:681-690.

Rivka Weiser is an assistant director of public health at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).