The findings, which were based on self-reporting of sunburn and sun protection practices gathered from the National Health Interview Survey, urge skin doctors and other health care providers to better educate their patients about protective skin care practices, especially for those with history of nonmelanoma skin cancer. The findings are published in the Journal of the American Academy of Dermatology.
"It is important to look at how patients are currently practicing sun protection and what they are doing that is not very effective," says Anna Chien, M.D., co-director of the Cutaneous Translational Research Program in the Department of Dermatology at the Johns Hopkins University School of Medicine. "Only then can we make strides in helping patients improve their sun protective practices by ensuring they do them the correct way." Sun exposure is the leading cause of nonmelanoma skin cancers, and treatment is estimated to cost $4.8 billion in the U.S. annually.
In the United States, Chien says, approximately 13 million white non-Hispanic individuals have a history of at least one type of nonmelanoma skin cancer, including basal cell and squamous cell cancers, putting them at a well-documented higher risk for subsequent nonmelanoma skin cancer. For example, studies show that 40 percent of those with a history of basal cell carcinoma are diagnosed with another lesion within five years.
For the new study, investigators analyzed self-reported survey results about sun protective practices from 758 people with previous nonmelanoma skin cancer and from 34,161 people without a history of skin cancer. The study focused on non-Hispanic whites, the population most affected by nonmelanoma skin cancer. Of the people without history, 18,933 were female and 15,228 were male, and of those with history, 390 were female and 368 were male.
The researchers defined protective practices as using sunscreen when going outside on a sunny day for more than an hour, wearing long sleeves or a wide-brimmed hat, and staying in the shade when outside on a sunny day for more than one hour. They defined sun avoidance as not going out into the sun.
Overall, they concluded that 44.3 percent of people with nonmelanoma skin cancer history reported frequent use of shade, compared to 27 percent of people without a history of skin cancer, and 20.5 percent of those with a history of nonmelanoma skin cancer wore long sleeves, compared to 7.7 percent of those with no history.
Additionally, 26.1 percent of those with a history of nonmelanoma skin cancer said they wore a wide-brimmed hat when outside in the sun, compared to 10.5 percent of people without a history, and 53.7 percent of those with a history of nonmelanoma skin cancer said they wore sunscreen, compared to 33.1 percent of those without a history.
Moreover, 44.7 percent of those with a history of nonmelanoma skin cancer reported using more than one form of sun protection, while only 19.4 percent of those without a history of nonmelanoma skin cancer said they did so. Multimodality, the use of multiple skin-protective practices at a time, was associated with lower odds of sunburn. It also offers a highly beneficial approach to those with previous nonmelanoma skin cancer, says Chien.
Most importantly, the researchers say, was the finding that although people with previous nonmelanoma skin cancer tend to use one or all of the protective practices, there was not a significant difference in reporting of sunburn compared to those without a history -- 29.7 percent versus 40.7 percent. This means, Chien says, that although those with a history of skin cancer are proactively using protective methods, they may not be doing so effectively, especially among younger patients. Approximately two-thirds (66.9 percent) of individuals ages 18 to 39 reported sunburn.
Chien says that while sunscreen was the most common use of sun protection reported by participants, it was not associated with lower rates of sunburn in those with previous nonmelanoma skin cancer. While noting that self-reports, such as those on which the study is based, are not entirely reliable, the disconnect among those who use sunscreen and still get burned may occur because individuals are not applying sunscreen effectively. Explaining the correct ways -- such as how much and how often -- to apply sunscreen to patients is key, says Chien.
"These results suggest that physicians need to go the extra step in educating patients on the most optimal way of utilizing sun protection methods. Public health messages should also emphasize not only sun protection but how to do it correctly," Chien says.
The researchers caution that although the data were pulled from a national survey, the results are self-reported and therefore may have some bias. In addition, Chien says, nonmelanoma skin cancer tends to be considered less important than melanoma and is thus under-reported.
"The bottom line is that people should be using multiple forms of skin protective practices," says Chien. "That means incorporating shade or sun avoidance into a daily routine, or wearing a wide-brimmed hat while also applying sunscreen correctly."
Fischer et al. Sunburn and sun-protective behaviors among adults with and without previous nonmelanoma skin cancer (NMSC): A population-based study. J. Am. Acad. Dermatol. 2016;75:371–379 [Abstract]